bionic leaf

1. Artificial Photosynthesis Bio-mimetic photo catalysis Basil Jose S7, CHE

2. Under the guidance of Asst. Prof. Anoop S S Department of Chemical Engg AmaJyothi College of Engineering Department of Chemical Engineering 2

3. Department of Chemical Engineering 3 Introduction The Energy challenge Solar power Photosynthesis Light and dark reactions Mimicking the grand design Scale up Sustainable future Reference Table of Contents

4. A simple thought to begin with… Department of Chemical Engineering 4

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7. Willem Alexander Department of Chemical Engineering 7 “With the help of the sun we could solve our energy problem Every thirty minutes the Earth absorbs enough sunlight to supply the whole world a year long with energy Every thirty minutes! This is where our challenge is We have to use this potential This is where we can use the forces of nature to our advantage”

8. Department of Chemical Engineering 8 The Gemasolar plant in Spain. Source: http ://www.torresolenergy.com/TORRESOL/gemasolar-plant/en

9. Short comings at present Photovoltaic cells remain expensive Sunlight is a weather dependent energy source Need to design more efficient storage devices Department of Chemical Engineering 9 So we go to an ancient practice called BIOMIMICRY

10. Department of Chemical Engineering 10 16 TW can only be attained if we listen to NATURE

11. Department of Chemical Engineering 11 Plants listen to the sun

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13. Department of Chemical Engineering 13 The light reactions 1. Photophosphorylation 2H2O + NADP + +3ADP + 3P  2NADPH + H + + 3ATP + O2 NADP + : Nicotinamide adenine dinucleotide phosphate ADP : Adenosine diphosphate NADPH : stored form of Hydrogen ATP : Adenosine Triphosphate : C10H16N5O13P3 Takes place in thylakoid membranes in the interior of chloroplasts

14. Department of Chemical Engineering 14 The light reactions 2. Calvin Cycle RuBP carboxylase enzyme RuBP : Ribulose biphosphate G3P : Glyceraldehyde-3-phosphate Uses reducing power of NADPH And free energy stored in ATP to assimilate CO2 In form of carbohydrates CO2 + RuBP  2(3-phosphoglycerate) 3-phosphoglycerate  (glucose)

15. Department of Chemical Engineering 15 Δ G=522kJ/ mol Already have technology to capture sunlight Already have fuel cells to generate electricity Effective means to break down water using sunlight…?

16.   N ature’s own system Department of Chemical Engineering 16

17. Department of Chemical Engineering 17 Energetic barrier of water oxidation : 1.23V

18. Artificial Photosynthesis - steps Light harvesting Charge separation Water splitting Fuel production Department of Chemical Engineering 18 Collection of light particles (photons) by antenna molecules and the concentration of the collected energy in a reaction center. C ollected sunlight is used to separate positive (‘holes’) and negative (electrons) charges from each other at the reaction center Positive charges are directly injected into catalytic centers where they are used to split water into hydrogen ions (protons) and oxygen. Electrons from step 2 are given more energy from new photons and subsequently combined with the hydrogen ions and possibly CO2 to produce either hydrogen or a carbon-based fuel. Anode(Oxidation): 2H₂O → 4H⁺ + 4e⁻ + O₂

19. Department of Chemical Engineering 19 NiMoZn used to reduce cost Co-OEC : cobalt-oxygen evolving complex , Deposits oxygen at anode side (on illuminated side of cell) ITO(Indium tin oxide) layer : A conducting metal oxide layer to stabilize silicon in water Si : Act as light harvesting catalyst. Captures solar light. NiMoZn : Produces H ₂ from combining H⁺ & e⁻ M ade available from semiconductor at cathode side . Stainless steel : Used for support . Si is deposited on it.   silicon strip coated with catalysts on each side Triple junction

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21. Department of Chemical Engineering 21 Source : Royal Society of Chemistry

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24. Department of Chemical Engineering 24 The dream is to make each home its own power station One can envision sustainocene not long from now Purchasing an affordable basic power system based on this gift from nature A gallon of water and continuous sunlight ;all it needs to power a house for a day 2.5 billion years of evolution

25. References Thomas Hauch (2011), Artificial Photosynthesis Looking to Nature for Alternative Energy , Dartmouth U ndergraduate Journal of science. , pp 14-15 Michael Gràetzal (Aug 1999), The artificial leaf-Bio-mimetic photo catalysis , Baltzer Science Publifhings . Vol 3(1), pp 4-18 Alexandre De Spiegeleer , Bastian Schiffthaler , Hanna Rademaker , and Tomas B¨acklund , The artificial leaf. Robin Purchase , huib de vriend en huub de groot(2015), Artificial photosynthesis , Groene Grondstoffen Han Zhou, Xufan Li, Tongxiang Fan, Frank E.Osterloh , Jian Ding, Erwin M.Sabio , Di Zhang and Qixin Guo (2010), Artificial Inorganic Leafs for efficient photochemical hydrogen production inspired by natural photosynthesis , Advanced Materials, pp 951-956 Joseph Hupp(2011), Nanostructured Architectures and “Artificial Leaf” Solar Cells , Materials Seminar(Arizona State Univ.), GWC 465 Sergey Koroidov (2014), Water splitting in natural and artificial photosynthetic systems , Dept. of Chemistry Thesis(Umea Univ.), ISBN: 978-91-7459-800-1 Steven Y. Reece, Jonathan A. Hamel , Kimberly Sung , Thomas D. Jarvi , Arthur J. Esswein , Joep J. H. Pijpers , Daniel G. Nocera (Nov 2011), Wireless Solar Water Splitting Using Silicon-Based Semiconductors and Earth-Abundant Catalysts , SCIENCE , pp 645-647, 789 , 925-927, Department of Chemical Engineering 25

26. Department of Chemical Engineering 26 1 litre = 13 kW

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