A comparison study of the Bi2WO6based composite photocatalysts for the degradation of bisphenol A (BPA) under visible-light irradiation

Abstract

ABSTRACT To study the degradation of bisphenol A (BPA) of the different Bi2WO6-based composite photocatalyst under visible-light irradiation, a novel Z-scheme Cu2S/reduced graphene oxide/Bi2WO6 (Cu2S/RGO/Bi2WO6) was successfully synthesised by solvothermal-hydrothermal method, andBi25FeO40/RGO/Bi2WO6 was introduced for comparative study. The Cu2S/RGO/Bi2WO6 was characterised by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS) test and X-ray photoelectron spectrometer (XPS).TheBi2WO6,Cu2S/RGO/Bi2WO6andBi25FeO40/RGO/Bi2WO6 were used to degrade bisphenol (BPA) under visible light, respectively, and in addition peroxymonosulfate (PMS) was used as an additive for the Cu2S/RGO/Bi2WO6 to degrade BPA. For Cu2S/RGO/Bi2WO6@PMS, the removal ratio of BPA is 91.0% in 40 minutes, which is much higher than pure Bi2WO6 (22.0%),Cu2S/RGO/Bi2WO6 without PMS (56.1%) and Bi25FeO40/RGO/Bi2WO6 (48.3%). A Z-scheme photocatalytic mechanism was proposed for Cu2S/RGO/Bi2WO6@PMSbased on the results of UV–vis DRS, PL analysis and Mott–Schottky curve. There are four factors that contribute to CuS2/RGO/Bi2WO6with PMS to achieve excellent photocatalytic performance: 1. The larger specific area; 2. the higher absorption capacity of visible light; 3. RGO can act as a very important role to significantly accelerate electron transfer, and 4. PMS can be activated to generate •SO4 − for BPA degradation.