Oxygen vacancy regulation in Nb-doped Bi2WO6 for enhanced visible light photocatalytic activity

Novel Nb-doped Bi2WO6 nanosheets have been successfully synthesized by a simple hydrothermal method. XRD, Raman spectra, XPS and SEM were adopted to analyze the structure and morphology of the samples, then the structure-dependent optical properties, photoelectric behavior and photocatalytic activities were investigated, and the structure–property relationship was also discussed. The results show that doping Nb5+ can increase the oxygen vacancies in the Bi2WO6 lattice and reduce the optical band gap of Bi2WO6. The oxygen vacancies also act as electron traps, which promote the separation of photogenerated carriers. Hence, compared with the pure Bi2WO6, the as-prepared Nb-doped Bi2WO6 nanosheets exhibit enhanced visible-light photocatalytic activity for removing contaminants in water such as rhodamine B and tetracycline.