Hydrogen Production through Photoelectrolysis

Abstract

Because of being a perfect substitute for the fossil fuel ‘oil’ and the added advantage of nearly zero pollution, ‘Hydrogen’ is of strategic significance on the renewable non-conventional energy scenario. Unfortunately, however, the present day methods of hydrogen production are based on fossil fuel based energy input for splitting of water. Apparently long term ‘Hydrogen’ production methods will have to be based on renewable sources of energy. Solar energy is the most attractive option and hydrogen production employing solar energy through the process of photoelectrolysis is thought to be the most viable process for hydrogen production. At present the photoelectrochemical (PEC) process leading to hydrogen production is plagued by materials problem. The semiconducting photoelectrode material should be optimised with respect to three different parameters — the band gap, the flat band potential and the stability. The present paper first reviews the salient features of the ‘photoelectrolysis’ process. The basic characteristics of the PEC process leading to photoelectrolysis employing two important semiconducting photoelectrodes namely n-TiO₂ and n-WSe₂ have been described in some detail. New results encountered with these materials have been highlighted. The importance of these results in regard to ‘Hydrogen’ production through ‘photoelectrolysis’ have been outlined.