Photoelectrochemical oxidation of water and degradation of pollutants using simple Bi-based metal oxide semiconductors under visible light irradiation

Abstract Heterogeneous photocatalytic water oxidation is a promising system for sustainable and competitive solar fuel production since 1972, discovered by Fujishima and Honda using TiO2 semiconductor (SC). Despite the good stability issue of the TiO2 material, it can separate the charge carriers only under UV light from the valence band (VB) to the conduction band due to high bandgap energy. Visible light–active n-type Bi-based metal oxides are considered as stable, efficient SCs to oxidize water and degrade pollutants because of the favorable band energy positions: particularly the VB energy as well as visible light activity of the material. These metal oxides are of low production cost, less toxicity, and easily soluble with other elements, resulting in a large family of solid solution compounds. In this chapter, the synthesis and characteristics of Bi-based simple oxides obtained through various routes for different photoelectrochemical applications is being explored. Effects of different synthetic routes, structure, surface morphology, modifying agents, etc. on their performance are being discussed in detail.