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Springer Proceedings in Energy
Abdallah Khellaf Editor
Advances in
Renewable
Hydrogen and
Other Sustainable
Energy Carriers

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Abdallah Khellaf
Editor
AdvancesinRenewable
HydrogenandOther
SustainableEnergyCarriers
123

Editor
Abdallah Khellaf
Centre de Développement des Energies
Renouvelables
Algiers, Algeria
ISSN 2352-2534 ISSN 2352-2542 (electronic)
Springer Proceedings in Energy
ISBN 978-981-15-6594-6 ISBN 978-981-15-6595-3 (eBook)
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Preface
With the advent of the energy transition, hydrogenﬁeld use has widen. Indeed
initially hydrogen, as an energy vector and an alternative fuel, has been considered
in conjunction with renewable energy in order to address the issue of conventional
energy sources depletion and the problem of pollution resulting from the use
of these conventional energy sources. With the emergence of energy transition and
the massive introduction of renewables in the energy mix, the hydrogen role has
expanded. System energy stability and mismatch of energy supply and demand has
become acute. Recourse to hydrogen and its technologies and processes such
power-to-gas offer suitable solutions to address these issues. This situation has led
to an increase need for hydrogen, giving an impetus to its technology development
and offering divers applications to the other sectors.
It is in light of these developments that the third International Symposium on
Sustainable Hydrogen (ISSH2’2019) has been organized November 27–28, 2019,
in Algiers, Algeria.
The main topic of the symposium is hydrogen as an energy vector, an alternative
fuel, a storage medium and a buffer product. Hydrogen is considered as one of the
keys to the successful transition to sustainable and clean energy and one of the
undertakings where development is completely compatible with environment
protection.
This year’s special topic is“promising alternative fuels.”It has been selected to
draw attention to the new concepts and new resources and technologies considered
to overcome the practical challenges in achieving low-carbon energy society. With
their technologies improving at fast paces, these fuels are likely to play a central
role in socio-economic development, energy access and climate change mitigation.
The various thematic sessions have dealt with the scientiﬁc advances, the
experience gained, the provided opportunities, the encountered hurdles and the
actions to undertake to ensure sustainable development in theﬁelds of alternative
fuels and energy.
A panel discussion addressing the topic of“Hydrogen: Energy storage and
Energy transition”has been organized on theﬁrst day of the symposium with the
active participation of all the attendees. A debate has been carried out on advances
v

in hydrogen as a storage medium and as a buffer product and its role in the success
of the energy transition.
We are grateful to our sponsors (IAHE, TIKA, NAFTAL, Sonelgaz, BDL,
CASH, Lamaraz, Envilab) who have assisted us in organizing this event.
We also kindly thank the Algerian National Library (Bibliothèque Nationale
d’Algérie) for graciously providing their conference facilities for the organization
of the symposium.
Algiers, Algeria
The Steering Committee
Abdallah Khellaf
Rafika Boudries
Fethia Amrouche
Nourdine Kabouche
Abdelhamid Mraoui
Fatiha Lassouane
Ilyes Nouicer
Sabah Menia
Mounia Belacel
March 2020
Yasmina Bakouri
vi Preface

Contents
1 Hydrogen Storage: Different Technologies, Challenges
and Stakes. Focus on TiFe Hydrides
........................ 1
David Chapelle, Anne Maynadier, Ludovic Bebon,
and Frédéric Thiébaud
2 Preparation of ZrO
2–Fe2O3Nanoparticles and Their Application
as Photocatalyst for Water Depollution and Hydrogen
Production
........................................... 11
M. Benamira, N. Doufar, and H. Lahmar
3 Preparation of Anode Supported Solid Oxide Fuel Cells
(SOFCs) Based on BIT07 and Pr
2NiO4+d:Inﬂuence
of the Presence of GDC Layer
............................ 19
M. Benamira, M. T. Caldes, O. Joubert, and A. Le Gal La Salle
4 Preparation of the Spinel CuCo
2O4at Low Temperature.
Application to Hydrogen Photoelectrochemical Production
.......25
R. Bagtache, K. Boudjedien, I. Sebai, D. Meziani,
and Mohamed Trari
5 Synthesis and Electrochemical Characterization of Fe-Doped
NiAl
2O4Oxides........................................ 33
Warda Tibermacine and Mahmoud Omari
6 Review on the Effect of Compensation Ions on Zeolite’s
Hydrogen Adsorption
................................... 41
Redouane Melouki and Youcef Boucheffa
7 Catalytic Reforming of Methane Over Ni–La
2O
3and Ni–CeO
2
Catalysts Prepared by Sol-Gel Method...................... 47
Nora Yahi, Kahina Kouachi, Hanane Akram,
and Inmaculada Rodríguez-Ramos
vii

8 Hydrogen Effect on Soot Formation in Ethylene-Syngas
Mixture Opposed Jet Diffusion Flame in Non-conventional
Combustion Regime
.................................... 55
Amar Hadef, Selsabil Boussetla, Abdelbaki Mameri,
and Z. Aouachria
9 A Two-Dimensional Simulation of Opposed Jet Turbulent
Diffusion Flame of the Mixture Biogas-Syngas
................ 61
Abdelbaki Mameri, Selsabil Boussetla, and Amar Hadef
10 Numerical Evaluation of NO Production Routes in the MILD
Combustion of the Biogas-Syngas Mixture
................... 69
Selsabil Boussetla, Abdelbaki Mameri, and Amar Hadef
11 Effect of H
2/CO Ratio and Air N2Substitution by CO2
on CH4/Syngas Flameless Combustion...................... 77
Amar Hadef, Abdelbaki Mameri, and Z. Aouachria
12 Chaotic Bacterial Foraging Optimization Algorithm
with Multi-cross Learning Mechanism for Energy Management
of a Standalone PV/Wind with Fuel Cell
.................... 85
Issam Abadlia, Mohamed Adjabi, and Hamza Bouzeria
13 Mechanical Properties of the Tetragonal CH
3NH3PbI3
Structure............................................. 93
Kamel Benyelloul, Smain Bekhechi, Abdelkader Djellouli,
Youcef Bouhadda, Khadidja Khodja, and Haﬁd Aourag
14 Hydrogen Production by theEnterobacter cloacaeStrain
........99
Azri Yamina Mounia, Tou Insaf, and Sadi Meriem
15 Visible Light Hydrogen Production on the Novel Ferrite
CuFe
2O4............................................. 105
S. Attia, N. Helaïli, Y. Bessekhouad, and Mohamed Trari
16 Prediction of New Hydrogen Storage Materials: Structural
Stability of SrAlH
3from First Principle Calculation............113
Youcef Bouhadda, Kamel Benyelloul, N. Fenineche,
and M. Bououdina
17 CFD Analysis of the Metal Foam Insertion Effects on SMR
Reaction Over Ni/Al
2O3Catalyst.......................... 121
Ali Cherif, Rachid Nebbali, and Lyes Nasseri
18 Photocatalytic Evolution of Hydrogen on CuFe
2O4.............129
H. Lahmar, M. Benamira, L. Messaadia, K. Telmani, A. Bouhala,
and Mohamed Trari
19 CFD Study of ATR Reaction Over Dual Pt–Ni Catalytic Bed
.....137
Ali Cherif, Rachid Nebbali, and Lyes Nasseri
viii Contents

20 Optimization of the Ni/Al2O3and Pt/Al2O3Catalysts Load
in Autothermal Steam Methane Reforming
................... 145
Ali Cherif, Rachid Nebbali, and Lyes Nasseri
21 Proton Exchange Membrane Fuel Cell Modules for Ship
Applications
.......................................... 151
S. Tamalouzt, N. Benyahia, and A. Bousbaine
22 Analysis of off Grid Fuel Cell Cogeneration for a Residential
Community
........................................... 161
A. Mraoui, B. Abada, and M. Kherrat
23 Tri-generation Using Fuel Cells for Residential Application
......171
A. Mraoui, B. Abada, and M. Kherrat
24 Response Surface Methodology Based Optimization
of Transesteriﬁcation of Waste Cooking Oil
.................. 177
R. Alloune, M. Y. Abdat, A. Saad, F. Danane, R. Bessah, S. Abada,
and M. A. Aziza
25 Numerical Investigation on Concentrating Solar Power Plant
Based on the Organic Rankine Cycle for Hydrogen Production
in Ghardaïa
........................................... 185
Halima Derbal-Mokrane, Fethia Amrouche, Mohamed Nazim Omari,
Ismael Yahmi, and Ahmed Benzaoui
26 Optimization Study of the Produced Electric Power
by PCFCs
............................................ 195
Youcef Sahli, Abdallah Mohammedi, Monsaf Tamerabet,
and Hocine Ben-Moussa
27 Accurate PEM Fuel Cell Parameters Identiﬁcation Using Whale
Optimization Algorithm
................................. 203
Mohammed Bilal Danoune, Ahmed Djafour,
and Abdelmoumen Gougui
28 Hydrogen Versus Alternative Fuels in an HCCI Engine:
A Thermodynamic Study
................................ 211
Mohamed Djermouni and Ahmed Ouadha
29 Thermodynamic Study of a Turbocharged Diesel-Hydrogen Dual
Fuel Marine Engine
.................................... 221
Fouad Selmane, Mohamed Djermouni, and Ahmed Ouadha
30 Effect of Bluff-Body Shape on Stability of Hydrogen-Air Flame
in Narrow Channel
..................................... 231
Mounir Alliche, Redha Rebhi, and Fatma Zohra Khelladi
Contents ix

31 Experimental Validation of Fuel Cell, Battery
and Supercapacitor Energy Conversion System for Electric
Vehicle Applications
.................................... 239
R. Moualek, N. Benyahia, A. Bousbaine, and N. Benamrouche
32 Compromise Between Power Density and Durability of a PEM
Fuel Cell Operating Under Flood Conditions
................. 247
H. Abdi, N. Ait Messaoudene, and M. W. Naceur
33 Optimal Design of Energy Storage System Using Different
Battery Technologies for FCEV Applications
................. 255
B. Bendjedia, N. Rizoug, and M. Boukhnifer
34 Simultaneous Removal of Organic Load and Hydrogen Gas
Production Using Electrodeposits Cathodes in MEC
............263
Amit Kumar Chaurasia and Prasenjit Mondal
35 An Improved Model for Fault Tolerant Control of a Flooding
and Drying Phenomena in the Proton Exchange Membrane
Fuel Cell
............................................. 271
A. A. Smadi, F. Khoucha, A. Benrabah, and M. Benbouzid
36 Design of a Microbial Fuel Cell Used as a Biosensor of Pollution
Emitted by Oxidized Organic Matter
....................... 279
Amina Benayyad, Mostefa Kameche, Hakima Kebaili,
and Christophe Innocent
37 Bioelectricity Production fromArundo Donax-MFC
andChlorophytum Comosum-MFC
......................... 285
L. Benhabylès, Y. M. Azri, I. Tou, and M. Sadi
38 Implementation of Fuel Cell and Photovoltaic Panels Based DC
Micro Grid Prototype for Electric Vehicles Charging Station
.....291
N. Benyahia, S. Tamalouzt, H. Denoun, A. Badji, A. Bousbaine,
R. Moualek, and N. Benamrouche
39 Application of Hydrotalcite for the Dry Reforming Reaction
of Methane and Reduction of Greenhouse Gases
.............. 299
Nadia Aider, Fouzia Touahra, Baya Djebarri, Ferroudja Bali,
Zoulikha Abdelsadek, and Djamila Halliche
40 Processing of CO
xMolecules in CO2/O2Gas Mixture
by Dielectric Barrier Discharge: Understanding the Effect
of Internal Parameters of the Discharge
..................... 307
L. Saidia, A. Belasri, and S. Baadj
41 Performance Comparison of a Wankel SI Engine Fuelled
with Gasoline and Ethanol Blended Hydrogen
................ 315
Fethia Amrouche, P. A. Erickson, J. W. Park, and S. Varnhagen
x Contents

42 Parametric Study of SO3Conversion to SO2in Tubular Reactor
for Hydrogen ProductionviaSulfuric Cycle
.................. 323
F. Lassouane
43 Preparation and Physical/Electrochemical Characterization
of the Hetero-System 10% NiO/c–Al
2O3..................... 331
I. Sebai, R. Bagtache, A. Boulahaouache, N. Salhi,
and Mohamed Trari
44 Synthesis and Characterization of the Double Perovskite
La
2NiO4-Application for Hydrogen Production................ 339
S. Boumaza, R. Brahimi, L. Boudjellal, Akila Belhadi,
and Mohamed Trari
45 Optimal Design and Comparison Between Renewable Energy
System, with Battery Storage and Hydrogen Storage:
Case of Djelfa, Algeria
.................................. 347
Ilhem Nadia Rabehi
46 New Neural Network Single Sensor Variable Step Size MPPT
for PEM Fuel Cell Power System
.......................... 355
Abdelghani Harrag
47 Modiﬁed P&O-Fuzzy Type-2 Variable Step Size MPPT for PEM
Fuel Cell Power System
................................. 363
Abdelghani Harrag
48 A GIS-MOPSO Integrated Method for Optimal Design
of Grid-Connected HRES for Educational Buildings
...........371
Charafeddine Mokhtara, Belkhir Negrou, Noureddine Settou,
Abdessalem Bouferrouk, Yufeng Yao, and Djilali Messaoudi
49 A Comparison Between Two Hydrogen Injection Modes
in a Metal Hydride Reactor
.............................. 379
Bachir Dadda, Allal Babbou, Rida Zarrit, Youcef Bouhadda,
and Saïd Abboudi
50 Effect of the Complexing Agent in the Pechini Method
on the Structural and Electrical Properties of an Ionic Conductor
of Formula La
1−xSrxAlO3−d(x = 0, 0.05, 0.1, 0.15).............387
F. Hadji, F. Bouremmad, S. Shawuti, and M. A. Gulgun
51 Production of Bio-Oil for Chemical Valorization by Flash
Pyrolysis of Lignocellulosic Biomass in an Entrained
Bed Reactor
.......................................... 395
Imane Ouarzki, Aissa Ould Dris, and Mourad Hazi
Contents xi

52 Suitable Sites for Wind Hydrogen Production Based
on GIS-MCDM Method in Algeria
......................... 405
Djilali Messaoudi, Noureddine Settou, Belkhir Negrou,
Belkhir Settou, Charafeddine Mokhtara,
and Chetouane Mohammed Amine
53 Liquefaction of Hydrogen: Comparison Between Conventional
and Magnetic Refrigeration Systems
........................ 413
Mustapha Belkadi and Arezki Smaili
54 Numerical Study of Heat and Mass Transfer During Absorption
of H
2in a LaNi5Annular Disc Reactor Crossed by a Tubular
Heat Exchanger
....................................... 421
Abdelaziz Bammoune, Samir Laouedj, and Bachir Dadda
55 Photocatalytic Hydrogen Production on 5% CuO/ZnO
Hetero-Junction
....................................... 429
Meriem Haddad, Akila Belhadi, and Mohamed Trari
56 Field Enhancement Factor Around Hydrogen-Negative Index
Metamaterial Waveguide
................................ 435
Houria Hamouche and Mohammed M. Shabat
57 Effect of Silicates and Carbonates on the Structure
of Nickel-Containing Hydrotalcite-Derived Materials
...........443
Baya Djebarri, Nadia Aider, Fouzia Touahra, Ferroudja Bali,
Juan Paul Holgado, and Djamila Halliche
58 On the Effect of the Inlet Hydrogen Amount on Hydrocarbons
Distribution Produced via Fischer-Tropsch Synthesis
...........451
Abdelmalek Bellal and Lemnouer Chibane
59 Predictive Current Control in Grid-Connected Fuel
Cell–Photovoltaic Based Hybrid System for Power
Quality Improvement
................................... 459
M. R. Bengourina, L. Hassaine, and M. Bendjebbar
60 Hydrogen Production by Photo Fermentation
viaRhodobacter sp.
..................................... 467
Sabah Menia, Ilyes Nouicer, and Hammou Tebibel
61 Estimation of Hydrogen Production in Three Cities
in the North of Algeria
.................................. 473
Ilyes Nouicer, M. R. Yaiche, Sabah Menia, Fares Meziane,
and Nourdine Kabouche
xii Contents

62 Comparative Study of Different PV Systems Conﬁgurations
Combined with Alkaline and PEM Water Electrolyzers
for Hydrogen Production
................................ 481
Nourdine Kabouche, Fares Meziane, Ilyes Nouicer,
and Raﬁka Boudries
63 Wind Power System for Large-Scale Energy and Hydrogen
Production in Hassi R’mel
............................... 491
Fares Meziane, F. Chellali, K. Mohammedi, Nourdine Kabouche,
and Ilyes Nouicer
64 Analysis and Design of PEM Fuel Cell/Photovoltaic System
to Supply a Trafﬁc Light Signals in Ouargla City Based
on Field Experience
.................................... 499
Abdelmoumen Gougui, Ahmed Djafour, Taha Hamidatou,
S. Eddine Khennour, and Mohammed Bilal Danoune
65 Assessment of Hydrogen Production from Geothermal
Thermoelectric Generator
................................ 507
M. M. Hadjiat, S. Ouali, K. Salhi,
A. Ait Ouali, and E. H. Kuzgunkaya
Author Index
................................................ 515
Contents xiii

