Enhanced visible-light driven photocatalytic mineralization of indoor toluene via a BiVO4/reduced graphene oxide/Bi2O3 all-solid-state Z-scheme system

To improve the photocatalytic mineralization efficiency of indoor toluene under visible light irradiation, an all-solid-state Z-scheme based on the photocatalyst of BiVO4/reduced graphene oxide/Bi2O3 was developed. High-resolution transmission electron microscopy (HRTEM) clearly revealed that reduced graphene oxide (RGO) was anchored between BiVO4 and Bi2O3 particles. The red-shift in the UV-vis diffuse reflectance spectra (DRS) implied the adequate amount of visible light harvesting of the particles. Photocurrent density vs. time and Tafel curves indicated the high electron mobility of the particles. Electronchemical impedance spectroscopy (EIS) measurement implied the increased charge separation efficiency of the particles. The larger specific surface area indicated that full contact occurred between the photocatalyst and the pollutant. As a result, the BiVO4/RGO/Bi2O3 Z-scheme photocatalyst exhibited improved photocatalytic activity, with a mineralization rate that reached up to 95.6%. Electron spin resonance (ESR) proved that the photoinduced radical species ((OH)-O-center dot and O-2(-center dot)) were involved for photocatalytic mineralization of toluene. This work represents a new method to design an all-solid-state Z-scheme photocatalyst with enhanced visible-light driven photoactivity toward indoor air pollutants purification. (C) 2015 Elsevier B.V. All rights reserved.