ABSTRACT
This chapter focuses on solar photocatalytic water splitting. Water splitting is referred to as the chemical reaction that splits water into its constituents, that is, hydrogen and oxygen. Splitting of water on a submicron-sized semiconductor photocatalyst can be imagined to occur in three steps. The steps are photon-energy more than the bandgap energy of the semiconductor is absorbed on the surface of it and the photo-excited electron–hole pairs are generated, the carriers migrate to the surface without recombination, and absorbed species are reduced and oxidized. The rate of water splitting using an optimally modified photocatalyst was proportional to light intensity under solar equivalent or weaker irradiation, thus indicating that the accumulation of photoexcited electrons and holes was negligible. Solar water splitting employs semiconductor photocatalysis with solar energy for production of hydrogen and oxygen from water. Water electrolysis can be accomplished by photovoltaic cells, wind turbines, solar thermochemical, photoelectrochemical, biomass production, or photocatalytic hydrogen production.
