CuO/CeO2/γ-Al2O3 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/CeO2/γ-Al2O3 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/CeO2/γ-Al2O3 catalysts prepared by ultrasound-assisted impregnation were much lower than those on the CuO/CeO2/γ-Al2O3 catalysts prepared by conventional impregnation, and the activity of the CuO/CeO2/γ-Al2O3 catalysts prepared by ultrasound-assisted impregnation was much higher than that of the CuO/CeO2/γ-Al2O3 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/CeO2/γ-Al2O3 catalysts.XPS results indicated that the use of ultrasound promoted the distribution of active components on the surface of the CuO/CeO2/γ-Al2O3 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.
The adsorption isotherms of four activated carbons (Norit RB1, Chemviron BPL, Monolit, and Ambersorb-572) have been examined by nitrogen adsorption at 77.5 K. A method for adsorption potential distribution calculation has been proposed based on the adsorption isotherms. This distribution provides information about possible changes in the Gibbs free energy caused by the energetic and geometrical heterogeneities of an activated carbon as well as by the adsorbate-related entropic effects. The general character of the adsorption potential distribution is clearly visible by its simple relation to the micropore and mesopore distribution.
CuOγ-Al2O3 catalysts were prepared by plasma treatment and conventional impregnation methods. The catalytic combustion of two kinds of volatile organic compounds (VOCs), toluene and benzene, were carried out over these CuOγ-Al2O3 catalysts. The surface properties of these catalysts were characterized by X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The experimental results showed that in catalytic combustion the activity of the CuOγ-Al2O3 catalyst prepared via plasma was much higher than that of the CuOγ-Al2O3 catalyst prepared by conventional impregnation method. XRD results showed that an enhanced dispersion had been achieved with the plasma treatment. SEM results indicated that the size became much smaller and the surface became more uniform with the plasma treatment.
