Studies on Some Bioinspired Materials in Solar Energy Induced Water Splitting for Hydrogen Generation

Abstract

For the expansion of the sustainable energy based society, photoelectrochemical (PEC) water newlinesplitting is considered as a promising approach to effectively diminish environmental issues newlineresulted from fossil fuels combustion by replacing it with hydrogen, a clean fuel obtained from newlineexploiting two copiously rich energy sources viz., sunlight and water. However, this technology newlinesuffers substantial setback in its application due to sluggish water oxidation kinetics taking place newlineat the surface of photoanode due to critical water oxidation half-cell reaction demanding four newlineelectrons. newlinePhotosynthesis is known for storing light energy into the chemical bonds and the driving force of newlinethis process is the splitting of water by sunlight for which nature has evolved oxygen evolving newlinecomplex (OEC) supported by manganese clusters that efficiently catalyzes the water oxidation. newlineInspired by the nature s machinery, the present thesis explores the integration of bioinspired water newlineoxidation catalysts (WOCs) such as cobalt- acetate (Co-Ac), cobalt-phosphate (Co-Pi) and ferric newlineoxyhydroxide (FeOOH) on doped and undoped small bandgap nanostructured photoanode viz., newlineFe2O3 and BiVO4 in order to overcome the limitations directed towards kinetic barrier, newlineoverpotential along with poor charge carrier dynamics associated with these metal oxides. newlineMethods like Electrodeposition and spray pyrolysis were used for preparation of nanostructured newlinemetal oxide photoanodes whereas the catalyst fabrication was achieved by photoelectrodeposition newlineroute. Obtained catalyst fabricated films showed dramatic cathodic shift in the newlineonset potential indicating reduction in the overpotential needed for water splitting along with newlinesignificant enhancement in photocurrent density in comparison to the pristine (without catalyst) newlinesamples. Various studies were conducted on fabricated and pristine samples to establish the role newlineof bioinspired catalyst in the solar energy driven water splitting. A dramatic shift in onset potential newline~300mV was observed in Co-Ac modified Ti-Fe2O3 sa