Improved O2 evolution from a water splitting reaction over Er3+ and Y3+ co-doped tetragonal BiVO4

Abstract

Erbium–yttrium co-doped BiVO₄ with a tetragonal structure is synthesized by means of a surfactant free hydrothermal method. The studied photocatalyst shows good photoactivity under sun-like excitation for the degradation of methylene blue (MB) and for O₂ evolution. From structural and morphological characterization, it has been stated that the presence of lanthanides induces the stabilization of the tetragonal phase. This is probably due to the substitutional occupation that occurs in the BiVO₄ lattice. The photocatalytic performance under visible-NIR radiation clearly evidences the occurrence of an up-conversion process involved in the overall photo-electronic mechanism. The tetragonal phase Er_0.0075,Y_0.03–Bi_0.9625VO₄ system gives the highest O₂ evolution rate (425 μmol g⁻¹ h⁻¹) under sun-like excitation, being 8 times higher than that attained for m-BiVO₄ (53 μmol g⁻¹ h⁻¹).