Enhanced photocatalytic detoxification performance of OVs-enriched Co3O4/BiVO4 benefited from S-scheme interfacial charge pairs separation mechanism

Photocatalysts possess great application prospects in the environmental and energy field, and heterojunction photocatalysts can optimize the separation and transfer of photoinduced carriers to achieve high performance photocatalysis. Herein, Co3O4/BiVO4 (CoBVO) heterojunction photocatalysts were prepared in-situ using a one-step hydrothermal method. The impact of heterojunction structure and oxygen vacancies (OVs) on the light absorption range, band structure, and photogenerated carriers separation behavior of BiVO4 were studied by characterizing the photoelectric properties of the material. The results indicate that the concentration of OVs on BiVO4 samples changes due to formation of heterojunctions. Under simulated solar light irradiation, photocatalytic performance of the synthesized catalysts was investigated using Cr(VI) and moxifloxacin as simulated contaminants, photocatalytic reduction rate constant of Cr(VI) on 2CoBVO (molar ratio of Co/Bi is 2%) is 4.4 times of that on the single BiVO4, and the photocatalytic degradation rate constant of moxifloxacin on 2CoBVO is 1.6 times of that on the reference BiVO4. S-scheme interfacial charges separation and enhanced photocatalytic performance mechanism of OVs-enriched Co3O4/BiVO4 heterojunctions were elucidated based on the experimental observations. This work provides ideas for one-step synthesis of bismuth-based composite photocatalysts, which can be applied to the photocatalytic treatment of heavy metals and antibiotics.