STUDIES ON PHOTOELECTROCHEMICAL BEHAVIOUR OF CERTAIN OXIDE MATERIALS FOR PHOTOASSISTED ELECTROLYSIS OF WATER.

The photoelectrochemical (PEC) characteristics of certain n-type oxides viz. Nb//2O//5, TiNb//2O//7, Ti//2Nb//1//0O//2//9 and CoNb//2O//6 in polycrystalline form have been investigated for use as anodes in photoelectrolysis cells to produce hydrogen. Thin films of Nb//2O//5 formed by heating Nb and sintered compacts of the oxides have been studied. Photoelectrolysis of water is observed at potentials close to the photo-onset for Nb//2O//5 film on Nb and at slightly more positive potentials for sintered electrodes. Photoresponse, quantum efficiency and capacitance measurements are reported. Effect of cathodic potential on the photo and dark current-voltage behaviour of Nb//2O//5 thin film and sintered compacts also has been discussed.