Chapter 1
Hydrogen Storage: Different
Technologies, Challenges and Stakes.
Focus on TiFe Hydrides
David Chapelle
, Anne Maynadier, Ludovic Bebon,
and Frédéric Thiébaud
AbstractThe share of renewable energies in the energy mix is gradually increasing.
This transition brings many challenges in the management of electricity grids, espe−
cially because of the ﬂuctuating and intermittent nature of renewable energies. There−
fore, hydrogen represents one of the keystones for the sustainable exploitation of
our energy resources. Hydrogen allows storing in the long term not consumed but
available electricity, and hydrogen is a ‘fuel’ for mobile, nomadic and remote site
applications. Once produced and awaiting consumption, the hydrogen must be stored
in optimal conditions of safety and efﬁciency with regard to the application and its
location. The most mature solution to date is the storage under the compressed form,
which consists in keeping the hydrogen gas in a container at increasing pressures in
order to increase the energy density; cryogenic storage is now well controlled but
generally reserved for very speciﬁc applications for reasons inherent to the tech−
nology and because of signiﬁcant costs; and ﬁnally the so−called ‘solid storage’,
to which the scientiﬁc community has been showing a marked interest for several
decades in the hope of identifying a lasting solution likely to replace advantageously
other solutions. In this paper, these storage media are introduced by evoking their
technological characteristics and their ﬁelds of application often justiﬁed by inherent
limitations of the technology. We will also discuss the challenges still posed by these
storage solutions today by linking them with the research work carried out in the
Department of Applied Mechanics in FEMTO ST Institute.
KeywordsHydrogen storage
·LH2·CGH2·Solid storage·Metal hydride
D. Chapelle (B)·A. Maynadier·L. Bebon·F. Thiébaud
Department of Applied Mechanics, FEMTO ST Institute, Bourgogne Franche−Comté University,
24 Rue de L’Epitaphe, 25000 Besançon, France
e−mail:david.chapelle@univ−fcomte.fr
Federation for Fuel Cell Research FCLAB (FR CNRS 3539), Belfort, France
© The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer
Nature Singapore Pte Ltd. 2021
A. Khellaf (ed.),Advances in Renewable Hydrogen and Other Sustainable Energy
Carriers, Springer Proceedings in Energy,
https://doi.org/10.1007/978−981−15−6595−3_1
1

2 D. Chapelle et al.
1.1 Introduction
For decades, one can read the emergency to act against the climate change, to reduce
drastically our greenhouse gas emission and at the same time to develop a sustainable
management of our energy resources. Undoubtedly, even if it has taken too much
time, the energy transition is occurring in many countries and the part of renew−
able energy in the energy mix is getting greater and greater month after month.
One say, it cannot happen overnight, all the more this new energetic balance comes
with new challenges, especially regarding the management of electricity grids. By
nature, renewable energies have ﬂuctuating and intermittent features but are also
desynchronized between production and consumption. Without any consideration
on technological or cost issues, the previous situation being established, hydrogen
carrier comes as a really promising candidate so as to create synergies between renew−
able energies and hydrogen production and use. Hydrogen allows storing in the long
term not consumed but available electricity, and hydrogen is a ‘fuel’ for mobile,
nomadic and remote site applications. In the ﬁrst case, hydrogen can regulate and
stabilize our electricity distribution networks at different scales; in the second case,
it should progressively replace petroleum products. The recent report [1] of IRENA
(International Renewable Energy Agency) from September 2019, prepared for the
2nd Hydrogen Energy Ministerial Meeting in Tokyo, gives a clear, synthetic but
complete overview of the topic and establishes the analysis of potential pathways to
a hydrogen−enabled clean energy future. It emphasis “Clean hydrogen is enjoying
unprecedented political and business momentum, with the number of policies and
projects around the world expanding rapidly”. As an illustration (Fig.1.1), “the cost
Fig. 1.1Global cost trends for onshore wind and solar PV [1]

1 Hydrogen Storage: Different Technologies, Challenges … 3
of renewable power generation has fallen dramatically in recent years”.
Among all challenges, the hydrogen must be stored safely and efﬁciently with
regard to the application and its location. We list three major media to store hydrogen:
the most mature solution to date is the storage under the compressed form, which
consists in keeping the hydrogen gas in a container at increasing pressures in order to
increase the energy density; cryogenic storage is now well controlled but generally
reserved for very speciﬁc applications for reasons inherent to the technology and
because of signiﬁcant costs; and ﬁnally we identify a third media, the so−called ‘solid
storage’, to which the scientiﬁc community has been showing a marked interest for
several decades in the hope of identifying a lasting solution likely to replace other
solutions, if not advantageously, at least by greatly reducing constraints for the end
user.
Here we discuss these storage media by evoking their technological characteristics
and their ﬁelds of application often justiﬁed by inherent limitations of the technology.
We will also discuss the challenges still posed by these storage solutions by linking
them with the research activities with a speciﬁc focus on hydrogen solid storage.
1.2 Hydrogen Storage Media
Among the various ways to store hydrogen, we decide to pay attention on the three
major solutions. Nowadays, they are the more mature from both a technological and
cost point of view. They are used for decades in various domains of activities.
Because of its high volumetric storage density, the cryogenics or liquid hydrogen
(LH2) has been considered even for automotive implementation till years 2010. Due
to the low required operating temperature, around 20 K, the tank has to be designed in
order to diminish all the more heat exchanges. As illustrated in Fig.1.2,evenifwell
Fig. 1.2Schematic architecture of a liquid hydrogen (LH2) tank including all devices to ensure its
control and monitoring [2]

4 D. Chapelle et al.
Fig. 1.3CGH2 tank
produced by Korean
manufacturer ILJIN [3]
established the architecture of a LH2 tank is undoubtedly the more complex among
all hydrogen storage solutions. It includes some heat exchanger limiting such as an
efﬁcient multi−layer vacuum super insulator (40 layers of metal foil); safety devices
such as safety valve to vent hydrogen gas and prevent gas pressure increase. Due to
unavoidable heat loss, an amount of hydrogen gas is rejected to environment, this
is called boil−off. To complete previous drawbacks, energy balance for LH2 tank is
clearly unfavorable because 30% of the stored chemical energy is required to liquefy
hydrogen.
In comparison, pressurized hydrogen gas consumes less of this stored chemical
energy to be produced: one say 15% for a 700 bar hydrogen compressed gas (CGH2)
and 12% for a 350 bar CGH2. This matter of fact is enough to justify the CGH2
technology is the most suitable for many applications involving hydrogen energy.
Moreover the manufacturing process that is the ﬁlament winding process is perfectly
mastered and machine abilities are fully developed to design any geometry with
high accuracy of ﬁber positioning and the production time also decreases. Figure1.3
shows a commercial CGH2 tank manufactured by the Korean ILJIN. These products
are implemented in fuel cell vehicles.
As mentioned above, the mechanical reinforcement of a CGH2 tank is obtained
by the ﬁlament winding process. The technological state of art leads to manufacture
Type IV (type I is a full metal tank) CGH2 tanks because this technology has proven
to be the unique allowing to store for long term hydrogen and to withstand multiple
emptying and reﬁlling cycles. The reinforcement is here deposited on a polymeric
liner including metallic heads so as to mount ﬁttings. Gravimetric density of 5–6 wt%
may be reached with this technology, considering tank and ﬁttings. Some tricky
challenges remain considering the use of such tanks. Among them, we have to note
the evolution of temperature during ﬁlling, the collapse of the liner during emptying
of hydrogen all the more kinetics is high etc. Some issues are coming from ﬁeld
experience: one expect reﬁlling time to be short but it leads to a potentially critical
increase of temperature, involving to ensure a refreshing of gas before ﬁlling; due to
decrease of pressure, we observe a peeling off between the liner and the composite
part, obviously detrimental for safety reason. Undoubtedly, the CGH2 tank is the

1 Hydrogen Storage: Different Technologies, Challenges … 5
most mature solution considering technology, cost, emptying and reﬁlling kinetics,
nevertheless works are now concentrating on the global efﬁciency, ease of use and
safety.
Solid hydrogen storage in metals allows reaching the higher volumetric density
because mean distance between hydrogen atoms is then the lowest (see Fig.1.4).
Expectedly, due to storage medium the gravimetric density is also the lowest if
the three different media are compared. However, solid storage has undoubtedly
some strong advantages among which it is worth notice the opportunity to choose
the working pressure and temperature according the application (see Fig.1.5).
That means low pressure, between 1 and 10 bar, and temperature, between 10 and
80 °C, are commonly attainable what is particularly attractive for safety reason and
public acceptance. Moreover, the chemical reaction between hydrogen and metals
Fig. 1.4Hydrogen density according the storage medium [4,5]
Fig. 1.5Van’t Hoff plots of some hydrides [6]. Slope relates to the enthalpy of formation

6 D. Chapelle et al.
is exothermic or endothermic during absorption or desorption respectively. The
amount of heat is sufﬁciently high to be managed at all times and necessarily during
desorption if a sufﬁcient hydrogen ﬂow (for fueling a fuel cell, for example) is
required.
As a synthetic consequence of above comments, one say the hydrogen storage
medium is application dependent. High technological application may use LH2 solu−
tion, when hydrogen for mobility, more precisely for automotive, require pressurized
gas, and solid hydrogen is more suitable for stationary applications, eventually for
nomad application.
1.3 TiFe and Its Hydrides
Here we pay attention on solid storage solution, more precisely on Titanium−Iron
alloys which are very good candidate to replace well−known Lanthanum−Nickel
system. The TiFe system has the main advantages to offer a solid solution at lower
cost and more easily available and recyclable in Europe. Figure1.6represents the
phase stability domains of the binary alloy Ti–Fe as a function of temperature and Ti
composition. Two intermetallic compounds exist: FeTi which is of cubic structure
similar to that of CsCl and Fe
2Ti of structure C14 similar to the structure of MgZn2.
Fe
2Ti does not absorb hydrogen, but absorption becomes possible for compounds
that are richer in Ti than TiFe
2according Reilly et al. [7].
These authors studied the Fe–Ti–H system and in particular the reaction between
the TiFe compound and the hydrogen resulting in the formation of two hydrides
TiFeH
1and TiFeH2. Isothermal curves (Pressure−Composition−Isotherm, PCI) give
the hydrogen equilibrium pressure as a function of the amount of hydrogen absorbed
Fig. 1.6Phase diagram of TiFe. Phase stability domains according Ti atomic percentage [8]

1 Hydrogen Storage: Different Technologies, Challenges … 7
by the material at a deﬁned temperature. Figure1.3a shows PCI curve at 40 °C of
TiFe compound from [7] and Fig.1.3b represents PCI curves obtained on TiFeMn0.1
at 8, 22 and 45 °C with our own equipment.
As previously mentioned, when designing a vessel to welcome hydrides, one has
to consider heat exchange to manage the inlet or outlet ﬂow, but also kinetics of
reaction [9,10]. Another challenging issue regarding hydride is the decrepitation
phenomenon that occurs after repeated absorption/desorption cycles. The particle
size of the pristine powder bed decreases while the number of cycles increases. This
is of ﬁrst interest for the designer because distribution inside the vessel consequently
evolves leading to high level of stress on the tank wall and a potential failure [11,
12] (Fig.1.7).
To investigate the phenomenon, we develop speciﬁc observation bench test with
hydrogen reactor and CCD camera to visualize the way particle sizes diminish during
absorption. Figure1.8illustrates the decrepitation of a 2 mm diameter particle of
LaNi
5when submitted to 30 bar hydrogen pressure. The LaNi5is here chosen because
the phenomenon has clearly a higher dynamics with more visible effect on a shorter
time.
In parallel, we carry out Xray tomography analysis of TiFeMn particles at succes−
sive time to evidence the effect of hydrogen on the morphology (see Fig.1.9). This
reveals a fracture network appears due to the hydride phase transformation. The
integrity of the TiFeMn particle is maintained when the fracture network is widely
spread what is directly correlated to mechanical properties of the alloy, more precisely
Fig. 1.7Pressure−composition−isotherm curves of TiFe alloys;aHysteresis in the TiFe–H system
at 40 °C according [7],bTiFeMn alloy characterized at 8, 22 and 45 °C on our bench test

8 D. Chapelle et al.
Fig. 1.8Focusona2mmLaNi 5particle size during absorption at different time:ainitial,bafter
2h,c4handd6h
Fig. 1.9X−ray tomography
of a TiFeMn particle after a
20 h exposure to hydrogen

1 Hydrogen Storage: Different Technologies, Challenges … 9
resilience. This respond seems really different of the respond of LaNi5alloy (see
Fig.1.8) for which energetic expulsion of very small particles is observed.
These observations, brieﬂy introduced here, feed our reﬂections and our modeling
to predict the behavior of the single particle but also the particle in the powder bed.
The Different Element Modeling is peculiarly convenient for such mechanical issue,
and we presently develop routines for YADE [13] to simulate the particle response
depending on mechanical parameters.
1.4 Conclusion
In a world where renewable energies have to become the rule, hydrogen beneﬁts
a high potential in order to store electricity under gas form for long term and thus
answers main drawbacks of these energies, that are their intermittence and ﬂuctuating
nature. We introduced the three main hydrogen storage media: liquid hydrogen LH2,
pressurized hydrogen CGH2 and solid storage solutions. Considering the state of art,
these solutions are rather mature, even if at different stages. The disadvantages but
also the domains of application were recalled. As an illustration, a focus was made
on the research activities at the Department of Applied Mechanics in Besançon
that is the decrepitation phenomenon of metal hydride occurring while the material
is submitted to repeated hydrogen cycles. We aim at increasing knowledge and at
modeling the decrepitation in order to develop methodologies and tools to be used
when designing solid storage tank.
References
1. IRENA, Hydrogen: a renewable energy perspective 2019.https://www.irena.org/−/media/Files/
IRENA/Agency/Publication/2019/Sep/IRENA_Hydrogen_2019.pdf
2. The Linde Group, Wiesbaden
3. ILJIN Group, Seoul
4. U. Eberle, G. Arnold, R. von Helmolt, Hydrogen storage in metal–hydrogen systems and their
derivatives. J. Power Sources154(2), 456–460 (2006)
5. U. Eberle, G. Arnold, R. von Helmolt, Fuel cell vehicles: status 2007. J. Power Sources165(2),
833–843 (2007)
6. Zuttel, A.: Materials for hydrogen storage. materialstoday6(9), 24–33 (2003)
7. J.J. Reilly, R.H. Wiswall, Jr., Formation and properties of iron titanium hydride, Inorg. Chem.
13, 218–222 (1974)
8. H. Okamoto,Phase Diagrams for Binary Alloys, 2nd edn. (ASM International, Ohio, 2000)
9. A. Zeaiter, D. Chapelle, F. Cuevas, A. Maynadier, M. Latroche, Milling effect on the microstruc−
tural and hydrogenation properties of TiFe
0.9Mn0.1alloy. Powder Technol.339, 903–910
(2018)
10. C. Lexcellent, G. Gay, D. Chapelle, Thermomechanics of a metal hydride−based hydrogen tank.
Continuum Mech. Thermodyn.27, 379–397 (2015)
11. K. Nasako, Y. Ito, N. Hiro, M. Osumi, Stress on a reaction vessel by the swelling of a hydrogen
absorbing alloy. J. Alloy. Compd.264, 271–276 (1998)

10 D. Chapelle et al.
12. Qin, F.: Pulverization, expansion of La
0.6Y0.4Ni4.8Mn0.2during hydrogen absorption–desorp−
tion cycles and their inﬂuences in thin−wall reactors. Int. J. Hydrogen Energy33, 709–717
(2008)
13. V. Šmilauer et al.,Yade Documentation, 2nd edn. The Yade Project (2015).https://doi.org/10.
5281/zenodo.34073.http://yade−dem.org/doc/

