ABSTRACT
Photoelectrochemical (PEC) cells have been developed to convert solar light energy into fuels like H2 or MeOH, due to the abundance of the required reagents, water and sunlight. Researchers have developed a number of techniques to carry out water splitting by using the photovoltaic (PV) principle. These techniques can be categorized as: coupled PV- electrolysis system, PEC water splitting, and photocatalytic water splitting. PEC and photocatalytic water splitting differ in the fact that PEC takes place on an electrode. Solar conversion of luminescent energy to hydrogen is performed at PEC devices. In order to promote water splitting using photoanodes, the valence band (VB) edge of the n-type semiconductor should be more positive than the oxygen evolution potential in order for the photoanode to oxidize water. Doping is one strategy to improve the conductivity of semiconductors and reduce recombination of the photogenerated electron–hole pairs.
