Novel visible-light sensitive vanadate photocatalysts for water oxidation: implications from density functional theory calculations

Abstract

Two vanadates, Ag₂Sr(VO₃)₄ and Sr(VO₃)₂, have been studied as visible-light-driven water oxidation photocatalysts with the help of density-functional theory calculations. Our computational results for the density of states and partial charge densities implied that Ag₂Sr(VO₃)₄ and Sr(VO₃)₂ possess desirable electronic structures for the water oxidation reaction, i.e., the valence band (VB) maximum of Ag₂Sr(VO₃)₄ consists of multiple orbitals of Ag d and O p, while Sr(VO₃)₂ has a broad VB associated with oxygen non-bonding states. We have experimentally demonstrated that these vanadates efficiently oxidize water to O₂ under irradiation of visible light in the presence of the sacrificial agent.