Chapter 2
Preparation of ZrO2–Fe2O3
Nanoparticles and Their Application
as Photocatalyst for Water Depollution
and Hydrogen Production
M. Benamira
, N. Doufar, and H. Lahmar
AbstractThis study is deducted to the treatment of wastewater from the organic
pollutants and hydrogen production using a photocatalyst composed of Fe
2O3and
ZrO
2. The structural and photophysical properties of the catalysts have been charac-
terized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer–
Emmett–Teller (BET) and UV–Vis diffuse reﬂectance spectrometry. The photocata-
lyst acquiredptype conductivity, due to oxygen insertion in the layered lattice with
an activation energy of 0.15 eV. The ﬂat band potential (E
fb,−0.44 VSCE), close to
the photocurrent onset potential (−0.2 V
SCE). A total degradation of Methyl orange
is achieved within 90 min under sunlight irradiation. The total degradation of phenol
is also achieved in less than 120 min. Based on the energy band positions, the detailed
reaction mechanism has been discussed. The position of the conduction band in the
energy diagram shows the possibility of H
2production under visible light.
KeywordsPhotocatalytic activity
·ZrO2–Fe2O3·DRX
2.1 Introduction
Zirconia, ZrO2, is a ceramic material with a property-structure dependence. For
that, by playing on the structure with judicious additions or by using the appropriate
preparation method, it is possible to modify its properties of use to make it a functional
material used in various applications. Zirconia has a wide variety of application due
to its ﬂexible structural characteristics [1–4]. This ﬂexibility allows new areas of
functional applications to emerge.
M. Benamira (B)·N. Doufar
Laboratory of Materials Interaction and Environment (LIME), University of Mohamed Seddik
Benyahia, BP 98 Ouled Aïssa, Jijel, Algeria
e-mail:[email protected];[email protected]
H. Lahmar
University of Mohamed Seddik Benyahia, BP 98 Ouled Aïssa, Jijel, Algeria
© The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer
Nature Singapore Pte Ltd. 2021
A. Khellaf (ed.),Advances in Renewable Hydrogen and Other Sustainable Energy
Carriers, Springer Proceedings in Energy,
https://doi.org/10.1007/978-981-15-6595-3_2
11

12 M. Benamira et al.
Our main objective in this work is to study a photocatalytic process for water
treatment as an alternative to existing processes using the sun. This work consists in
synthesizing new material based on zirconia that can be used in water depollution.
Our choice is focused on the ZrO
2–Fe2O3system. The addition of Fe increases the
catalytic activity of zirconia for hydrocarbon isomerization reactions. However, the
addition of ZrO
2increases the catalytic activity of Fe2O3by increasing the stability
of the Fe
3+
cation. Catalysts based on the Fe2O3–ZrO2system are also used in
ammonium synthesis, Fischer-Tropic synthesis and carbon monoxide hydrogenation.
Iron as a dopant was able to stabilize cubic zirconia, c-ZrO
2, but due to its smaller
ionic radius compared to the rare earth cations, this stabilization is not effective.
In this work, we were interested in the synthesis of Fe-doped ZrO
2material by co-
precipitation for the degradation of organic pollutants and also for the production of
H
2under visible light.
2.2 Experimental
Fe-doped ZrO2(3 g) was synthesized by co-precipitation using ZrOCl2∙8H2O
(99.5%; Sigma–Aldrich), FeCl
3∙6H2O (97%; Sigma–Aldrich) and NH4OH as
starting materials. The starting reagents were mixed according to the following
equation:
(1−x)ZrOCl
2·8H2O+xFeCl 3·6H2O
+(2+x)NH
4OH→Zr (1−x)FexO(2−x/2) +(2+x)NH 4Cl
+18 H
2O(x=2/3) (2.1)
3.255 g of ZrOCl
2∙8H2O was dissolved in distilled water (100 mL) and stirred vigor-
ously for 40 min. After that, 5.46 g of FeCl
3∙6H2O were added to the ﬁrst solution.
The aqueous suspensions were mixed and stirred slowly for 60 min at 65 °C. NH
4OH
(3.5 M) was added dropwise under continuous stirring for 60 min to adjust the pH
solution at 10, and to form a solid precipitate with a brown color. The resulting
mixture was centrifuged for 15 min; the obtained precipitate was ﬁltered and washed
several times with deionized water. After that, the resulting precipitate was dried
in an oven at 100 °C for 24 h and calcined at 600 °C for 3 h. TiO
2powder used
in the hetero-junction was synthesized as reported in our previous work [5]. The
hetero-junction ZrFe
2O5/TiO2was obtained by mixing both catalysts in the mass
ratio (1/1).
X-ray diffraction (XRD) was used to characterize the structure of the as prepared
powders. The patterns were obtained using a Brüker “D8 Advance” powder diffrac-
tometer with a Cu Kαradiation (λ=1.54056 Å) and 2θvarying from 20 to 80° by
steps increments of 0.0146° and 0.2 s counting time per step. The Scanning Electron
Microscopy (SEM) was performed on a FEG-SEM JEOL 7600 in order to evaluate
the size distribution as well as the morphology of the nanoparticles. The FT-IR spectra

2 Preparation of ZrO2–Fe2O3Nanoparticles and Their Application … 13
were recorded on a VERTEX 70/70v spectrophotometer (BRUKER) in transmission
mode between 400 and 4000 cm
−1
. The UV–vis diffuse reﬂectance spectra were
obtained with a UV-visible spectrophotometer (Specord 200 Plus). The BET surface
areas of the powders were carried out on a Micromeritics 3Flex analyzer deter-
mined by N
2adsorption–desorption isotherm measurement at−196 °C. The electro-
chemical characterization was performed in 0.1 M Na
2SO4electrolyte using a stan-
dard three-electrode cell using Solartron 1287 potentiostat and frequency response
analyzer Solartron 1260; the sweep rate was set at 5 mV s
−1
. The working electrode
is prepared as 10 mm diameter pellet using uniaxial pressure of 3.5 MPa and sintered
at 600 °C for 2 h. It was introduced into resin epoxy, polished with SIC paper (1200)
and washed with water. The electrical contact was achieved by the painted silver
lacquer. The photocatalytic tests were conducted in May and June between 9 am and
5 pm. The sunlight irradiation was evaluated as 700 W/m
2
, while the temperature
averaged 28 °C. The photocatalytic tests were carried out in an open Pyrex glass
reactor with a double wall. Before irradiation, the suspensions composed of 50 mL
of organic pollutant, 50 mg of catalyst and H
2O2(10
−5
M) were kept in the dark for
60 min under magnetic stirring to ensure good adsorption equilibrium on the cata-
lyst surface. Then, the reactor was exposed to solar irradiation. The absorbance was
measured with a UV-visible spectrophotometer (Shimadzu UV-2400). After irradia-
tion, the solutions were centrifuged and ﬁltered through a membrane ﬁlter in order
to measure the decomposition rate. The production of H
2by photocatalysis was
carried out at 50 °C [6]. The photocatalyst powder (100 mg) was introduced in a
Pyrex reactor equipped with a cooling system and dispersed in 200 mL of Na
2S2O3
solution. Before each test, O2was purged by passing N2for 20 min. Three tungsten
lamps with a total intensity of 30 mW cm
−2
were used as the light source. Hydrogen
gas was identiﬁed by gas chromatography using Clarus® 680 GC PerkinElmer Gas
Chromatograph and the volume of H
2was quantiﬁed in a water manometer.
2.3 Results and Discussion
2.3.1 Characterization of Material
Figure2.1a shows the XRD pattern of ZrFe 2O5synthesized by co-precipitation.
The substitution of Zr by Fe conﬁrms the formation of the tetragonal solid solution
Zr
1−xFexO2−x/2in agreement with JCPDS Card N° 17-0923. The incorporation of
high Fe content reveals the presence of new peaks of the hematite (α-Fe
2O3,JCPDS
N° 01-1053) and conﬁrms the results obtained by Davison et al. [7] and Botta et al. [8].
The substitution of Zr
4+
by Fe
3+
ions in the ZrO2lattice was reported using different
preparation methods. These studies conﬁrm the formation of tetragonal phase at low
Fe
3+
concentrations (<10 at.%). However, for high Fe
3+
content (>20 at.%), the XRD
patterns indicate the presence ofα-Fe
2O3phase in total agreement with our results.

14 M. Benamira et al.
Fig. 2.1 aPowder X-ray diffraction results of ZrFe2O5powder.bScanning electron microscopy
of ZrFe2O5powder
Fig. 2.2FT-IR spectra of
ZrFe2O5prepared by the
co-precipitation method
4000 3000 2000 1000
ZrFe
2
O
5
Abs. (u.a)
Wavenumber ( cm
-1
)
The infrared Fourier transform spectrum is illustrated in Fig.2.2; the wide band at
3400 cm
−1
is attributed to the folding mode of OH groups due to adsorbed water on
the powder surface. The peaks observed below 750 cm
−1
are attributed to the Fe–O
and Zr−O stretching vibrations while the peaks at 1470 and 1560 cm
−1
are assigned
to adsorbed water molecules. A weak peak at 2315 cm
−1
is assigned to adsorbed
carbon dioxide when the sample was handled in air [9,10].
The converted UV-visible absorption data are used to evaluate the optical band
gap (Eg) by extrapolating the linear portion of the plots (αhν)
2
versus hνto (αhν)
2
=0. The optical band gap of the as-prepared powder is 1.74 eV.

2 Preparation of ZrO2–Fe2O3Nanoparticles and Their Application … 15
2.3.2 Photocatalytic Activity
The ZrFe2O photocatalyst was used for the degradation of the azo dye methyl orange
and the organic compound phenol under solar light irradiation.
The standard redox potential of
•
OH radical (+2.8 V) classiﬁes it as a powerful
oxidizing agent, able to oxidize the majority of organic compounds into mineral
end products. An initial concentration of 30 mg/L was used for the two products
tested (phenol and methyl orange); Fig.2.3summarizes the kinetic results of the
degradation in the presence of H2O2under solar light irradiation. The two pollutants
are totally degraded after 90 min for methyl orange (30 mg/L) and 120 min for phenol
(30 mg/L). The results obtained in this study are promising compared to that those
reported in the literature. Murcia et al. [11] studied the photocatalytic degradation of
methyl orange and phenol over TiO2and Pt–TiO2. Total elimination of phenol and
methyl orange was obtained after 2 h under UV light; while degradation of only 60%
of phenol within 2 h under sunlight irradiation was obtained by Al-Hamdi et al. [12].
The relevant reactions of photocatalysis mechanism occur at the surface of the
photocatalyst causing the degradation of these two organic compounds (OC) can be
expressed as follows:
ZrFe2O5+hv→ZrFe2O5
→
e
−
CB
+h
+
VB

(2.2)
ZrFe2O5+
→
h
+
VB

+H2O→ZrFe2O5+H
+
+OH
−
(2.3)
ZrFe2O5+
→
h
+
VB

+OH
−
→ZrFe2O5+
•
OH (2.4)
ZrFe2O5+
→
e
−
CB

+O2→ZrFe2O5+O
•−
2
(2.5)
Fig. 2.3Degradation of
methyl orange and phenol by
ZrFe2O5catalyst in the
presence of H2O2~
0.2 mL/L,T=25 °C, pH=
7, catalyst dose=1 mg/mL)
under solar light irradiation
0
30
60
90
120
0
20
40
60
80
100
Methylorange
Phenol
Time (min)
Degradation (%)

16 M. Benamira et al.
O
•−
2
+H
+
→HO
•−
2
(2.6)
2HO
•
2
→H2O2+O
•−
2
(2.7)
H2O2+
→
e
−
CB
θ
→
•
OH+OH
−
(2.8)
OC+OH
•
/O
•−
2
→(Degradation products)CO2+H2O (2.9)
The use of the hetero-junction system is one of the effective ways to improve
the photocatalytic activity under visible light irradiation. The new hetero-junction
ZrFe2O5/TiO2with a mass ratio (1/1) was used for the H2production. Figure2.4a
presents the current density-potential J(V) characteristics of ZrFe2O5at pH ~ 7. The
cathodic reduction potential of water (production of H2) appears at−0.16 VSCEand
Fig. 2.4 aThe intensity
potential J(V) characteristic
of ZrFe2O5
(Inset-Semi-logarithmic plot
over ZrFe2O5electrode).
bVolume of evolved H2
versus illumination time with
ZrFe2O5: (1) with Methyl
orange, (2) without Methyl
orange
-0.30 -0.15 0.00 0.15 0.30 0.45
-100
-75
-50
-25
0
25
50
(a)
-0,2 -0,1 0,0 0,1 0,2 0,3 0,4 0,5
-2
-1
0
1
2
log (J ) ( A/cm
2
)
Potential (V/
ECS
)
E
H2O/H2
= -0.16 V
Potential (V/SCE)
J
(
A/cm
2
)
B
0 102030405060
0
10
20
30
40
50
60
(b)
(1) (2)VH
2
( mol)
Time (min)

2 Preparation of ZrO2–Fe2O3Nanoparticles and Their Application … 17
corresponds to the intercept point of current density curve with the potential-axis.
The anodic oxidation potential of water appears at 0.3 V
SCE(Inset Fig.2.4a). The
volume of H
2obtained with Methyl orange increased compared to ZrFe2O5alone
by 60% (Fig.2.4b).
2.4 Conclusion
The degradation of organic pollutants by ZrFe2O5under solar light irradiation
conﬁrms the high photocatalytic efﬁciency. The use of p-n hetero-junction improves
the photocatalytic activity of H
2production by enhancing the separation of electron-
hole pairs and reduces the recombination process. The photocatalytic mechanism of
the degradation was proposed. A total photodegradation of methyl orange and phenol
was obtained in less than 120 min.
References
1. M.H. Khajezadeh, M. Mohammadi, M. Ghatee, Hot corrosion performance and electrochemical
study of CoNiCrAlY/YSZ/YSZ-La
2O3multilayer thermal barrier coatings in the presence of
molten salt. Mater. Chem. Phys.220, 23–34 (2018)
2. M. Benamira, A. Ringuede, M. Cassir, D. Horwat, J.F. Pierson, P. Lenormand, J. Fullen-
warth, Comparison between ultrathin ﬁlms of YSZ deposited at the solid oxide fuel cell
cathode/electrolyte interface by atomic layer deposition, dip-coating or sputtering. Open Fuels
Energy Sci. J.2(1), 87–99 (2009)
3. M. Benamira, A. Ringuedé, M. Cassir, D. Horwat, P. Lenormand, F. Ansart, J.P. Viri-
celle, Enhancing oxygen reduction reaction of YSZ/La
2NiO4+δusing an ultrathin La2NiO4+δ
interfacial layer. J. Alloy. Compd.746, 413–420 (2018)
4. E. Lay, M. Benamira, C. Pirovano, G. Gauthier, L. Dessemond, Effect of Ce-doping on the
electrical and electrocatalytical behavior of La/Sr chromo-manganite perovskite as new SOFC
anode. Fuel Cells12, 265–274 (2012)
5. N. Doufar, M. Benamira, H. Lahmar, M. Trari, I. Avramova, M.T. Caldes, Structural and
photochemical properties of Fe-doped ZrO
2and their application as photocatalysts with TiO2
for chromate reduction. J. Photochem. Photobiol. A386, 112105 (2020)
6. H. Lahmar, M. Trari, Photocatalytic generation of hydrogen under visible light on La
2CuO4.
Bull. Mater. Sci.38(4), 1043–1048 (2015)
7. S. Davison, R. Kershaw, K. Dwight, A. Wold, Preparation and characterization of cubic ZrO
2
stabilized by Fe (III) and Fe (II). J. Solid State Chem.73, 47–51 (1988)
8. S.G. Botta, J.A. Nav´ıo, M.C. Hidalgo, G.M. Restrepo, M.I. Litter, Photocatalytic properties of
ZrO
2and Fe/ZrO2semiconductors prepared by a sol–gel technique. J. Photochem. Photobiol.
AChem.129, 89–99 (1999)
9. S. Douafer, H. Lahmar, M. Benamira, G. Rekhila, M. Trari, Physical and photoelectrochemical
properties of the spinel LiMn
2O4and its application in photocatalysis. J. Phys. Chem. Solids
118, 62–67 (2018)
10. S. Douafer, H. Lahmar, M. Benamira, L. Messaadia, D. Mazouzi, M. Trari, Chromate reduc-
tion on the novel hetero-system LiMn
2O4/SnO2catalyst under solar light irradiation. Surf.
Interfaces17, 100372 (2019)

18 M. Benamira et al.
11. J.J. Murcia, M.C. Hidalgo, J.A. Navío, J. Araña, J.M. Doña-Rodríguez, Correlation study
between photo-degradation and surface adsorption properties of phenol and methyl orange on
TiO
2vs platinum-supported TiO2.Appl.Catal.B150, 107–115 (2014)
12. A.M. Al-Hamdi, M. Sillanpää, J. Dutta, Photocatalytic degradation of phenol by iodine doped
tin oxide nanoparticles under UV and sunlight irradiation. J. Alloy. Compd.618, 366–371
(2015)

