Solid–Liquid Crystal-Growth Control of Faceted BiVO4 Photocatalysts for Enhanced Solar H2O2 Production and O2 Evolution

Faceted monoclinic BiVO₄ is a representative visible-light-responsive photocatalyst for water oxidation and solar H₂O₂ production, but its performance strongly depends on crystal morphology, defect density, and charge transport. Here, we optimized the solid–liquid synthesis of faceted BiVO₄ particles from layered K₃V₅O₁₄ and Bi(NO₃)₃ by controlling Mo doping and key reaction parameters. The optimized synthesis promoted the formation of highly crystalline faceted BiVO₄ particles with suppressed defect-related absorption. Time-resolved imaging analysis revealed that the optimized particles contained a larger fraction of active regions, where photogenerated electrons and holes exhibited 3–5 times longer lifetimes. Consequently, the optimized BiVO₄ photocatalyst showed 1.4-fold higher H₂O₂ generation activity from pure water and a 1.2-fold higher O₂ evolution activity in AgNO₃ solution than the reference sample. These results demonstrate that solid–liquid crystal-growth control is an effective strategy for improving faceted BiVO₄ photocatalysts for artificial photosynthesis.