Effect of preparation by ultrasound-assisted impregnation on properties of CuO/CeO_2/γ-Al_2O_3 catalysts for catalytic combustion of VOCs
CuO/CeO_2/γ-Al_2O_3 catalysts were prepared by both an ultrasound-assisted impregnation method and by a conventional impregnation method. The catalytic combustion of two volatile organic compounds (VOCs), toluene and benzene, was carried out by using these CuO/CeO_2/γ-Al_2O_3 catalysts. The surface properties of these catalysts were characterized with X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The experimental results showed that the ignition temperature and total conversion temperature of the VOCs on the CuO/CeO_2/γ-Al_2O_3 catalysts prepared by ultrasound-assisted impregnation were much lower than those on the CuO/CeO_2/γ-Al_2O_3 catalysts prepared by conventional impregnation, and the activity of the CuO/CeO_2/γ-Al_2O_3 catalysts prepared by ultrasound-assisted impregnation was much higher than that of the CuO/CeO_2/γ-Al_2O_3 catalysts prepared by conventional impregnation. XRD results showed that the use of ultrasound improved the dispersion of Cu ions on the surface of the CuO/CeO_2/γ-Al_2O_3 catalysts.XPS results indicated that the use of ultrasound promoted the distribution of active components on the surface of the CuO/CeO_2/γ-Al_2O_3 catalysts and increased the Cu+ content on the surface of the catalysts so that the activity of the catalysts for VOCs combustion can be enhanced.