Bi0 and oxygen vacancies co-induced enhanced visible-light photocatalytic detoxication of three typical contaminants over Bi2WO6 treated by NaBH4 solution

Abstract

In this work, the photocatalytic performance of bismuth tungstate (Bi2WO6) was notably improved through the synergism of oxygen vacancies (OVs) and surface plasmon resonance (SPR) effect of Bi0. After treated with NaBH4 solution, the content of OVs and Bi0 on the surface of Bi2WO6 can be regulated. The effects of the NaBH4 solution treatment on visible-light photocatalytic performance of Bi2WO6-based photocatalysts on the degradation of rhodamine B (RhB), tetracycline (TC) and phenol (PhOH) were indagated. The highest photocatalytic performance was obtained for BWO-100. The degradation reaction rate constant of RhB, TC and PhOH on BWO-100 is 2.3, 1.65 and 2.1 times of that over the fresh Bi2WO6, respectively. Introduction of richer OVs and relative lower content of metal Bi0 endows Bi2WO6 with highly efficient separation of photogenerated carriers, which leads to increased superoxide radicals (•O2−), hydroxyl radicals (•OH), and the experimental results have proven that they are the main active substances that mineralize above three typical organic pollutants. This demonstration provides a reference for design highly efficient photocatalysts by a mild strategy.