Photocatalytic degradation of gaseous benzene with Bi2WO6/Palygorskite composite catalyst

Abstract

Bismuth tungstate/palygorskite (Bi2WO6/Pa) composite photocatalyst was prepared by hydrothermal method and characterized by X-ray diffraction (XRD), Fourier transform-infrared (FT-IR), scanning electron microscope (SEM), transmitting electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), nitrogen adsorption-desorption measurement (BET), UV–Vis reflection spectrometer (DRS) and photoluminescence (PL). The effects of composite catalysts with different preparation conditions on the degradation of benzene were discussed. The results showed that the composite catalyst had excellent catalytic performance on gaseous benzene degradation. When benzene initial concentration was 50 mg/m3, over Bi2WO6/palygorskite with mass ratio was 8:2, calcined temperature was 250 °C and the precursor pH value was 3, the benzene degradation efficiency reached 68.2% and the mineralization efficiency reached 62.7% after 120 min 365 nm UV light irradiation. The high activity and stability of composite catalyst could be attributed to its large specific surface area which improved the condition of photoinduced electron-hole recombination, and electron-hole and superoxide radicals played an important role in the photo-degradation of benzene.