Development of Surface Engineered Nanostructured Photoanodes for Enhanced Photo Electrochemical Processes

A number of metal oxide semiconductors based photoelectrochemical processes have been utilized in environmental and energy related application. With increased urgency in the search for alternative sources of energy, photoelectrolysis of water for generation of hydrogen using solar radiation has attracted great attention. Several metal oxide semiconductors have been considered as promising materials for photoelectrochemical generation of hydrogen. They are photostable, chemically inert, and cost effective. However, most stable semiconducting electrodes have large band gaps and hence low efficiency for photo-conversion for the entire spectrum of solar radiation. Reduction of band gap by doping the bulk of the semiconductor has not been found successful since such a process introduces charge carrier traps and compromises electron conduction and material durability. Vertical and ordered nanotubular titania (TiO2) arrays were synthesized by electrochemical anodization of Ti thin foils. Plasma surface doping of TiO2 nanotubular photoanodes resulted in a significantly enhanced photocurrent density.