Solid state reaction between BiOI and NH₄VO₃ allows to synthesize BiVO₄ with precise chemical composition. The resultant stoichiometric BiVO₄ shows attractive photocatalytic activity and superior stability to nonstoichiometric analogous.

BiVO₄ is a promising photocatalyst for driving the solar water splitting. In this work, the report on a new strategy to synthesize BiVO₄ by employing the solid-state chemical reaction between BiOI and NH₄VO₃ precursors. Reaction conditions, for example, reaction time, molar ratio of precursors are varied to investigate its impacts on the morphology and chemical composition of the resultant BiVO₄. Impacts of the chemical composition on the photocatalytic activity and stability of BiVO₄ are also investigated. It is demonstrated that the stoichiometric BiVO₄ displayed the best stability, meaning the highest resistance again the corrosion while Bi₂O₃ impurity is detrimental to the operation of BiVO₄ causing an acceleration of corrosion and lowering of photocatalytic activity. In contrast, the critical role of V₂O₅ impurity is evidenced in protecting BiVO₄ against the corrosion and enhancing its photocatalytic activity.