Novel photocatalyst of V-based solid solutions for overall water splitting

Abstract

A series of mixed oxide (BYV) photocatalysts Bi_xY_1−xVO₄ were prepared by solid state reaction. When the composition was below x = 0.65, BYV were of single phase and of zircon-type structure and can be regarded as solid solutions of YVO₄ and BiVO₄ within the same structure. All the BYV solid solutions were proved for the first time to be effective photocatalysts based on V with d⁰ electron configuration for overall water splitting under UV light. 0.2 g Bi_0.5Y_0.5VO₄ with cocatalyst showed the highest photocatalytic activity (402 μmol h⁻¹ H₂ and 196 μmol h-1 O₂) among all the samples, about 25 times that of YVO₄. Under visible light irradiation, BYV solid solutions also performed photocatalytic activity to produce H₂ and O₂ from sacrificial reagent solutions. The photocatalytic activity of BYV solid solutions was effectively improved by increasing calcination temperature from 1073 to 1173 K. Band structure calculation by using the WIEN2K code indicated that incorporation of Bi in YVO₄ caused a reduction of the band gap and dispersion of the conduction band of BYV solid solution due to the interaction between Bi6s/6p and VO₄, which was demonstrated to be the major factor for effective activity of BYV solid solutions.