Tuning oxygen vacancy in Bi2WO6 by heteroatom doping for enhanced photooxidation-reduction properties

The red blood cell-like S,F-codoped Bi2WO6 with suitable oxygen vacancies was synthesized via the hydrothermal-calcination and post-sulfurization, which showed the highest photocatalytic performance in Cr(VI) reduction (94.3% in 120 min) and MO degradation (95.4% in 120 min) under visible-light. [Display omitted] •3D red blood cell-like S,F-codoped Bi2WO6 with suitable oxygen vacancies synthesized by adjusting S/F ratio during post-sulfurization.•The S/F heteroatom codoping could effectively modulate the electronic structure of Bi2WO6 by inducing oxygen vacancy.•Electronic band structure photoelectric and photocatalytic properties were strongly related to oxygen vacancy amount.•The optimal S,F-codoped Bi2WO6 showed the excellent photooxidation-reduction activity under visible-light due to suitable oxygen vacancies in Bi2WO6 crystal lattice. Heteroatom doping was recently regarded as an effective method to tune the band gap and improve the separation and transfer of photogenerated electron-hole pairs in semiconductor photocatalysts. Herein, a novel S,F-codoped Bi2WO6 (S,F-Bi2WO6) with suitable oxygen vacancies was synthesized via the hydrothermal-calcination and post-sulfurization, for efficient Cr(VI) reduction and methyl orange (MO) degradation under visible light. The amount of surface oxygen vacancies could be controlled by adjusting the S/F ratio during the doping process, which modulated the band structure and photogenerated charge behavior of Bi2WO6. The optimal S0.10F-Bi2WO6 exhibited an excellent photooxidation-reduction performance, which Cr(VI) reduction and MO degradation efficiencies were 1.6 and 2.6 times than those of the pristine Bi2WO6 without oxygen vacancy under visible-light, respectively. The enhanced photooxidation-reduction performance was because the right amount of oxygen vacancies could effectively narrow the bandgap and improve the separation efficiency of electron-hole pairs. Thus, this work offered a mild and simply approach for preparing heteroatom doped Bi2WO6 and a potential to be extended to the synthesis of other doped materials for environmental remediation.