Rich oxygen vacancies facilitated visible light-driven removal of phenol and Cr(VI) over Bi2WO6 decorated by sorghum straw carbon

Abstract

Surface features of photocatalyst perform a significant action in influencing photocatalytic properties by affecting the separation of photoactivated carriers. Surface modification is considered as a robust approach to facilitate the separation of photoactivated carriers. In this presentation, sorghum straw carbon (SSC) treated in NH3 atmosphere was employed to surface modification of Bi2WO6 photocatalyst prepared by a hydrothermal method. The composition, optical absorption and photogenerated carrier separation of the photocatalysts were investigated through various characterization methods. Compared with the pure Bi2WO6, N-containing sorghum straw carbon (N-SSC)/Bi2WO6 composite photocatalysts have higher surface hydroxyl, oxygen defects and photogenerated e-/h+ pairs separation ability. When the mass ratio of N-SSC/Bi2WO6 is 1.5%, the sample manifests excellent visible light activity. The photocatalytic decontamination rate constant of phenol on the 1.5% N-SSC/Bi2WO6 is 8-fold of that on the single Bi2WO6. The photocatalytic reduction efficiency for Cr (VI) on the 1.5% sample is 37.8% after 120 min under visible light photocatalysis, and the photocatalytic reduction rate constant of Cr (VI) over the 1.5% sample is 1.8-fold of that on the neat Bi2WO6. The active species were analyzed, and then the photocatalytic mechanism was interpreted.