Band Engineering of Photocatalytic BiVO4 with Modified Vanadium States via Potassium Chloride Addition during Hydro-Thermal Synthesis and Post-Annealing

The monoclinic BiVO4 in a powder state was prepared via hydrothermal method, with the addition of KCl as structure-directing agent. as-prepared sample calcined at different temperatures (400–600 °C), either air or Ar gas. It is found that, though morphology and crystal structure mostly remain unchanged, bandgap properties are modified during calcination. A detailed analysis surface chemical states optical absorption reveals involvement tetravalent vanadium ions oxygen vacancies cause band modification. to be tunable changing calcination condition, well concentration precursor. photocatalytic samples greatly enhanced precursor, but degraded by post-annealing, where residual Cl may act an inhibitor. photoactivity explained terms favorable faceting, modification, heterojunction BiVO4/BiOCl.