Chapter 3
Preparation of Anode Supported Solid
Oxide Fuel Cells (SOFCs) Based
on BIT07 and Pr
2NiO4+δ: Inﬂuence
of the Presence of GDC Layer
M. Benamira
, M. T. Caldes, O. Joubert, and A. Le Gal La Salle
AbstractIn this work, we study the electrochemical performance of anode
supported solid oxide fuel cells (SOFCs) based on perovskite-type materials:
BaIn
0.3Ti0.7O2.85(BIT07) as an electrolyte, BIT07-Ni as a cermet anode and
Pr
2NiO4+δas a cathode. Anode/electrolyte assemblies have been prepared by tape
casting and co-ﬁring and the cathode has been deposited by screen-printing. The
performance of BIT07-Ni/BIT07/Pr
2NiO4+δcells has been determined between 600
and 750
°
C under humidiﬁed (3% H2O) hydrogen as fuel and air as oxidant. The pres-
ence of an interfacial layer of gadolinia doped ceria (GDC) is also tested. Impedance
Spectroscopy (EIS) measurements have also been carried out and allowed to differen-
tiate between the series and polarization resistances. The power density obtained from
the cell with GDC was 119.21 mW/cm
2
at 700 °C, compared with 28.1 mW/cm
2
for
the cell without GDC thin layer. These results conﬁrmed that the presence of a dense
thin layer of GDC at the interface electrolyte/cathode is a very promising method for
intermediate temperature SOFCs (IT-SOFCs) to increase the performance.
KeywordsTape casting
∙SOFC∙EIS∙Pr2Nio4+δ
3.1 Introduction
Nowadays, solid oxide fuel cells (SOFCs) operate at 800–1000 °C. Reducing the
operating temperature of solid oxide fuel cells requires the development of new elec-
trolyte materials with good performance at intermediate temperatures (500–700 °C).
BaIn
0.3Ti0.7O2.85(BIT07) has the required transport properties and redox stability to
be considered as a promising electrolyte material with an ionic conductivity of 10
−2
M. Benamira (B)
Laboratory of Materials Interaction and Environment (LIME), University of Mohamed Seddik
Benyahia, BP 98 Ouled Aïssa, Jijel, Algeria
e-mail:[email protected];[email protected]
M. Benamira∙M. T. Caldes∙O. Joubert∙A. Le Gal La Salle
Institut Des Matériaux Jean Rouxel (IMN), Université de Nantes, CNRS, 2, rue de la Houssinière,
BP 32229, 44322 Nantes Cedex 3, France
© The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer
Nature Singapore Pte Ltd. 2021
A. Khellaf (ed.),Advances in Renewable Hydrogen and Other Sustainable Energy
Carriers, Springer Proceedings in Energy,
https://doi.org/10.1007/978-981-15-6595-3_3
19

20 M. Benamira et al.
Scm
−1
at 700 °C and chemical stability under a wide range of partial pressures of
oxygen [1–4]. The praseodymium nickelate Pr
2NiO4+δ(so-called PNO) is a mixed
ionic electronic conducting (MIEC) oxide widely studied as oxygen electrode for
solid oxide fuel cells and solid oxide electrolysis cells (SOEC) as well. MIEC oxide
attracted particular attention since the oxygen reduction reaction (ORR) has been
extended to the whole volume of the electrode, compared to a pure electronically
conducting cathode where the ORR is restrained to the triple phase boundary (TPB)
points located at the cathode/electrolyte interface [5–9].
This paper aims to study the inﬂuence of the presence of the material used as
an interlayer between the PNO electrode and the BIT07 electrolyte on the electro-
chemical performance of the SOFC. Ce
0.8Gd0.2O1.9(namely GDC) has been selected
as interlayer material. It has also been demonstrated that BIT07 can be used with well-
known cathode materials, such as La
0.58Sr0.4Co0.2Fe0.8O3−δ(LSCF) or Nd2NiO4+δ,
and that best results regarding electrochemical performance have been obtained with
LSCF.
Our main objective in this work is to prepare a complete Ni-BIT07/BIT07/PNO
and Ni-BIT07/BIT07/GDC//PNO cells by tape casting and screen printing. They have
been tested under air on the cathode side and wet H
2(3% H2O) on the anode side.
The performance has been discussed in terms of total resistance determined from
current density/voltage curve (J/U) and Electrochemical Impedance Spectroscopy
(EIS) measurements at the Open Circuit Voltage (OCV) to understand the origin of
this resistance, and to determine the relevant parameters that can be modiﬁed in order
to minimize it. The stability of the cell presenting the highest performance has been
studied at the operating temperature of 700 °C.
3.2 Experimental
BaIn0.3Ti0.7O2.85(BIT07) was synthesised by solid state reaction by using stoichio-
metric amounts of BaCO
3(Alfa Aesar), In2O3(Alfa Aesar) and TiO2(Merck). Reac-
tants were thoroughly mixed using acetone in an agate mortar and calcined at 1200 °C
for 24 h. The obtained powder was again ground well, mixed, pressed into disks and
sintered at 1350 °C for 24 h, ground and passed through mesh 100. Pr
2NiO4+δpowder
was provided by Marion Technologie and NiO powder (grain size 0.5–1μm) was
provided by Pharmacie Centrale de France. X-ray diffraction (XRD) was used to
characterize the structure of the as-prepared powders. The patterns were obtained
using a Brüker “D8 Advance” powder diffractometer with a Cu Kαradiation (λ=
1.54056 Å) and 2θvarying from 20 to 80° by steps increments of 0.0146° and 0.2 s
counting time per step. The Scanning Electron Microscopy (SEM) was performed
on a FEG-SEM JEOL 7600. By Brunauer–Emmett–Teller (BET), the surface areas
of the powders were measured and carried out on a Micromeritics 3Flex analyzer
determined by N
2adsorption–desorption isotherm measurement at−196°C.
Before cell fabrication and in order to decrease the grain sizes, the as-prepared
powders of BIT07 were ball-milled at 500 rpm: 60 h. The anode composition has been

3 Preparation of Anode Supported Solid Oxide Fuel Cells (SOFCs) … 21
Fig. 3.1Preparation of Ni-BIT07/BIT07/PNO anode supported cell.aAnode of BIT07-NiO,
belectrolyte BIT07,cdeposition of PNO cathode,dcurrent collector of gold grid
optimized to reach the best electrochemical performance, obtained with a BIT07-
Ni cermet (BIT07:NiO 50:50 wt%), realized with a BIT07 powder ball-milled and
5 wt% CB as pore forming agent. The button cell (Ø 10 mm) is composed of an
anode supported electrolyte/anode half-cell, prepared by tape casting and co-ﬁred.
Then a PNO cathode is deposited on the electrolyte by screen-printing (Fig.3.1).
Current collectors, made of discs (5 mm in diameter) of gold grid (Goodfellow,
wire diameter: 60μm) are attached on both the electrodes using gold ink. The cell is
placed at 120 °C for overnight to evaporate the solvents and to obtain good electrical
contacts. The current–voltage characteristic is measured with the use of a laboratory-
made testing system. The cell was sealed on the top of an alumina sample tube. Thus
separating the atmospheres between the inside and outside of the tube. The fuel-gas
supply tube is situated inside the sample tube. The system was kept vertically in a
tubular furnace. The measurements of current density (J) and voltage (U) were done
by digital multimeters Keithley 197 and Protek 506, respectively. Current drawn in
the circuit was varied using a rheostat. Prior to the measurements, nickel oxide is
reduced in situ at 700 °C for 2 h under wet H
2and measurements were made at
700 °C, under wet (3% H
2O) H2on the anode side, and air on the cathode side.
Electrochemical performances of single cells were studied by electrochemical
impedance spectroscopy (EIS). The measurements were realized using a frequency
response analyzer Solartron 1260. The impedance spectra were recorded over a
frequency range 2 MHz to 0.01 Hz with a signal amplitude of 10 mV and with
10 points per decade under open circuit conditions from 500 to 700 °C. The EIS
diagrams were normalized to the electrode area and ﬁtted using equivalent circuits
with the ZView
®
software (Scribner Associates). Post mortem (after measurements)
analyses of the cells have been carried out by SEM, using a JEOL 7600.

22 M. Benamira et al.
Fig. 3.2Performance of a single cell consisting in:aNi-BIT07/BIT07 and Pr 2NiO4+δsintered at
1050 °C,bNi-BIT07/BIT07 and Pr
2NiO4+δsintered at 1100 °C as the cathode; I-V curves and
resulting power densities
3.3 Results and Discussion
3.3.1 Characterization of Material
Figure3.2presents the voltage (U) and power density (P) versus current density
(J) characteristics obtained for two single cells at different temperatures 1050 and
1100 °C, respectively, Fig.3.2a, b. In both cases, the polarisation curves (U/J) are
clearly linear in the studied current density range. In both cases, the OCV is lower than
the theoretical value expected, suggesting a small leakage between gas chambers.
Table3.1gathers the cells characteristics obtained from the voltage and power density
versus current density characteristics and also from the Nyquist diagrams of the single
cells.
The extrapolated maximum power densities are of about 28.1 and 22.06 mW cm
−2
for the two cells, respectively. The ASR value obtained from the EIS measurements,
10.41 for cells A at 700 °C, is in agreement with the ones obtained from the U/J
Table 3.1Characteristics of the cell Ni-BIT07/BIT07 and Pr2NiO4+δsintered at 1050 °C recorded
at OCV, ASR(U/J) calculated from U/J curves, ASR(EIS), Rs and Rp obtained from the EIS
measurements
T(°C)OCV (V)Pmax(mW cm
−2
)ASR(U-J)(δcm
2
)ASR(Nyquist)
(δcm
2
)
Re.S
(δcm
2
)
Rp.S
(δcm
2
)
600 0.8754.83 41.34 43.39 3.46
(7.4%)
39.93 (92.6%)
650 0.8439.85 18.81 20.27 2.20 (9.8%)18.07 (90.2%)
700 0.91422.06 9.75 10.41 1.01 (8.8%)9.40 (91.2%)
750 0.90044.13 4.64 5.63 1.14 (16.8%)4.49 (83.2%)

3 Preparation of Anode Supported Solid Oxide Fuel Cells (SOFCs) … 23
Fig. 3.3X-ray diffraction patterns of BIT07/Pr2NiO4+δcomposite pellets that were calcined at
1100 °C for different times
curves, 9.95. Those values are too high with a major contribution of polarization
resistance (91.2%) and need more improvement. Thus indicates that the polarization
resistance played an important role in cell performance.
In order to understand the origin of the low performances of the two cells, the reac-
tivity test between BIT07 and Pr
2NiO4+δpowders for more than 168 h at 1100 °C
was done as shown in Fig.3.3. Indeed, the DRX analysis reveals the signiﬁcant pres-
ence of a new phase (Pr
1,6Ba0,4NiO4) due to the reaction between the electrolyte and
cathode. Considering the reactivity of the Pr
2NiO4+δwith BIT07, the higher power
densities would expect to be achieved by using a thin interfacial layer of GDC.
A thin interfacial layer (5μm) of GDC is deposited to the electrolyte/anode
half-cell by screen-printing and co-ﬁred at 1350 °C for 8 h. Then a PNO cathode
is deposited on the electrolyte by screen-printing. To demonstrate the beneﬁt of
incorporating a thin layer at the interface between the electrode and electrolyte, the
I–V–P curves of the fuel cell are shown in Fig.3.4. The power density obtained from
the cell with GDC thin ﬁlm was about 119.21 mW/cm
2
at 700 °C, compared with
about 28.1 mW/cm
2
for the cell without thin ﬁlm.
3.4 Conclusion
In this work, anode supported cells based on BIT07 as an electrolyte, BIT07-Ni as
anode and Pr
2NiO4+δas cathode have been successfully realized by tape casting and
screen-printing. The reactivity test between BIT07 and Pr
2NiO4+δpowders reveals
the presence of a new phase (Pr
1,6Ba0,4NiO4) which explain the low performances
of the single cell. The power density of a single cell with GDC thin ﬁlm at the

24 M. Benamira et al.
Fig. 3.4 aPerformance of a single cell consisting in Ni-BIT07/BIT07/GDC/Pr2NiO4+δ; I-V curves
and resulting power densities,bscanning electron microscope image (cross-section) of single cell
interface electrolyte/cathode was signiﬁcantly higher than that of a single cell without
interfacial layer. This is attributed to increased interfacial area. The factors such as the
better electrocatalytic activity of ceria and the intrinsic properties of nanostructured
thin ﬁlms.
References
1. F. Moser, M.T. Caldes, M. Benamira, J.M. Greneche, P. Leone, O. Joubert: Development of new
anodes compatible with the solid oxide fuel cell electrolyte BaIn
0.3Ti0.7O2.85.J.PowerSour
201, 103–111 (2012)
2. M. Benamira, M. Letilly, E. Quarez, O. Joubert, A.L.G. La Salle, Optimization of SOFC
anode/electrolyte assembly based on BaIn
0.3Ti0.7O2.85(BIT07)/Ni-BIT07 using an interfacial
anodic layer. J. Power Sour.251, 66–74 (2014)
3. M. Benamira, L. Thommy, F. Moser, O. Joubert, M.T. Caldes, New anode materials for IT-
SOFC derived from the electrolyte BaIn0.3Ti0.7O2.85 by lanthanum and manganese doping.
Solid State Ionics265, 38–45 (2014)
4. M. Letilly, A. Le Gal La Salle, M. Caldes, M. Marrony, O. Joubert, Validation of
BaIn
0.3Ti0.7O2.85as SOFC electrolyte with Nd2NiO4, LSM and LSCF as cathodes. Fuel Cells
9, 622–629 (2009)
5. E. Lay, M. Benamira, C. Pirovano, G. Gauthier, L. Dessemond, Effect of Ce-doping on the
electrical and electrocatalytical behavior of La/Sr chromo-manganite perovskite as new SOFC
anode. Fuel Cells12, 265–274 (2012)
6. M. Benamira, A. Ringuedé, M. Cassir, D. Horwat, P. Lenormand, F. Ansart, J.P. Viri-
celle, Enhancing oxygen reduction reaction of YSZ/La
2NiO4+δusing an ultrathin La2NiO4+δ
interfacial layer. J. Alloy. Compd.746, 413–420 (2018)
7. M.T. Caldes, K.V. Kravchyk, M. Benamira, N. Besnard, O. Joubert, O. Bohnke, N.
Dupré, Metallic nanoparticles and proton conductivity: improving proton conductivity of
BaCe
0.9Y0.1O3-δand La0.75Sr0.25Cr0.5Mn0.5O3-δby Ni-doping. ECS Trans45, 143–154 (2012)
8. J.M. Bassat, M. Burriel, O. Wahyudi, R. Castaing, M. Ceretti, P. Veber, J.A. Kilner, Anisotropic
oxygen diffusion properties in Pr
2NiO4+δand Nd2NiO4+δsingle crystals. J. Phys. Chem. C
117, 26466–26472 (2013)
9. C. Allançon, A. Gonthier-Vassal, J.M. Bascat, J.P. Loup, P. Odier, Inﬂuence of oxygen on
structural transitions in Pr
2NiO4+δ. Solid State Ionics74, 239–248 (1994)

Chapter 4
Preparation of the Spinel CuCo2O4
at Low Temperature. Application
to Hydrogen Photoelectrochemical
Production
R. Bagtache
, K. Boudjedien, I. Sebai, D. Meziani, and Mohamed Trari
AbstractWe reported for the ﬁrst time a facile method for the preparation of the
spinel CuCo
2O4at 140 °C by using sulfates of copper and cobalt in KOH. The
compound crystallizes in a cubic system (SG: F d¯3 m) with a lattice constant of
8.0590 Å. The material was characterized by physical and photo-electrochemical
techniques. The X-ray diffraction (XRD) pattern conﬁrms the single phase with a
high purity. The UV–Visible spectroscopy of the black product revealed a direct
optical transition of 1.38 eV. The capacitance-potential (C
−2
-E) displays a negative
slope and a ﬂat band potential (+0.28 V
SCE) characteristic ofp-type semiconductor
behavior. Further, the Nyquist plot shows a semicircle followed by straight line at low
frequencies, indicating a diffusion process. To show effectively the photocatalytic
performance, we tested our product in the hydrogen production upon visible light
irradiation. H
2evolution rate of 7μmol h
−1
mg
−1
and a quantum efﬁciency of 1.1%
were obtained upon visible light illumination.
KeywordsSpinel CuCo
2O4·Photo-electrochemical characterization·Hydrogen·
Visible light
4.1 Introduction
Nowadays, many efforts have been devoted in the ﬁeld of environment which consists
to develop new processes for the puriﬁcation of air and treatment of water [1]. In this
R. Bagtache (B)·K. Boudjedien·D. Meziani
Faculty of Chemistry, Laboratory of Electrochemistry-Corrosion, Metallurgy and Inorganic
Chemistry, USTHB, BP 32, 16111 Algiers, Algeria
e-mail:[email protected]
I. Sebai
Faculty of Chemistry, USTHB, LCGN, BP 32, Algiers 16111, Algeria
M. Trari
Laboratory of Storage and Valorisation of Renewable Energies, Faculty of Chemistry, (USTHB),
BP 32, 16111 Algiers, Algeria
© The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer
Nature Singapore Pte Ltd. 2021
A. Khellaf (ed.),Advances in Renewable Hydrogen and Other Sustainable Energy
Carriers, Springer Proceedings in Energy,
https://doi.org/10.1007/978-981-15-6595-3_4
25

