Photocatalytic degradation of pendimethalin over Cu2O/SnO2/graphene and SnO2/graphene nanocomposite photocatalysts under visible light irradiation

The Cu2O/SnO2/graphene (CSG) and SnO2/graphene (SG) nanocomposite photocatalysts were prepared by simple sal-gel growth method, and characterized by Fourier transform infrared spectra (FTIR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Brunauer-Emmett-Teller (BET) measurements, respectively. The photocatalytic efficiency of catalysts were evaluated by degradation of pendimethalin under visible light irradiation (lambda > 420 nm), which conformed that CSG and SG exhibited better photocatalytic activity than SnO2 or graphene alone. An effort has been made to correlate the photoelectro-chemical behavior of these samples to the rate of photocatalytic degradation of pendimethalin. The results demonstrated that the cuprous oxide addition into SG materials could greatly improve the photoelectric activity. The mechanism of photocatalytic reaction is proposed based on the energy band theory and experimental results. The CSG catalyst with higher photocatalytic activity may have great potential in various fields. (C) 2013 Elsevier B.V. All rights reserved.