Enhanced photocatalytic oxidizing ability via adjusting the band-edge position and oxygen defect concentration of bismuth phosphate

Abstract

Abstract Oxide defect engineering exert huge impact on semiconductor photocatalysis, which not only can adjust the band-gap structure but also can act as electron trap for photoinduced carriers separation. In this work, the photoactivity oxidation capability of bismuth phosphate were enhanced by the fine-tuning of lattice parameters with different oxygen defect concentrations. The non-linear changes of lattice parameters calculated from XRD suggested that the lattice oxygen missed during thermal treatment. XPS, Raman, EPR, HRTEM, PL and UV–vis diffuse reflectance spectroscopy also identified that the types and concentrations of defect changed with various temperatures. The photo-carriers separation efficiency and oxidizability are increased via controllable defect density to adjusting lattice parameters that can attract photogenerated electrons and lower valance band position, respectively. Benefiting from the higher separation efficiency of photogenerated carriers and stronger oxidation capability, the BiPO4 with the smallest lattice parameter exhibited reinforced photocatalytic removal efficiency of methylene blue, better repeatability and stability, which is 3.2 times as high as that of pristine BiPO4. The findings, controlling oxygen vacancy concentration to regulate the lattice parameters, could be a promising strategy for enhancing photoactivity oxidizing ability of photocatalysts.