26 R. Bagtache et al.
regard, the photo-catalysis has attracted much attention for the degradation of organic
pollutants into small molecules and/or total mineralization [2]. In recent years, the
photo-catalysis has become a challenge to face the modern world as it provides an
alternative simple using a source of energy (artiﬁcial: lamp or natural: sunlight) to
achieve the chemical transformation [3]. Currently, compounds with a spinel structure
AB
2O4such as ZnCo2O4,NiCo2O4,CuAl2O4,CuCr2O4,ZnCr2O4,MnCo2O4and
CuCo
2O4received special attention because of their numerous applications in many
ﬁelds such as: electronics, magnetism, catalysis, electro-catalysis, photo-catalysis,
etc.
As examples these oxides, CuCo
2O4is a promising oxide in the ﬁeld of storage
energy; this is due to its properties: high chemical stability, electrochemical stability,
ecofriendly, low cost, refractor, super-capacitor, moisture sensor and negative elec-
trode in Li-ion battery materials [4–8]. We report our contribution by synthesizing for
the ﬁrst time CuCo
2O4, by co-precipitation at low temperature from sulfates reagents
and the physical and photoelectrochemical characterizations are reported. Moreover,
we successfully tested the as-prepared material in the hydrogen production.
4.2 Experimental
The co-precipitation was used to prepare CuCo2O4in presence of sulphate by mixture
of 3.2394 g of CoSO
4and 5.0872 g of CuSO4;5H2O (Merck 99%) in 250 mL of
distilled water; the pH was adjusted with KOH at 12.25. Then, product is treated in
air oven at 140 °C for 3 days. The recovered product was ﬁltered, washed and dried
overnight at 60 °C.
The X-ray diffraction (XRD) pattern was recorded with a Panalytical with Cu Kα
anticathode (λ=0.154128 nm) in the range [2θ: 5–90°] to identify the synthesized
phase. The optical absorption spectrum of CuCo
2O4was performed with a Jasco 650
UV–Vis spectrophotometer, BaSO
4was used as reference.
The photo-electrochemical properties were studied in a standard cell with Pt
auxiliary electrode; all potentials were reported against a saturated calomel electrode
(SCE); the latter was separated from the working solution by a fritted bridge ﬁlled
with the same solution and the potential was uncorrected for the junction potential.
The electrode potential was piloted by a computer aided Versa STAT3 potentiostat
and the interfacial capacitance was measured at 10 kHz.
The photocatalytic experiments were carried out in a Pyrex reactor (200 mL
capacity) connected to a thermo-stated bath (50 °C); no temperature increase of
the solution was observed during irradiation. 100 mg of CuCo
2O4are suspended in
200 mL of aqueous solution (Na
2SO3or Na2S2O3,10
−3
M) under magnetic agitation
(210 rpm); the pH is adjusted by NaOH (pH ~ 12).

4 Preparation of the Spinel CuCo2O4at Low Temperature … 27
4.3 Results and Discussion
The powder XRD pattern of CuCo2O4(Fig.4.1a) shows the peaks observed at
2θ~ 19°, 31.1°, 36°, 38°, 45°, 59°, 65° are typical of spinel cubic structure with
space group of F d3 m and the result perfectly agree with the standard values of the
JCPDS N° 00-001-1155. No other impurity peaks were observed, which indicates
that high purity of CuCo
2O4. The crystallite size of CuCo2O4(D=32 nm) is calcu-
lated from the full width at half maximum (FWHM,β=0.26°) of the strongest XRD
peak (311):
D=0.9λ(βcosθ) (4.1)
To probe the optical properties, we have determined the forbidden band (E
g)of
CuCo
2O4, by using the Pankov formula:
(αhν)
2/m
=Const×(hν−E g+Eph) (4.2)
whereα(cm
−1
) is the optical absorption coefﬁcient and hν(eV) the energy of incident
photon; the exponent m=4 and 0.5 respectively for direct or indirect transitions;
E
phis the phonon energy for indirect transitions when the bottom of CB (Conduction
Band) does not coincide with the top of VB (Valence Band).
The extrapolation of the straight line (αhv)
2
to the abscissa axis (hν=0) provides
a direct transition at 1.38 eV (Fig.4.1b), due to the degeneracy lift of d-orbital of
Co
3+
in octahedral site into an upper t2glevel and higher eglevel obeying the selection
rules. The existence of the gap is in conformity with a semiconducting behavior. The
other important factor in photo-catalysis is the semi conductivity which produces a
space charge region near the interface where most if not all pairs the electron/hole
(e
−
/h
+
) are separated.
The electrical conductivity (σ) against 1000/T, determined on sintered disc, obeys
to the lawσ=σ
oexp {Ea/RT} with a room temperature value (σ 300 K)of10
−4
(λ
Fig. 4.1 aX-ray diffraction pattern andbdirect optical transition of CuCo 2O4prepared by co-
precipitation route from sulfate precursors

28 R. Bagtache et al.
1,6 2,0 2,4 2,8 3,2
-4,0
-3,5
-3,0
-2,5
-2,0
-1,5
-1,0
-0,5
Log sigma cm)
-1
1000/T (K
-1
)
(a)
Ω
Fig. 4.2 aThe logarithm of the electrical conductivity (σ) versus reciprocal absolute temperature
andbprojection of structure of CuCo2O4
cm)
−1
(Fig.4.2a). The activation energy of 0.38 eV, deduced from the slope d logσ/dT
(Fig.4.2a) conﬁrms the semi conductivity and where the acceptors are no longer
ionized. The holes move in a narrow with deriving from Co
3+
: 3d a mobility of 2.5×
10
−6
cm
2
V
−1
s
−1
, obtained from the conductivity of CuCo2O4(σ=eμhNA). Such
low mobility comes from to the obstruction of O
2−
ions to the electron’s movement
across octahedra/tetrahedra sharing respectively common edges/corners in the spinel
structure (Fig.4.2b). The conduction mechanism is governed by low polaron jump
with phonon assisted conduction through mixed valences Co
3+
/
2+
.
The intensity-potential J(E) proﬁle in the dark is asymmetrical, indicating an
irreversible and sluggish system (Fig.4.3a); the peaks at ~−0.28 V along the negative
potential, correspond to the irreversible reduction of dissolved oxygen (O2+2H2O
+2e
−
→H2O2+2OH
−
) to peroxide H2O2, such potential is close to that cited in
the literature (−0.38 V).
The drastic decrease of the dark current Jdbelow−0.6 V is due to H2evolution.
On the other, the augmentation beyond 1 V is due to oxygen liberation (H2O+2h
+
-1,0 -0,5 0,0 0,5 1,0
-0,004
-0,002
0,000
0,002
Current density (A cm
2
)
Potential (V)
Dark
----- Under illumination
(a)
-0,9 -0,6 -0,3 0,0 0,3 0,6
0,0
0,3
0,6
0,9
1,2
C
-2
10
10
(F
-2
cm
4
)
Potential (V)
V
fb
= 0.28 V
(b)
Fig. 4.3 aThe current J versus (E) characteristic andbthe Mott-Schottky of CuCo2O4at pH ~ 12

4 Preparation of the Spinel CuCo2O4at Low Temperature … 29
0 2 4 6 8 10121416
0
20
40
60
80
100
120
NaOH ( pH12 )
Na
2
SO
4
( pH7 )
V
H
2
(
μ
mol)
Time (min)
(a)
0246810121416
0
30
60
90
120
150
180
NaOH/Na
2
SO
3 NaOH/Na
2
S
2
O
3
NaOH
V
H
2
(
μ
mol)
Time (min)
(b)
~
~
Fig. 4.4 aVolume of evolved oxygen versus illumination time at different pH ~ 7 and 12 andbby
various electrons scavengers S2O3
2−
and SO3
2−
of CuCo2O4
→0.5O2+2H
+
) and this clearly indicates that the photo holes do not oxidize water
because of the narrow band gap Egof the spinel CuCo2O4(1.38 eV).
The ﬂat band potential (Efb) and the carriers density (NA/D) is obtained
by measuring the capacitance (C) versus applied potential (E) at the interface
CuCo2O4/NaOH:
C
−2
=±(0.5×eεεoNA)
−1
{E−Efb} (4.3)
The sign±correspond respectively top-orn-type behavior, e the electric charge,
εandεothe permittivity of material and vacuum respectively.
The negative slope is characteristic of p-type semi-conductivity; the potential Efb
(0.28 V) and the holes density NA(8.7×1018 cm
−3
) are simply deduced from
the intercept with the abscissa axis and the slope of the straight line (C
−2
−E)
respectively (Fig.4.3b).
The Efbvalue comes from the small ionization energy of3dmetal and provides
the position of the conduction band (−0.72 V=Efb+Ea/e−Eg/e)
1
, such value is
more cathodic than the potential of the H2evolution (~−0.8 V), the latter was simply
deduced from the J(E) proﬁle. Accordingly, the potential valence band is equal to
0.66 V (=ECB+Eg). The holes can react with sulﬁte SO3
2−
through a valence band
process; such reaction favors the charges separation and improves the photo-activity.
The spinel alone gives an appreciable H2volume because of the difference between
CB (−072 V) and H2level which moderate the electrons transfer, (Fig.4.4a) is
found with an evolution rate of 340μmol min
−1
(g catalyst)
−1
. The pH inﬂuences
the photocatalysis; indeed, the bands of CuCo2O4formed from3dorbital are pH-
independent while that of the H2O/H2follows the nerstian variation of 0.06 V/pH.
This property has been judiciously exploited to get an optimal band bending at the
junction CuCo2O4/electrolyte equal to the difference {EH2O/H2
−ECB}. The lower
1
The activation energies of CuCo2O4(0.38 eV) was measured from the electrical conductivity on
sintered pellets.

30 R. Bagtache et al.
the over potential, the rougher the active area and the co-precipitation yield a porous
structure with an improved surface area. The crystallite size (32 nm) should give
a minimal surface area of 37 m
2
g
−2
{=6(ρD)
−1
},ρis the experimental density
(5.05 g cm
−3
). The photo-voltage for the H2O splitting is smaller than the theoretical
value (θG°
R/nF=1.23 V) of the total reaction and the splitting cannot occur because
of O
2and H2over-voltage. The H2evolution occurs concomitantly with the SO3
2
−
oxidation; SO3
2
−
was selected in the goal to contribute to the charges separation and
to improve the photo-activity (Fig.4.4b). The H
2liberation requires 2 photons by
H
2O molecule and the quantum efﬁciency (η) is given by:
η=2×V×N/(β×V
m×t) (4.4)
V and V
mare respectively the volume of evolved H2formed and the molar volume,
N the Avogadro number andβthe photons ﬂux absorbed by CuCo
2O4.
A light ﬂux of 2.09×10
19
photons s
−1
was measured, leading toηvalue of 1.1%.
Initially, the hydrogen production occurs with a high evolution rate and slows down
over time; the saturation is observed beyond 14 min; indicating the occupation of
photoelectrochemical sites by H
2molecules.
4.4 Conclusion
The spinel CuCo2O4was prepared by co-precipitation in KOH medium at low
temperature, not exceeding 140 °C using sulfates of copper and cobalt as precursors.
The compound crystallizes in a cubic system with a lattice constant of 8.0590 Å. The
X-ray diffraction (XRD) pattern conﬁrms the single phase and the diffuse reﬂectance
of the black product indicated a direct transition of 1.38 eV coming from the crystal
ﬁeld splitting. CuCo
2O4was characterized photo-electrochemically; the measure-
ment done in alkaline electrolyte showed an electrochemical stability with a cathodic
peak assigned to the oxygen reduction to peroxide. The capacitance-potential indi-
cated p-type semi-conductivity. The spinel was successfully tested for the hydrogen
formation under visible light illumination using SO
3
2
−
as sacriﬁcial agent; a quantum
yield of 1.1% was obtained.
References
1. R. Bagtache, K. Abdmeziem, K. Dib, M. Trari, Synthesis and photoelectrochemical characteri-
zation of KZn 2 (HPO 4) PO 4: application to rhodamine B photodegradation under solar light.
Int. J. Environ. Sci. Technol.16(7), 3819–3828 (2019)
2. R. Bagtache, K. Abdmeziem, G. Rekhila, M. Trari, Synthesis and semiconducting properties of
Na2MnPO4F. Application to degradation of Rhodamine B under UV-light. Mater. Sci. Semicond.
Process.51, 1–7 (2016)

4 Preparation of the Spinel CuCo2O4at Low Temperature … 31
3. C. Belabed, B. Bellal, A. Tab, K. Dib, M. Trari, Optical and dielectric properties for the determi-
nation of gap states of the polymer semiconductor: application to photodegradation of organic
pollutants. Optik160, 218–226 (2018)
4. M.H. Habibi, Z. Rezvani, Photocatalytic degradation of an azo textile dye (CI Reactive Red
195 (3BF)) in aqueous solution over copper cobaltite nanocomposite coated on glass by Doctor
Blade method. Spectrochim. Acta Part A Mol. Biomol. Spectrosc.147, 173–177 (2015)
5. M.J. Iqbal, B. Ismail, C. Rentenberger, H. Ipser, Modiﬁcation of the physical properties of
semiconducting MgAl2O4 by doping with a binary mixture of Co and Zn ions. Mater. Res. Bull.
46(12), 2271–2277 (2011)
6. R. Rahmatolahzadeh, M. Mousavi-Kamazani, S.A. Shobeiri, Facile co-precipitation-calcination
synthesis of CuCo
2O4nanostructures using novel precursors for degradation of azo dyes. J.
Inorg. Organomet. Polym Mater.27(1), 313–322 (2017)
7. S. Sun, Z. Wen, J. Jin, Y. Cui, Y. Lu, Synthesis of ordered mesoporous CuCo
2O4with different
textures as anode material for lithium ion battery. Microporous Mesoporous Mater.169, 242–247
(2013)
8. S. Vijayakumar, S.-H. Lee, K.-S. Ryu, Hierarchical CuCo
2O4nanobelts as a supercapacitor
electrode with high areal and speciﬁc capacitance. Electrochim. Acta182, 979–986 (2015)

Chapter 5
Synthesis and Electrochemical
Characterization of Fe-Doped NiAl
2O4
Oxides
Warda Tibermacine and Mahmoud Omari
AbstractA new spinel solid solution system of Ni
1−xFexAl2O4(0.0≤x≤0.5)
was synthesized through sol-gel method. The effect of Fe doping on the electro-
catalytic properties of nickel aluminate was investigated. The synthesized powders
were characterized by means of X-ray diffraction, scanning electron microscopy and
electrochemical measurements. From the preceding analysis, it can be shown that
compounds show a single spinel phase in the temperature range of 650–1000 °C and
the solubility of iron in the NiAl
2O4structure was limited to x≤0.5. The electro-
chemical measurements indicate that the catalytic activity is strongly inﬂuenced by
iron doping. The highest electrode performance is achieved with Ni
0.7Fe0.3Al2O4(i
=86.84 mA/cm
2
) which is ~27 times greater than that of NiAl2O4(i=3.22 mA/cm
2
)
at E=+0.8 V. After one hundred cycles, the stability of the doped electrode with
30% of iron is much better than that of the undoped electrode. These results indi-
cate clearly that Ni
0.7Fe0.3Al2O4electrode has promising potential for cost-effective
potential generation.
KeywordsSpinel oxide
·Sol-gel·Oxygen evolution reaction
5.1 Introduction
Nanocrystalline metal aluminates possess important applications in various ﬁelds
such as heterogeneous catalysis, pigments, sensors and ceramics [1–6]. Aluminate
spinels have been used as catalysts in the decomposition of methane, steam reforming
dehydration of saturated alcohols to oleﬁns, dehydrogenation of alcohols, etc. These
oxides have also been reported as good photocatalysts, e.g. for the degradation of
methyl orange [7–9].
Nickel aluminate has been used in various catalytic applications and high temper-
ature fuel cells, due to its high melting point, high activity and resistance to corrosion
W. Tibermacine (B)·M. Omari
Laboratory of Molecular Chemistry and Environment, University of Biskra, 07000 Biskra, Algeria
e-mail:[email protected]
© The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer
Nature Singapore Pte Ltd. 2021
A. Khellaf (ed.),Advances in Renewable Hydrogen and Other Sustainable Energy
Carriers, Springer Proceedings in Energy,
https://doi.org/10.1007/978-981-15-6595-3_5
33

