Vacancy-engineered bismuth vanadate for photoelectrocatalytic glycerol oxidation with simultaneous hydrogen production

Abstract

Photoelectrocatalytic (PEC) water splitting offers a sustainable pathway for clean H₂ production, and its integration with biomass valorization further enhances eco-economic efficiency. In this study, a BiVO₄ catalyst with an optimized oxygen vacancy (Ov-BVO) concentration was grown on a SnO₂ skeleton, achieving efficient PEC glycerol oxidation to selectively produce dihydroxyacetone (DHA) and H₂ under neutral conditions. By incorporating Ov-BVO with SnO₂, the light-harvesting and photo-induced carrier transfer efficiencies were significantly improved. Ov played a crucial role in selectively absorbing and activating the secondary –OH group of glycerol molecules, as revealed by theoretical and experimental studies. However, excessive Ov induced carrier recombination, underscoring the need for an optimal Ov concentration, which was achieved by tailoring heat treatment conditions. The SnO₂/BVO-400 catalyst demonstrated a trade-off between the prolonged carrier lifetime and efficient reactant adsorption, exhibiting a PEC DHA productivity of 144 mmol m⁻² h⁻¹ with 26.5% selectivity, alongside H₂ generation (1850 mmol m⁻² h⁻¹). This work lays the groundwork to achieve value-added chemical fabrication through neutral PEC glycerol reforming and the potential scale-up of this sustainable technology.