THE EFFECT OF BAND ENGINEERING OF SEMICONDUCTORS ON PHOTOCATALYIC WATER SPLITTING: A REVIEW

Abstract

The direct conversion of solar energy using a photocatalyst in a water splitting reaction is a source of a sustainable and clean hydrogen supply. In general, photocatalysts are semiconductors that possess valence and conduction bands. These energy bands permit the absorption of photon energy to excite electrons in the outer orbitals of the photocatalysts. Photoexcited electron and hole pairs can subsequently induce a watersplitting reaction to produce hydrogen and oxygen. Photocatalytic water splitting is affected by the band level and crystallinity of the photocatalyst. Therefore, band engineering using chemical modifications such as cationic and anionic modification could createa photocatalyst suitable for the large-scale production of hydrogen. In this paper, cationic and anionic modifications of photocatalysts and the effects of these modifications onphotocatalytic water splitting are reviewed.