Stabilized oxygen vacancies over heterojunction for highly efficient and exceptionally durable VOCs photocatalytic degradation

In this study, an electrochemical reduction strategy was adopted to introduce oxygen vacancies (OVs) into BiVO4/WO3/TiO2 nanotubes composite film (R-BiVO4/WO3/TNTs), and the newly generated OVs were mainly distributed on BiVO4. Desired concentration and distribution of the OVs were achieved by optimizing the reduction potential and duration. By introducing the reduced BiVO4, the inherent reaction mechanism dominated by OH and photogenerated hole was changed into the reaction dominated by O2− and hole, thereby improving the stability of the OVs in the catalytic process. The construction of heterojunction with the stabilized OVs had a significant contribution towards charge carrier separation and transmission in the material, and especially the stability of the performance. Thus, the R-BiVO4/WO3/TNTs exhibited a 28 times higher photocurrent intensity than the pristine BiVO4/WO3/TNTs, and the one-time purification experiment further confirmed the excellent performance and persistent nature of R-BiVO4/WO3/TNTs composite film in the actual treatment of VOCs.