Enhanced photocatalytic destruction of pollutants by surface W vacancies in VW-Bi2WO6 under visible light

W vacancies containing Bi2WO6 (VW-Bi2WO6) was synthesized by a reductant-involved hydrothermal process. The photoactivity of Bi2WO6 was enhanced by 3.3 times and the TOC removal rate increased from 38.3% to 64.7% after the introduction of surface W vacancies. Positron annihilation spectrometry (PAS), XPS, Raman spectra and other characterization results indicated that W vacancies existed on the catalyst surface. The surface W vacancies were proved to widen the band gap and negatively shift CB edge to produce more O2•- and photoexcited holes at catalyst surface, as confirmed by ESR and radicals trapping experiments. Further, according to the results of pyridine adsorbed FTIR and Zeta potentials, the enhanced interaction between pollutants and VW-Bi2WO6 was confirmed. As a result, the active species produced at surface were able to be accelerated to directly react with organic pollutants, leading to the highly efficient degradation and mineralization of pollutants in water.