Boosting the quantum efficiency of the BiVO4 photoanode by increasing the oxygen vacancies for highly-efficient solar water oxidation

Abstract

BiVO₄ (BVO) is a promising photoanode material for photoelectrochemical (PEC) water splitting. However, it is severely restricted by its short charge diffusion length and poor charge transport. Introducing oxygen vacancies into BVO is an effective method to solve these problems because they serve as surface electron capture sites and facilitate charge separation. In this work, a novel gas reaction method using chemical vapor deposition was used to produce abundant oxygen vacancies in single-crystal BVO. Oxygen vacancies in BVO acted as hole donors. This method effectively reduced the surface agglomeration and produced uniform BVO crystals. The optimized BVO photoanode achieved a photocurrent density of 2.44 mA cm⁻² (1.23 V vs. RHE) and an incident photon-to-current efficiency of 90% (450 nm). This work provides an effective strategy to prepare high-performance BVO photoanodes by chemical vapor deposition, electrodeposition and thermal evaporation.