Novel Approaches to Enhanced Photocatalytic Water Splitting for the Production of Solar Fuel (Hydrogen) Using Materials Based on Cerium Oxide (CeO2)

Cerium oxide (CeO2) nanoparticle material exhibits exceptional performance in H2 evolution when used as a catalyst for photocatalytic water splitting. Numerous nanostructures, including nanorods, nanowires, nanosheets, nanotubes, and nanoflowers, are home to CeO2 nanoparticles. On the other hand, because of its ~2.8–3.2 eV band gap, it has the disadvantage of photocorrosion and a response to the visible light area in the UV and visible light. Unresolved characteristics of CeO2 include its high cost and rarity in nature. However, it has the advantages of radiation, chemical stability, thermal stability, and nontoxicity. Currently, a number of methods for synthesizing CeO2 nanoparticles have been modified; adding metal oxide, sulfide, or other materials to CeO2 nanoparticles enhances their functionality. Mechanism of S-scheme, Z-scheme, and direct S-scheme nano composite heterojunction based on CeO2. Additionally, p-n junction band alignment engineering was clearly covered. Due to the current global energy and climate crises, as well as environmental issues, H2 energy will continue to exist as an auxiliary energy vector. However, an evaluation of the future prospects of CeO2-based photocatalytic H2 generation via water splitting was conducted. It was observed that CeO2 nanoparticles may couple with metal oxide, 2D material, and metal sulfide to divide PC water.

1. Novel Approaches to Enhanced Photocatalytic Water Splitting for the Production of Solar Fuel (Hydrogen) Using Materials Based on Cerium Oxide (CeO 2 ) Mam Ishaku Dagareh, Hafeez Yusuf Hafeez, J. Mohammed , Adamu David Gaima Kafadi , Abdussalam Balarabe Suleiman, Chifu Ebenezer Ndikilar Advanced nanotechnology and computational Laboratory R esearch Group Department of Physics, Federal University Dutse P.M.B. 7156, Ibrahim Aliyu Bye-Pass, Jigawa State Nigeria institute of physics 45 th annual conference on Physics Advancement pathway to economics and technological development. Bayaro University kano , Faculty of physical Sciences (Physics Department) 5/9/2024 1 6 th -10 th May, 2024 1

2. 5/9/2024 2 Overview of the Presentation Section 1 Energy Crisis and Demand Section 2 photocatalysis Section 3 Why Cerium oxide nanoparticle ? Section 4 Synthesis and crystallographic structure of CeO 2 Section 5 Empirical review

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4. INTRODUCTION 4 Energy crisis Renewable energy Carbon emission Hydropower Wind energy Geothermal e.t.c Green hydrogen 140 MJ/Kg Infinite Eco-friendly Burning to yield water Method of hydrogen production Electrolysis Thermolysis photolysis Photochemical Photocatalysis photobiological Metal oxide Photocatalysis is cynosure Photocatalytic Hydrogen evolution 5/9/2024 Climate Change Acid Rain & Air Pollution

5. 5/9/2024 5 The catalyst which work in the presence of light (photon) of energy is known as Photocatalyst and this phenomenon is called Photocatalysis .

6. Requirements of a Photocatalyst for hydrogen production Must have band gap energy greater than 1.23 eV and less 3.0ev, well crystalline and high surface area Conduction Band of semiconductor must be more negative than the redox potential of Hydrogen and Valence Band must be more positive than oxidation potential  of Oxygen Resistance to photo-corrosion 5/9/2024 6 Electron-hole pair recombination separation and transportation of carrier inextensible to visible light photon

7. 5 Cerium oxide n -type Bandgap 2.8 eV-3.2 eV Visible & UV-region Photocorrosion Recombination -2 -1 1 2 3     0.1eV 3.1ev CeO 2 radiation resistance, Nontoxicity high chemical thermal stability Simplistic synthesis 5/9/2024

8. 5/9/2024 8 C rystal structure of CeO 2

9. HYDROTHERMAL SYNTHESIS OF CeO 2 5/9/2024 9

10. Approaches to prevent electron-hole pair recombination via Heterojunction construction Doping with metal Use electron mediator i.e rGO 5/9/2024 10

11. heterojunction Fig. 13 Schematic illustration of p-n junction Fig.14 (a) Schematic illustration of liquid phase and all solid Z-scheme 5/9/2024 11