34 W. Tibermacine and M. Omari
[10]. It has been proposed as a promising candidate for an anode in aluminum produc-
tion and as an anode in an internal reforming solid oxide fuel cell (IR-SOFC) [11],
in addition it has been used as good electrocatalysts for the oxidation of organic
compounds and nitrous oxide [10], and also as inert anodes in aluminum electrolysis
[12]. On the other hand, the spinel NiAl
2O4is photosensitive to visible light [13],
and it presents an attractive property in photocatalysis [14].
This oxide can be properly modiﬁed by the partial substitution of atoms at A
and/ or B sites which may affect strongly its physical property. Nickel aluminate
(NiAl
2O4) oxide doped on the A site with various metal ions such as Cu [15], Cd
[16], Mg [17], Ce [18], were previously studied. A few years ago, it has been reported
that the oxygen evolution reaction (OER) indicates that substitution of Ni by Fe in
Ni
0.9Fe0.1Co2O4spinel increases the electrocatalytic activity of the resulting material
signiﬁcantly [19]. On the other hand, another work on mixed Fe-Ni oxide catalyst
showed much higher activity toward oxygen evolution and methanol oxidation than
either of the pure oxides with a peak in activity occurring near 10 mol% Fe [20]. In
alkaline solution some substituted ferrites which the foreign element was added to
the B site such as CoFe
1.7Ni0.3O4, CoFe1.6Mn0.4O4[21] and NiFe2-xCrxO4(0≤x≤
1) [22], manifest a reduced oxygen over-potential. Despite all these precedent works
on spinel oxides based on iron and nickel, there is no report on the solid solution and
activity of Ni
1-xFexAl2O4materials for the oxygen evolution reaction.
In the present study, we examine the effect of partial substitution of nickel by iron
on structural, grain morphology, surface area, electrocatalytic activity and stability
of Ni
1-xFexAl2O4(0≤x≤0.5) electrodes prepared by the sol-gel method.
5.2 Experimental Procedure
Different nickel aluminate powders were prepared according to the formula
Ni
1−xFexAl2O4(0≤x≤0.6) by a sol-gel process. Fe(NO3)3∙9H2O (BIOCHEM),
Ni(NO
3)2∙6H2O (BIOCHEM), Al(NO3)3∙9H2O (FLUKA) and citric acid (JANSSEN
CHIMICA) were used as salt precursors. The calculated amount of Fe(NO
3)3∙9H2O,
Ni(NO
3)2∙6H2O, Al(NO3)3∙9H2O was dissolved in C2H5OH 99%. Then, the proper
amount of citric acid dissolved in ethanol was added where the mole ratio of total
metal ions and citric acid is 1:2:3. The resulting solution was slowly stirred, heated
and concentrated by evaporating the ethanol at 80 °C until a gel was obtained. This
last was then dried in an oven slowly upon increasing the temperature to 110 °C for
12 h in order to produce a solid amorphous citrate precursor. The resulting precursor
was calcined in air for 6 h in the temperature range 400–1000 °C with a heating rate
of 5 °C min
−1
.
X-ray diffraction (XRD) was performed with a D8 Advance Brucker using a
Cu K
αline at 0.1540 nm in 2ºrange of 10°–90° in steps of 0.010°. Linear sweep
and cyclic voltammetry experiments for O
2evolution were performed in potassium
hydroxide 1 M using a Parstat 4000 potentiostat-galvanostat with oxide powders, Pt
plate and Hg/HgO as working, auxiliary and reference electrodes, respectively.

5 Synthesis and Electrochemical Characterization of Fe-Doped … 35
Fig. 5.1XRD patterns of
the Ni
1−xFexAl2O4(0≤x≤
0.6) samples calcined at
(650–1000 °C) (s): spinel;
(*): FeAl
2O4
5.3 Results and Discussion
5.3.1 XRD Study
The XRD patterns of the Ni1−xFexAl2O4(x=0, 0.1, 0.2, 0.3, 0.4, 0.5 and 0.6)
calcined at 650–1000 °C for 6 h in air are shown in Fig.5.1. The results conﬁrm
that all samples with 0≤x≤0.5 are consistent with the standard data for NiAl
2O4
spinel phase (JCPDS card No. 10-0339), indicating the formation of a single phase
with space group Fd3m and with no detectable secondary phase. These peaks can
be indexed as (111), (220), (311), (400), (422), (511) and (440) planes, respectively.
These planes are associated with the nickel aluminate spinel with a cubic structure.
For x=0.6, the main phase was also cubic spinel with another phase FeAl
2O4(JCPDS
card 00-007-0068) indicating a Fe solubility limit of ~0.5 in the Ni
1−xFexAl2O4.
5.3.2 SEM Analysis
The crystallite size (Dhkl) of the samples 0≤x≤0.5 was calculated using Scherrer’s
equation (Eq.1)[23].
D=kλ/βcosθ (1)
where D is the average size of crystallites (nm), k Scherrer constant (≈0.9),λwave-
length of the incident radiation (nm),θhalf of the angular position of the peak
concerned andβfull width at half maximum. The crystallite size was calculated
for different samples in the range of 13.4–43 nm indicating that the spinel powders
prepared by sol-gel method are composed of nanometric particles. The crystallite

36 W. Tibermacine and M. Omari
Fig. 5.2SEM micrographs of Ni 1−xFexAl2O4.ax=0.2;bx=0.3 calcined at 800 °C
size decreases with increasing iron content. A similar result was also found for
Ni
0.9Fe0.1Co2O4[19]. This is probably due to the incorporation of iron into the
NiAl
2O4lattice, which leads to the formation of either cation or oxygen vacancies
reducing the crystallite size.
The SEM micrographs of Ni
1−xFexAl2O4samples are shown in Fig.5.2a,b. Parti-
cles have different shapes, sizes and the powders are agglomerated. The particle size
is appreciated between 0.6 and 2.3μm. The formation of agglomerate is probably
due to the nature of the solvent used in the preparation of samples [24].
5.3.3 Electrochemical Properties
Polarization studies under potentiostatic conditions for Ni1−xFexAl2O4(0≤x≤0.5)
catalysts were carried out (Fig.5.3). The highest electrode performance is achieved,
for anodic current density with Ni
0.7Fe0.3Al2O4. Oxygen evolution reaction shows
an important jump for (0.0≤x≤0.3), where the current density of Ni
0.7Fe0.3Al2O4
(i=86.84 mA/cm
2
) is ~27 times greater than that of NiAl2O4(i=3.22 mA/cm
2
)
at E=+0.8 V. As Fe content is increased beyond 30%, catalytic activity starts to
decrease. The improvement of catalytic activity with incorporation of iron (x≤0.3)
is probably due to the amelioration of the conductivity and the crystallinity of the
doped material [25]. Burke et al. have also reported the role of iron in activating OER
catalysts [26]. It has been shown that oxidized nickel (oxy) hydroxide is conductive
and thus electrically connects the dispersed Fe sites to the conductive electrode. On
the other hand, the electronic interaction between Ni and Fe likely further activates
the Fe site for the OER. For higher iron content (x > 0.3), the trend reverses and
the catalytic activity becomes lower. This can be probably due to that these catalysts
have not the optimal M–O bond strength that is, this bond which constitutes an

5 Synthesis and Electrochemical Characterization of Fe-Doped … 37
Fig. 5.3I–E polarization
curves of oxygen evolution
reactions of Ni
1−xFexAl2O4
electrodes in 1 M KOH
intermediate specie of the OER mechanism is too strong or too weak. On the other
side, Friebel et al. [27] have reported that for Fe content of 25–50%, the presence of
the phase-segregated FeOOH that lowered the overall geometric activity. This is due
to that FeOOH is electrically insulating and thus OER is less active [26].
The chemical stability of Ni
1−xFexAl2O4oxides under oxygen evolution reaction
conditions was tested. Figure5.4shows the cyclic voltammograms of the 1
st
and
100
th
cycle for NiAl2O4and Ni0.7Fe0.3Al2O4electrodes towards oxygen evolution
reaction. In the two cases, after one hundred cycles, the curves show almost similar
peaks with a slight decrease in current density for the undoped sample while it
becomes higher for Ni
0.7Fe0.3Al2O4at E > 0.7 V.
Indeed, during 100 cycles, the current density decreases from 3.22 to
2.11 mA/cm
2
(~34%) for NiFeAl2O4and increases from 86.84 to 91.75 mA/cm
2
for Ni0.7Fe0.3Al2O4(~5.65%) at E=0.8 V. This result indicates clearly that the
stability of the electrode doped with 30% of iron is much better than the undoped
Fig. 5.4Cyclic
voltammograms of NiAl
2O4
and Ni0.7Fe0.3Al2O4for the
1st and 100th cycles in 1 M
KOH media

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CHAPTER XVII
DOWN THE COAST OF PERU—LAKE TITICACA
AND LA PAZ—THROUGH THE ANCIENT INCAN
EMPIRE TO COCHABAMBA
The coast of Peru looked decidedly uninviting as day after day
the S. S. Palena of the Chilean Line nosed her way southward
through the placid water of the Pacific. The high, rocky shore
stretched on interminably, it seemed; no graceful palm or speck of
green of any kind gladdened the eye; there were only the barren
cliffs, against which the swell dashed itself into snowy spray and,
above them, slopes of hot brown sand.
This was in sharp contrast with the low Ecuadorian shore-line;
that was bad enough, with its dense, dark jungles growing to the
water’s very edge, its overhanging masses of black clouds, and its
breathless heat and silence that seemed to exude all the fatal
maladies of a tropical clime. Nevertheless, there was a suggestion of
life of some sort—inhospitable though it might be. It was not as if an
outraged divinity had seared the land with withering breaths of hate,
annihilating everything that possessed or gave promise of life, and
leaving only the scorched desert as a fearsome reminder of celestial
vengeance. But if the land appeared forsaken, the ocean teemed
with life. Flocks of gulls always remained in the vicinity of the ship,
and occasionally we saw petrels, shearwaters, and albatrosses;
whales were not particularly plentiful, but porpoises appeared

practically every day. Toward the end of the voyage seals also grew
abundant.
There are numbers of ports along the Peruvian coast and the
Palena stopped at many of them. The enormous swell coming from
the south and scarcely felt at sea spends its violence along the
shore, making landing very difficult, and often impossible.
Steamships dare not approach close to the jutting rocks. All freight is
unloaded into lighters; passengers are lowered in a chair operated
by a steam-winch and dumped into the huge, flat-bottomed freight-
carriers, together with their belongings. This always causes a good
deal of excitement and not infrequently slight injuries are inflicted,
as the boats are low one instant and come racing up the next on the
top of a mountainous swell.
At noon on the eighth day out from Panama we reached Paita.
The town lies on the beach and just below the edge of a high sandy
plateau. This is the centre of Peru’s oil-fields. Tanks were visible in
the country near the town, and a thin film covered the water for
several miles off-shore.
Salavery is a small town with flat, square board houses. In back
of it rise high escarpments of rock and sand. It never rains, so water
is brought from a little valley far distant in the foot-hills. A narrow-
gauge railroad connects the valley with the port, and sugar is
brought out for export.
It seems as if most of the coastal towns are merely ports or
outlets for products from the interior. There are many fertile little
spots between the ridges branching off from the main range; they
are well watered by melting snow on the lofty summits, and a great
variety of fruit, vegetables, cotton, and cane are grown.
After ten days the ship anchored off Callao; it is but a thirty
minutes’ train ride from this port to Lima. The route is flat and runs
through corn, banana, and yucca fields and truck-gardens. We
visited the creditable zoo and then accepted an invitation to inspect
the medical college. The latter is surprisingly well equipped and had

an attendance of over eight hundred students. The great cathedral
next occupied our attention; the massive temple was in itself most
interesting, but curiosity led me to spend the most of our limited
time viewing the remains of Pizarro, which are exhibited in a glass-
panelled marble casket. An inscription informs the viewers that the
conquistador founded Lima in 1535; he died June 26, 1541, and was
buried under the cathedral; in 1891 the bones were exhumed and
placed in their present resting-place. If one may believe the
statements of historians, a monument built of the skeletons of his
helpless victims would be a far more suitable memorial to the
bloodthirsty outlaw than the place of worship which his remains of
necessity must defile.
We had heard a great deal about the difficulty of landing at
Mollendo. At times the rollers from the south are so immense that
ships do not attempt an anchorage, but continue the voyage down
to Arica. We were relieved to find the sea perfectly smooth upon our
arrival. The town differed from Paita and Salavery only in that it was
somewhat larger. We found it possible to purchase through tickets to
La Paz, and noon saw us on our way. The railroad started up the
barren slope almost immediately; occasionally the incline was very
gentle—so gentle, in fact, that the country lay like a great brown
desert on each side of the track. These stretches were covered with
crescent-shaped sand-dunes, some of them fifty feet high and
several hundred feet from tip to tip. They creep slowly forward as
the wind blows the sand up their rear slope to the crest, when it
topples over into the centre of the half-moon.
At times the grade was very steep. The deep blue Pacific was
visible several hours, sometimes on our right and then on our left, as
the train wound up the mountainside, but always receding until it
resembled a vast mist-enshrouded amethyst losing itself in the
distance.
Alkali-dust entered the coaches in clouds and threatened to
suffocate the passengers, but the impressiveness of the scenery
more than compensated them for this annoyance.

Not far from Arequipa a deep gorge appeared with a stream
threading its way through the bottom. Its banks were covered with
trees and green vegetation—a veritable oasis amid the desert that
hemmed it in on both sides. The Indians who now came to the car-
windows when the train stopped to get up steam brought grapes,
figs, oranges, guavas, and empanadas, or meat pies smelling
strongly of onions. They were an unkempt, wild-looking lot and had
apparently come from the green vale below. At seven o’clock we
were up seven thousand feet, having ascended to that height from
sea-level in six hours, and drew in at the station of Arequipa.
There was no train for Puno the following day, so ample time
was at our disposal in which to see the city and its immediate
environs.
We found Arequipa to be a most delightful place. It was cool
enough to permit the wearing of top-coats with comfort. The people
were well dressed and healthy appearing. Electric trains provided
adequate means of journeying from one part of the city to another,
and if one preferred a carriage it also was obtainable. Beautiful
plazas, ancient churches, and wooden buildings are distributed
promiscuously among the rabble of low adobe or stone huts which
predominate, and herds of llamas thread their way through the
stone-paved streets. The atmosphere is so clear the year around
that a spot near the city has been chosen for the site of the Harvard
Observatory. One has a good view of the great snow-capped Mount
Misti from every part of the city; the peak is conical in shape and
nineteen thousand two hundred and fifty feet in height.
Continuing the trip from Arequipa, the first stage of the route
passes over barren, gently rolling country. Small irrigated plots are
not uncommon where some rivulet trickles down from the upper
world of snow and ice; they support a limited population of Indians,
which must lead a forlorn and miserable life among their desolate
surroundings. Farther on, the slopes assumed a friendlier
appearance; sparse vegetation in patches appeared and grew denser
toward the snow-line, where there was naturally more moisture. Life

followed closely in the wake of the grass and bush covered areas.
Native hovels became more numerous, and flocks of llamas, sheep,
and goats, with a sprinkling of horses and cattle, fed on the
herbage.
Country around Arequipa, showing Mount Misti.
The expedition en route via hand-car, Changollo to Arce.

The top of the divide is fourteen thousand five hundred feet
above sea-level. As we approached it numbers of passengers
became violently ill of soroche, or mountain-sickness. They acted
very much like people aboard a steamship on a stormy voyage,
although this illness seemed far worse than any seasickness I had
ever seen. Several of the stricken ones rolled about on the floor and
tried to tear off their clothing; a feeling of suffocation accompanies
the nausea, and occasionally some one dies.
Beyond the ridge the country is level or gently rolling and there
are numerous clear blue lakes—some of considerable size. Immense
flocks of doves make this upland region their home, and ducks,
gulls, and herons teemed about the water.
Just after dark we reached Puno, and a few minutes later
embarked on the Coya for the trip across Lake Titicaca. The night
was so cold and stormy that it was impossible to spend much time
on the upper deck, and the cabins were so crowded that sleeping in
comfort was impossible. The ship was small and overcrowded with
people of many colors and nationalities; most of them spent the
night in the dining-saloon drinking and gaming.
Dawn came at last, and shortly afterward the Coya slowly
wended her way through the reed-grown marshes bordering the lake
and tied up at the pier at Guaqui, on the Bolivian side. Indians in
reed rafts with sails made of rushes dashed past and disappeared
among the cattails, and water-fowl of several species—mostly ducks,
coots, and grebes—paddled out into the ruffled water left in the
wake of the boat.
It is unfortunate that this passage of the lake is made at night.
Nearly every one visiting the vast body of water for the first time is
eager to see as much of it as possible, both on account of its being
the highest great lake in the world (twelve thousand five hundred
feet above sea-level) and by reason of its associations with the
nation of the Incas.

Guaqui is a garrison town. There were numerous soldiers in
evidence on the streets, and a troop of lancers, under the command
of a German officer, were giving a skilful display of their prowess on
the lake front. Their mounts were not much to look at and the
uniforms of the men were rather shabby, but both were well drilled.
The train for La Paz left at noon. It moved at a good rate of
speed across the high, level upland. The scenery is impressive. We
were always in sight of snow-covered peaks, although there was
little snow on the plateau itself. Indian huts built of stone, some very
ancient, are scattered about abundantly, but it requires some
experience in locating them before they can be readily distinguished
from their immediate surroundings. There were numerous fields of
wheat and oats, and llamas without number nibbled the scant
vegetation on the slope. In a few isolated spots small herds of cattle,
horses, and pigs were visible. Indians came to the coach-windows to
sell fruits when the train stopped; they were doubtless brought from
the deep, sheltered fissures that have been cut into the range by
snow-water from high peaks.
Within a short time we had reached the ruins of an enormous
city called Tiahuanaco, which is said to date back many centuries
before the Incan era. When discovered it was buried in the sand
level with the surface of the plateau, but archæologists have
excavated many of the larger buildings and brought to light ancient
treasures of rare beauty. Later, in La Paz, we met a man named
Poznaski who had done a great deal of work in this region. He had a
remarkable collection of hundreds of skulls, pieces of pottery, gold
ornaments, and well-preserved cloth. Among the ceramics was a
“death’s head” of exquisite workmanship, life size, and painted in
gorgeous colors. He considered it the finest bit of pottery ever
discovered in Bolivia and stated that a North American museum was
negotiating for its purchase at a price that ran into five figures. This,
however, did not seem probable. As we neared La Paz, the great
mountains of Illimani, Murarata, and Huana Potosi loomed constantly
more lofty and forbidding before us. They are the patriarchs of the
Bolivian Andes, and are twenty-two thousand five hundred and

eighty-one, twenty-one thousand, and twenty thousand two hundred
and eighty-nine feet high respectively. The summits of all three have
been reached by venturesome exploration-parties, but the task of
climbing the steep, slippery slopes perpetually covered with deep
snow and swept by frigid gales is a trying one that is not often
attempted. Huana Potosi, the more distant of the group has a flat
top, contrasting conspicuously with the sharp, pointed summits of
the other two. The Indians tell a legend that explains this peculiar
formation. In the days of long ago, when the world was young,
vapors enveloped all the earth; suddenly the sun-god appeared and,
beaming down from heaven, caused the mists to become dissipated
and vanish. Illimani awoke to life and from his dizzy height beheld
the queenly Huana Potosi smiling up at him. At the same time,
however, Murarata emerged from the clouds and beholding the
beautiful Huana Potosi fell violently in love with her. Illimani became
insanely jealous and in a blind fury hurled forth fire, smoke, and
stones of great size at his rival’s head; the latter promptly replied in
kind and fought valiantly. For days the earth quaked and trembled
with the thunderous roar of the death-struggle, while heavy clouds
covered the terrifying spectacle with a mantle of darkness. After a
seemingly endless time the combat stopped; daylight returned,
revealing an appalling state of affairs. Finding it impossible to
vanquish the rival suitor, Illimani had beheaded his fair lady-love to
prevent her from falling into the other’s hands. The many streams of
water rushing down the steep sides of Illimani are but the tears of
grief and remorse over his hasty action; thus he is doomed to mourn
and weep until the end of time. The legend has doubtless been
handed down through many generations and obviously refers to one
of the many volcanic disturbances that must have occurred when the
Andes were young.
Shortly before sundown we came suddenly to the brink of a
crater-like rent in the plateau and, on the bottom of the huge gash,
thirteen hundred feet below, we could see the compactly built mass
of edifices and green gardens of La Paz. The situation of the city is
unique. One has no intimation of its nearness while speeding over

the high, cold plano alto (which has an elevation of thirteen
thousand three hundred feet) until the very edge of the fissure is
reached. The sides are precipitous, but numerous footpaths make
their way up or down the steep declivity. The far slopes of the Andes
are checkered with cultivated fields; a roaring stream, the
Choqueyapu, tears its way through the floor of the amphitheatre,
and the series of snow-covered summits form a magnificent
background for the unusual spectacle.
The steam-locomotive was taken off and an electric one
substituted, and then the train slowly backed down along the face of
the incline to the station below.
The impression of La Paz, gained from the first brief view above,
is soon dispersed upon nearer and more intimate acquaintance. The
streets are narrow, crooked, paved with small stones from the river-
bed, and very steep. Walking any length of time entails a great
amount of exertion on account of the high altitude; fortunately,
carriages are not lacking, and a tramway also provides a ready
means of locomotion, or I am afraid few travellers would ever see
very much of the inner life of the city. With the exception of a few
churches and government buildings that are worthy of note on
account of their size and architecture, the buildings are low and of a
primitive type, whitewashed and covered with tiles or thatched.
Ordinarily the streets are all but deserted, but on Sundays and
fête-days a motley crowd throngs the winding thoroughfares. There
are full-blooded Indians of the Aymará race, clothed in picturesque
though not beautiful garments; half-breeds or Cholos are far more
gayly clad in very full skirts and shawls of bright colors, round, flat-
brimmed straw or felt hats, and imported shoes with high heels and
tops that reach almost to the knees; the number of townspeople,
creoles and foreigners, seems negligible compared to the throngs of
Indians and Cholos; in fact, some authorities state that there are
one hundred of the latter to one of the former. On market-days long
lines of llamas, burros, and mules thread their way through the

crowded streets, bearing fire-wood, charcoal, meat, and vegetables
for the sustenance of the city.
About the most interesting place in La Paz to us, and at the
same time the most repellent, was the Museo Nacional. It contained
several dark, cavernous rooms crowded with a wealth of specimens,
mostly in the form of ceramics, minerals, and mummies. They were
piled promiscuously everywhere in the most slovenly and disgusting
manner. Naturally, this treatment did not tend toward their
preservation; rats had undermined the mounds of human remains,
gnawed holes into the bodies, and made their nests in the interior;
pottery had crashed from unstable shelves, and bird and mammal
skins were badly moth-eaten. I trust that a more efficient
management may rescue these treasures.
The plazas, of which there are four or five, are small and not
particularly attractive. The cold climate prevents the growing of
tropical decorative plants that are always so conspicuous in cities
and towns of the lower country. The gente decente, or upper class,
meet in the Plaza de Armas on Sundays for a chat with friends, a
stroll to exhibit their finery, and to listen to the music.
The Aymarás who inhabit the entire highlands are of a
treacherous disposition and have several times organized their forces
preparatory to making war on the Bolivians. As their number is very
great they are a menace that is very real and serious. When an
uprising is threatened, the chiefs are arrested and punished, and
then the rebellion dies down for want of leaders. These Indians still
retain the despeñadora, or death-doctor, in the more remote and
inaccessible regions. This person is a woman who possesses the
knack of doing away with the aged and infirm of her district, and the
office is handed down from mother to daughter. When any one
within her jurisdiction becomes too old to work, or is ill with a
malady thought to be incurable, the despeñadora is called in; she
straddles the poor unfortunate and ends his existence by deftly
dislocating the vertebræ of the neck. Whenever government officials

learn of the operation of one of these women, they are taken into
custody and punished.
One of the favorite sports of the Paceños is to hunt wild cattle in
the high valleys between the peaks. Numerous herds are still in
existence and it is said that they are of a savage disposition and
furnish good sport. I met an American who had been thrown from
his horse and gored by a wild bull that charged him from a distance
of several hundred yards.
The country between La Paz and Oruro is very similar to that we
had crossed coming from Guaqui. There are the same vistas of
barren plains, green fields, llamas, and asses on the slopes, and
dazzling snow-fields in the background. The plateau is strewn with
marine fossils, mostly trilobites, reminders of the days when Lake
Titicaca was many times its present size. We covered the one
hundred and twenty-seven miles to Oruro in six hours, and spent the
night there. This city owes its existence to the many mines located
near by—some within the city’s limits—and to the wealth they yield
in tin, silver, and other metals. Next morning the journey was
continued toward Cochabamba. Shortly before noon the level
country was left behind and we started down the eastern slope of a
ridge that leads into the lower country. This part of the road-bed is
new; the greater part of it is laid on a narrow shelf of rock carved
and blasted out of the mountainside. Perpendicular walls of granite
tower above to a height of hundreds of feet on one side; in places
the top of the huge masses seems to hang over the track in a
tottering position and one expects the rumble of the train to set it in
motion and bring an avalanche of destruction down upon one’s
head.
A small stream flows through the bottom of the gorge. During
the greater part of the year it is a mere rivulet that trickles
harmlessly over the shallow, pebbly bottom of its course; but when
the torrential rains of winter fall it rises rapidly to the proportions of
a mighty river and sweeps away sections of the railroad. Long rows
of breakwater have been placed alongside the base of the road-bed

to protect it from the ravages of the flood; they consist of loaf-
shaped piles of stone bound together with wire netting; these would
be effective against the water alone, but they cannot resist the
demolishing force of the huge boulders that are rolled down from
the mountains by the strong current.
A number of breaks in the line had been made by landslides just
before our visit, so the train could not proceed beyond Changollo, a
settlement of half a dozen Quechua Indian huts and a good-sized
station, the elevation of which is ten thousand feet. We were met by
a representative of the railway company and given quarters in the
station buildings; the other passengers immediately engaged mules
and llamas and started for Cochabamba. The reason for our delay
was that we had just received a shipment of ammunition and
supplies from New York, and some time would be required to repack
them in parcels of equal weight suitable for transportation by pack-
train.
Changollo was headquarters for the construction-gangs working
on the line. About half a dozen Englishmen and Scotchmen were in
charge of the work, and they showed us every possible courtesy and
attention during our brief stay there. I regret constantly that it is not
possible to give detailed credit to all the people, South Americans
and foreigners alike, who treated us with such unfailing courtesy
throughout our years of travel in the southern continent, and to
whose assistance we are so heavily indebted for the success that
attended our efforts; but to do so would fill the pages of a volume
several times the size of this one without leaving space for my
narrative.
All of the railroad men boarded with an Englishman named Cole
and his wife. The Coles were a middle-aged couple who had spent
the greater part of their lives together travelling around the world.
Among other places, they had lived in India and in Africa. They had
a score of parrots, cockatoos, and dogs that accompanied them in all
their wanderings; caring for this miniature menagerie must have
been a troublesome job while moving from place to place, but they

took the place of children and were looked after just as tenderly.
Cole claimed that he was the only man on earth who had been
bitten by a black mamba—a species of giant cobra—and lived to tell
the tale. He was following a path through the silent jungle one day
at dusk when a black form lunged down upon him from some
branches that overhung the trail; at the same time he felt a dull,
throbbing pain in his left arm, and realized what had occurred. His
first impulse was to flee in terror; however, better judgment
prevailed and he opened and sucked the wound and applied a
tourniquet above it. Then he hurried home and drank large
quantities of ammonia and also applied some to his arm. He stated
that he was very ill for several weeks but that persistent use of the
ammonia overcame the effects of the poison and he gradually
recovered.
Through the kindness of our new friends we secured hand-cars
on which to resume the journey to the end of the line—about ten
miles distant. The baggage was placed on some of them while we
occupied another. The way lay down-hill and we dashed along at a
great pace, taking curves without diminished speed. There were
several short tunnels, the entrances of which loomed up like the
black openings in a grotto; in a flash we were plunged into absolute
darkness; a moment later we raced back into bright sunshine.
Whenever an obstruction in the track ahead was sighted the brakes
were applied and then everything was carried around and the trip
continued. We met a good many Indians on the road-bed; they
preferred its use to the rocky trail along the river, and even drove
their burros and llamas on it. All employees of the company had
orders to punish any one found on the track, in order that they
might learn to keep off it, as there would otherwise be a great loss
of life when trains begin their runs over the line. The favorite form of
chastisement consisted of pouncing on the Indians and taking their
hats away from them. The head-gear was taken several miles down
the track and thrown into the top of a cactus or thorny tree. If the
offender resisted the seizure of his hat he was told that he might
have it by calling on the foreman of the nearest construction-camp;

when he arrived a good lecture was given him and in some instances
a fine was imposed.
It took several hours to reach the end of the line, as landslides
and the attendant portages around them had been numerous. We
spent the remainder of the day and the night at Arce, an Indian
village. Several hundred Quechuas had gathered, as it was market-
day; they brought a good deal of cloth and beautiful blankets to sell,
but their prices were several times those asked in more remote
regions. At night the assembly played on reed flutes and native
guitars, sang, danced, and drank chicha; the revelry lasted until the
first gray streaks of dawn appeared over the mountain-top, and then
the mob dispersed to their distant homes in the high valleys.
Our journey was continued the morning after reaching Arce. We
had secured a train of good, strong mules and expert Indian
arrieros. The trail lay along the river-bed, which was very wide and
paved with small pebbles. At numerous points Quechua women had
put up small shacks of stones and reeds; they squatted within the
makeshift shelters all day long. A white rag floating above from a tall
bamboo announced to the weary wayfarer that chicha was for sale
within, and all the travellers we saw religiously stopped at each of
these road-houses to slake their thirst. At one point a wall of rock
rises from the stream to a height of three thousand feet; two
condors were perched upon the very tip, their black forms clearly
outlined against the sky, while two others circled swiftly above. We
passed through the towns of Yberta and Sacamolla without stopping
to rest, and after fifteen and a half hours’ continuous riding reached
the home of the manager of the railroad, a Mr. Taylor, with whom we
spent the night. The place is called Parotani, and we subsequently
spent some time there investigating its interesting fauna. At noon on
the following day we reached Vinto, which marks the beginning of
an electric tram-line to Cochabamba. We did not take advantage of
this easy means of transportation, but continued the journey on
mule-back, and two hours later found ourselves at our destination.

CHAPTER XVIII
CROSSING THE BOLIVIAN HIGHLANDS FROM
COCHABAMBA TO THE CHAPARÉ
Cochabamba is one of the more important cities of Bolivia. In
size it ranks next to La Paz, although it is not nearly so modern, and
in point of activity it is far in advance of Sucre. The population is
about thirty-five thousand.
The plain upon which the city is built was at one time the bottom
of a lake, which fact is indicated by its ancient name of Oropeza, a
Quechua word meaning “plain of the lake.” On account of its high
elevation, which is approximately eight thousand five hundred feet
above sea-level, the region enjoys a mild climate; the average
annual temperature is 66° F. Rain falls in abundance during the
months from November to April; and during the dry months
irrigation is resorted to for providing water to the fields of alfalfa and
grain. The country is naturally of a decidedly semiarid character.
The city boasts a number of fairly modern buildings, although by
far the greater number are of the low adobe type with thatched or
tile roofs; delightful little plazas filled with tropical trees and
shrubbery relieve the monotony of the rows of white edifices.
The shops are filled with provisions and dry-goods at remarkably
low prices; the city market is supplied with a superabundance of
produce, flowers, and articles of native manufacture; the people are
courteous and obliging, and the great numbers of Indians and

Cholos give a touch of gayety and color to the throngs which fill the
streets.
Among the city’s institutions deserving of special mention is the
Cochabamba Institute, founded in 1911. The instructors are nearly
all Americans of the type one meets all too rarely in South America,
and who are really doing a great and noble work in furthering the
educational and moral progress of the country. Several hundred
students of both sexes, from many and remote parts of Bolivia,
attend the literary and business classes of the college, live under the
care and refining influence of its instructors, and, as I subsequently
discovered, introduce into their homes the desirable and elevating
qualities which they have acquired.
To the northwest towers the Cerro Tunari, a mountain over
fifteen thousand feet high and of imposing appearance. It rises in
majestic proportions above the uneven summits of the cordillera, in
a manner befitting a snow-crowned monarch of the range.
We spent several days in the city, adding to our outfit and
purchasing mules, and then started eastward en route to the Beni
district; it was our intention to go slowly and stop at places which
offered a suitable field for our operations.
Leaving Cochabamba on the afternoon of May 9, 1915, we rode
the fifteen miles to the town of Sacaba, arriving there at dusk. The
intervening country is thickly settled, and large areas are irrigated
and planted in alfalfa, maize, wheat, grapes, and vegetables. Nearly
all the inhabitants are Indians of the Quechua race.
Beyond Sacaba the trail adheres closely to the bed of a small
stream, and ascends at a steep angle. Numerous little canals carry
the water along the mountainside, and the country is dotted with
small stone huts surrounded by carefully cultivated fields; this is
made possible by the fact that the rivulet never dries, but, on the
contrary, supplies a constant stream of water of sufficient volume to
irrigate a large area. The canals have been dug with great precision;

each family uses only as much as required, and at stated intervals,
so there is enough for all.
The trail goes up steadily until an elevation of twelve thousand
feet is reached. As we neared the top a strong wind sprang up, so
that it was difficult to keep one’s place in the saddle. The
mountainside is covered with small, round rocks of uniform size,
such as one would usually expect to find in a dry river-bed.
Beyond the high summit of the first ridge lies the high mountain
valley in which is located the Quechua village of Cuchicancha
(meaning “pig-pen”). There are several score of huts scattered about
in little groups, and built of rocks, with thatched roofs. The Indians
speak practically no Spanish, and live in much the same way as they
did in the days of Atahualpa. In order to cultivate the land they have
gathered the rocks which everywhere carpet the ground into huge
piles, and also built fences of them; large quantities of potatoes,
ocas, and avas are grown.
Each family owns a flock of sheep, which apparently replace the
llamas of olden days, although flocks of the latter animals are still to
be seen frequently; also a few pigs and burros. They have likewise
taken to cultivating wheat, oats, and rye.
We decided to spend a week at Cuchicancha and succeeded in
persuading an old Quechua man to rent us his hut for that length of
time. He spoke not a word of Spanish, or at least pretended that he
knew nothing whatever of that language, so all conversation had to
be carried on through an interpreter. As our coming was a complete
surprise to him, he asked if he could occupy the habitation with us
for a few nights until he had time to find sleeping-quarters
elsewhere; to this we, of course, consented. One night I was
awakened by loud talking, and much to my astonishment found that
the aged Indian, who had evidently taken too much chicha during
the day, was restlessly tossing on his pile of sheepskins and
blankets, and talking in his sleep—in excellent Spanish. After that we
conversed with him without the aid of an interpreter, and he
understood every word of it, too.