12. Fig.14 (b) Schematic illustration of direct z -scheme 5/9/2024 12 S-scheme

13. 6.1 Water splitting by CeO 2 /metal-oxide composites Table 2 . Cerium oxide / metal oxide 5/9/2024 13 S/N Main catalyst Co-catalyst Source light Method Amount of H2 [mmol h− 1g− 1] Reference   1 TiO 2 CeO 2 500W Xenon Sol-gel 0.182 [51]   2 Ag-ZnO CeO 2 300W Xenon combustion method 18.345   [53]   3 CeO 2 Fe 2 O 3 100 W Xenon lamp Thermal decomposition method, 583.7 [57]   4 Co 3 O 4 CeO 2 5w white 420nm one-step solvothermal method 2.29852 [28]   5 Cu-CeO 2   Xe lamp Hydrothermal 18.4 [39]   6   CeO 2 SnO 2 300 W Xe lamp hard template method, sol-gel 6.2677 [59]   7 TiO 2 CeO 2 80 Xe lamp Hydrothermal, solvothermal method 29.37 [66]   8 Fe-CeO 2   125 W Hg lamp Hydrothermal 641 [67]   9 W 18 O 49 CeO 2 300 W Xe lamp Hydrothermal 0.2061 [72]   10 ZnO CeO 2 300 W Xe lamp Hydrothermal 0.2061 [73]   11 CeO 2 CeVO 4 /V 2 O 5 300 W Xe lamp Sol-gel, isoelectric point method and solid phase reaction method   189.7 [74]   12 ZnO CeO 2 -Ag 300 W Xe lamp Hydrothermal 3.1420 [75]   13 CeO 2 ZrO 2 300 W Xe lamp Template strategy 0.05 [97]   14 CeO 2 nanorods   300 W Xe lamp Hydrothermal 0.005 [100]

14. 6.2 Water splitting by CeO2/metal-sulfides composites Table 3: CeO 2 and sulfides 5/9/2024 14 S/N Main catalyst Co-catalyst Source light Method Amount of H2 [mmol h− 1g− 1] Ref erence   1 CeO 2 CdS 300 W Xe lamp Hydrothermal 0.22975 [21]   2 O v -CeO 2 CdS 300 W Xe lamp Wet chemical method 12.9 [64]   3 ZnS CeO 2 300 W Xe lamp Precipitation 0. 417 [26]   4 CeO 2 CdZnS 300 W Xe lamp Solvathermal Hydrothermal 0.02211 [76]   5 CdS CeO 2 300 W Xe lamp Precipitation 0.0701 [82]   6 Fe-CeO 2 CdS 225 W Xe lamp Hydrothermal 108.9 [87]   7 CeO 2 MoS 2 150W Xe lamp Hydrothermal; 0.1125 [95]   8 CdS Pt/WO 3 -CeOx P 300W Xe lamp Precipitation 0.041 [99]

15. 6.0 Water splitting by CeO 2 /2D-materials composites Table 1. Cerium oxide / 2D material 5/9/2024 15 S/N Main catalyst Co-catalyst Source light Method Amount of H2 [mmol h− 1g− 1] Reference   1 CeO 2 g-C 3 N 4 Visible light Electrospinning and vapor deposition 0.22975 [21]   2 CdSe CeO 2 300 Xenon lamp Physical mixing method 0.83 [49]   3 Co-CeO 2 g-C 3 N 4 225 W Xenon lamp Thermal polymerization. solvothermal method, self-assembly method 1.07702 [26]   4 CeO2 CdS 300 W Xe lamp Hydrothermal 14.84 [41]   5 CeO2 g-C 3 N 4 300 W Xe lamp pyrolysis 1240.9 mol g−1 h−1, [110]   6 CeO2 MnO2     (540 μmol h− 1 ) [111]

16. Summary and conclusion of CeO 2 nanoparticle 16 Hydrothermal method Ternary photocatalyst Enhance photocatalytic hydrogen evolution 5/9/2024

17. 5/9/2024 17 Thanks for your time Mam .I Dagareh Thanks for listening [email protected]

18. 5/9/2024 18 Acknowledgements Dr. Hafeez Yusuf Hafeez, HOD, Department of Physics, FUD Advanced nanotechnology and computational Laboratory research team Nigerians Institute of Physics (NIP) All staff of Department of Physics of Federal U niversity Dutse Nigeria Bayaro University kano , faculty of physical science ( Physics Department) The World Academy of Science (TWAS)- Germany Seed Grant for New African Principal Investigators (SG-NAPI): 4500454078

19. Under review, will be published at cost of the year A recent advancements in Cerium Oxide (CeO 2 ) Based materials for efficient photocatalytic water splitting to produce solar fuel (Hydrogen) A Review on Zinc Oxide (ZnO) Based Composites for Photocatalytic Hydrogen Production via Water-splitting 5/9/2024 19

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