The weather at Cuchicancha was splendid; it was autumn, and
while the nights were cold, the days were always comfortably warm.
The Indians were friendly and brought us eggs, goats’ milk,
chickens, and bread. Each morning the children took the flocks to
the narrow river-bed to feed on the sparse vegetation, and at night
they brought them back to the stone corrals; they took a few boiled
potatoes with them for lunch, and also their spinning for pastime. All
spin except the men; and every one had an abundance of blankets
and ponchos; even the bags for grain and potatoes are made of
homespun wool.
The harvest had been gathered and every one seemed
contented. One day a party of Indians collected to thresh wheat;
from a distance I could hear the boom of a drum and the shrill wail
of reed flutes; as I approached, a strange sight met my eyes.
Bundles of grain had been piled in a high mound, on the top of
which sat the musicians; a dozen mounted Indians were driving a
herd of mules and burros around the base. Around and around they
went at a frantic pace, keeping perfect time with the music; as the
animals circled the stack a man on top cast armfuls of wheat down
in their path, so that in running over it repeatedly they naturally
trampled out the grain. About a hundred men, each holding to a
long rope, formed a circular fence around the racing mob and
prevented any of the animals from escaping.
We were surprised at the abundance of life in this naturally
barren region. There were practically no indigenous trees, but a long
line of willows had been planted near one of the houses, and to
these thousands of cowbirds, doves, and finches came each night to
sleep. A short walk across the stubble-fields always revealed
something new. There were tinamou which rose with a loud whir,
reminding one of partridges; many species of brownish birds
belonging to the wood-hewer family, one of them with a long,
curved bill, but they ran about on the ground or perched on the
stone fences; large flickers lived among the rocks, and condors
soared above; and there were even flocks of gulls and plovers. The
most unusual birds were two species of very small parrakeets which

clambered about over the rocks and slept in holes in the high banks.
Vast numbers of cavies lived in the rock-piles, from which they
sallied at all hours of the day in quest of food, and many small
rodents inhabited the grain-fields.
A good trail leads eastward from Cochicancha; the summit of the
range rises about two leagues from the settlement. At the time of
our visit the black, rocky peaks were covered with a mantle of snow
and an icy wind swept through the cleft which serves as a pass. The
elevation of the trail is thirteen thousand four hundred feet. At the
base of the towering masses which rise several hundred feet above
the passage, lies a placid little lake, and ducks, and gulls were
swimming on its peaceful surface. Condors swept down from above
to inspect us, and then soared back to their dizzy perches among
the unscalable crags.
On the eastern side of the divide the trail leads downward
abruptly, and the character of the country changes; at eleven
thousand feet a sparse growth of bushes appears, growing denser
with each passing mile. Suddenly we found ourselves on the rim of a
gorge through which the Incachaca River rushes—a raging mountain
torrent fed by snows melting in the high altitudes. The path is a
mere shelf cut in the face of the cliff; to the left rise the smooth
walls of frowning, black rock; to the right is a sheer drop to the river.
We could peer over the edge of the precipice and see drifting clouds
two thousand feet below, filling the chasm and shutting from view
the bottom hundreds of feet lower down.
At seven thousand seven hundred feet the forest begins; a
collection of half a dozen huts called Incachaca nestles in its inner
border, and there we decided to remain for a few weeks. We secured
space in a large house belonging to an organization which is
engaged in digging a canal along the opposite side of the gorge;
when this work is completed the water of the river will be turned
into the artificial course and utilized for running dynamos to furnish
electricity for the light and street-car service of Cochabamba. A
power-house had been constructed at the bottom of the ravine, and

the lines for transmitting the current had been strung across the
mountains.
At Incachaca the river flows through an underground channel;
while exploring the forest one day we came suddenly upon the
narrow cleft in the mountainside, scarcely a dozen feet across, and
with a great deal of effort were finally able to distinguish the roaring
white torrent a hundred feet below. The edges of the cleft are so
overgrown with ferns that one has no idea of its existence until the
very brink is reached. A short distance below, the river emerges
from the darkened cavern, and plunging over the face of a precipice,
thunders into a pool in a sheer drop of fifty or sixty feet.
We found the upper limit of a subtropical fauna at Incachaca.
Bird-flocks travelled hurriedly through the trees; they were
composed of bright-colored tanagers, finches, and cotingas. Honey-
creepers and hummers were plentiful in the flowering shrubs. Queer
little ducks called merganettas disported in the pool below the falls,
and dippers ran nimbly along the edge of the water. In one of the
tall trees near the river we discovered the nest of an eagle. We
found it impossible to climb the tree, but a German named Ricardo
Marquardt, who was in charge of the workmen along the river,
succeeded in reaching the huge mass of sticks seventy feet above
the ground, and brought down a beautifully spotted egg. To my
companion, Mr. Howarth S. Boyle, who accompanied me on the
entire trip, belongs the credit of taking the rarest birds from this
locality; they were a pair of white-eared thrushes (Entomodestes),
which, so far as I can learn, exist in only two other museums.
Among the lower growth lived many ant-thrushes (Grallaria), whose
clear call could be heard at all hours of the day. This is one of the
hardest of all birds to collect. The long-legged, tailless songsters
never leave the thick growth of ferns and brush, and the only way to
secure them is to enter the dense cover, sit quietly, and imitate the
clear, ringing call in the hope of attracting the birds; sometimes this
requires hours of patient work, and more often than not the effort is
futile.

Coatimondis, or raccoons, roamed in the woods in small bands,
sniffing in the damp mould and searching for insects; while feeding
they uttered deep grunts, but when frightened they gave a
succession of rapid bird-like chirps. These animals spend a good deal
of their time in the trees, but are almost invariably found on the
ground in the daytime; when pursued they are very pugnacious and
it takes an exceptionally agile dog indeed to avoid being severely
torn by the sharp teeth and claws. In captivity they become very
tame, and make nice little pets, although their mischievous
disposition often gets them into trouble.
From Incachaca to Locotál is a distance of only eight miles, but
the scenery along a part of the route is as impressive as any to be
found in the entire Andean chain; perhaps the gorge of the
Urubamba, in Peru, alone equals it in grandeur and awe-inspiring
magnificence. The bare, shattered, and split crags reach many
hundred feet above the trail, and stand in a leaning position so that
the tops actually hang over the narrow passageway as if threatening
to topple over at any moment; below, the steep slope is covered
with huge boulders which have fallen from the towering masses
above.
At Locotál there are but half a dozen houses, occupied by
Quechua families who subsist mainly on the profits derived from the
sale of chicha. We stopped a few days in a hut owned by a kind-
hearted old woman who gave us permission to use it; next day we
found that we were occupying the schoolroom, and the teacher
followed by his half-dozen ragged scholars came to take possession.
He tried to show us how important it was to have the place at once,
but we saw no reason why he could not conduct his class out under
the trees just as well as under the shelter; this suggestion offended
him very much, so greatly to the delight of the pupils he declared a
vacation until the gringos should move on.
Chicha, the native drink of Quechuas and Bolivians alike, is a
kind of corn-beer; it is made by grinding maize into a fine meal,
after which the women and children thoroughly masticate a part of

it; water is added to the mass and the thick liquid is boiled several
hours, after which it is poured into jars to ferment; it is of a yellow
color, has a tart, agreeable taste, and is intoxicating.
The forest at Locotál is somewhat taller than at Incachaca, but
the birds are of a similar character. Very abundant and beautiful
were the brilliant cocks-of-the-rock; the bright, orange-red creatures
flashed through the deep green of the forest like fiery comets and,
perching on the low branch of a tree, quietly surveyed their
surrounding, or uttered hoarse, croaking calls. This bird is most
conspicuous in its natural environment. Among the other large birds
were green toucans (Aulacorhynchus); the natives hunted them on
every possible occasion for the sake of obtaining the bill, which they
use as remedio, the rasping sound made by rubbing the mandibles
together being supposed to be an unfailing cure for epilepsy.
While pursuing our work at Locotál, a man named Quiroga
chanced to pass, and begged that we pay him the honor of stopping
at his house some distance below; it was a charming place, he said,
in the very heart of the wonderful Yungas. We gladly accepted his
invitation, and one morning loaded our outfit on mules and started
down the trail. For a mile there is only a narrow ledge in the face of
a rounded mountain of dark sandstone; a few stunted sprouts, and
myriads of orchids covered with purple blooms, have secured a
precarious foothold in crevices in the glazed surface; hundreds of
feet below, but invisible, the river tears through a narrow gorge. At
one point a strip of the shelf upon which we travelled had entirely
disappeared; we could not see the bottom of the canyon—its depth
was too great—but there were evidences we could not mistake,
telling us the history of the gap in the trail. Vultures hovered over
the spot and perched on the scant vegetation, and from below came
an overpowering stench. What more was needed to reveal the fact
that the missing section of trail, in its mad dash through space, had
taken with it the pack-train of mules, and probably the men
attending them, which chanced to be passing at the time.

Miguelito is only three miles below Locotál, and consists of three
or four huts in the centre of a grassy clearing. The Quechuas who
live there are friendly, and one may be sure of a welcome for a
night’s stop.
At five thousand five hundred feet the forest becomes taller and
the trees attain a greater diameter. The vegetation of the subtropic
zone reaches its highest development at this altitude. After crossing
a ridge six thousand seven hundred feet high, the trail descends a
long slope into the Yungas, properly known as the Yungas of
Cochabamba. At the base of the ridge, and shortly before entering
the cultivated area, we crossed the dry, narrow bed of a stream
which was filled with rocks bearing the imprints of leaves, and also
fossil shells.
Yungas is the name given to the fertile mountain slopes which
have been cleared of forest and cultivated; it stretches along the
sides of the Rio Yungas for a number of miles, and huts dot the
roadside at frequent intervals. When we visited the region in June
only the Indian caretakers lived in the habitations, the coca, which is
the principal product, having been collected a short time before, and
the propietarios having gone back to Cochabamba. The owners visit
their plantations three times a year, supervise the picking and
packing of the leaves and, after a month, return to Cochabamba to
sell the drug and live on the proceeds until the next harvest.
After spending an hour in questioning the occupants of the
various houses which we passed, we succeeded in locating the
house to which we had been invited. It was a low, one-room board
structure, open at both ends, and with wide entrances on each side,
situated in the centre of a large banana-field. An Indian, so old that
he could hardly walk, lived in the hovel and refused to admit us;
however, we flourished our letter of introduction from the owner of
the premises, took possession, and remained a week. When we left,
the aged tenant implored us to remain, as we had daily provided
him with all the game he could eat, and had provided him with some
medicines that he greatly needed.

The climate at this season, June, was most trying. Although the
elevation is only three thousand five hundred feet, the whole region
was covered with fog each night, and the cold and damp penetrated
everything; during a part of the year the weather is good, and then
life in the Yungas is more bearable. We had a trying time at Señor
Quiroga’s hut, and while the pleasure of investigating a new region
is always intense, our joy at leaving was in this particular instance
vastly greater.
There is no flat valley along the river, which is of considerable
size, and all cultivation is done on the steep mountainsides. Coca is
planted in terraces and occupies the greatest acreage; then there
are red bananas, plantains, guavas, and sugar-cane.
The fauna of the country seems to represent a transition zone.
There are birds typical of the higher country, and others which are
common lower down; also, a number found at approximately this
altitude only. Near the house, and on the edge of the banana-
plantation, was a tall, isolated tree. Flocks of birds, in their flight
from one side of the canyon to the other, would invariably alight in
its branches for a few minutes’ rest. There were many brilliantly
colored little tanagers (Tanagra) which came to the tree in
considerable numbers and chirped and quarrelled as they flitted
about examining the leaves for insects, or reached out to pick the
small fruits with which the tree was covered; one day not less than
seven species of these birds visited this resort within a short time.

An Indian hut in the Yungas of Cochabamba.
Giant orioles (Ostinops) were also very plentiful, and travelled in
large, noisy flocks. One of the more interesting birds was a species
of small, red-tailed parrakeet (Pyrrhura) which clung to and crawled
up the sides of trees like squirrels; it was almost impossible to see
them unless they moved, so well did their coloration, and more
particularly their actions, conceal them.
We had travelled to the Yungas on mules owned by the
expedition, and upon our arrival turned them loose to feed as usual.
Next morning the animals were in a sorry plight; they had been
visited by vampire-bats during the night, and bled so badly that we

had to send them back to Locotál without delay. Severe as this
attack seemed to be, it was mild compared to what we were to see
later on. We discovered clumps of the small bats guilty of the
execution spending the days under the roof of our hut, and
despatched many of them, but this made no impression whatever
upon their vast number. People, also, are bitten on any part of the
body which is left exposed at night, and I have frequently seen
Indians which had been attacked on nose, forehead, and arms.
After completing our work in the Yungas we returned to
Cochabamba in order to await more favorable weather for the trip
into the lowlands of eastern Bolivia, and to restock our outfit with
articles which had been used, and others which it seemed necessary
to acquire for the difficult undertaking ahead.
After spending several weeks in the vicinity of Cochabamba, we
made arrangements with the mail-carrier which enabled us to travel
jointly to the Chaparé. He usually made the trip at six weeks’
intervals during the dry season, and, consequently, he knew the trail
better than any one else. His peons were also accustomed to the
country and knew how to adjust packs so they would meet the
varying conditions of the road, which is an “art” that can be learned
through long experience only.
On July 12 we left Cochabamba. Besides my companion and our
personal attendant there were the mail-carrier and his three peons;
twelve good, strong mules carried the luggage, and there were half
a dozen riding and spare animals—quite a cavalcade for the kind of
undertaking in hand.
Three days after starting we reached our old camping-spot in
the Yungas, and, after stopping for a short chat with the old
caretaker of Señor Quiroga’s hut we proceeded into what was for us
terra incognita.
Numerous huts of flimsy construction are scattered along the
entire twenty miles or more of cultivated slopes; each has a fenced-
in area paved with flat stones upon which coca leaves are dried. We

stopped at a number of these dwellings in an attempt to buy fruit or
vegetables, but unfortunately the men were all away working in the
fields, and any one who has attempted to purchase anything from
the average Quechua squaw knows how hopeless a task it is.
Although they may have a superabundance of the article desired,
they seem to take great delight in refusing to sell anything to a
stranger; then the only method to follow is to take what is needed,
offer a fair price for it and pass on, leaving them in the midst of their
wild rantings; the men are easier to deal with.
The peons, and the patrón as well, stopped at each hut where
the white flag announced that chicha was for sale, and attempted to
drink enough to last them until their return; after their money gave
out they left articles of clothing in payment for the drinks. It was
therefore a great relief when the last abode of the intoxicating
beverage had been left behind, and we plunged into the wilderness.
Immediately after leaving the Yungas we ascended a precipitous
slope, the top of which was seven hundred feet above the
surrounding country, and then descended on the other side until the
elevation was only two thousand feet; here the forest was more
tropical in character, and some of the trees, especially the
cottonwoods, reached a height of one hundred and fifty feet, and
measured twenty-five feet through the buttressed roots at the base.
The day after leaving the Yungas we reached the most
dangerous part of the whole trail. After crossing a number of steep,
high ridges, we came to an abrupt slope, the side of which is seared
by a huge gash where the treacherous white clay keeps sliding
constantly into the river, many hundreds of feet below. Each caravan
desiring to pass must first cut a ledge in the moving mass of soft,
muddy earth, and then hurriedly lead the mules across, one at a
time, before the newly made trail is obliterated. The spot is very
appropriately named Sal-si-Puedes (pass if you can), for any one
succeeding in crossing this slide is very apt to possess the ingenuity
required to negotiate the remainder of the trail.

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Advances In Renewable Hydrogen And Other Sustainable Energy Carriers Abdallah Khellaf

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Advances In Renewable Hydrogen And Other Sustainable Energy Carriers Abdallah Khellaf

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