Copper and chromium oxide nanocomposite catalysts for simultaneous elimination of CO and oxygenate VOCs in toxic gas emissions

Abstract

Copper and chromium oxide nanocomposite materials with different Cu/Cr ratios were prepared by impregnation of a conventional silica support with toluene solutions of the corresponding acetylacetonate precursors and characterized by X-ray diffraction, Fourier transform infrared spectroscopy, UV–vis spectroscopy, X-ray photoelectron spectroscopy, and temperature-programmed reduction–thermogravimetric methods. Their catalytic behaviour in the total oxidation of CO and different oxygenate VOCs (methanol, dimethyl ether, and ethyl acetate) was tested. The relation between the phase composition and catalytic properties of the materials was also analyzed. It was established that materials with a 1:2 CuO/Cr2O3 molar ratio exhibit high catalytic activity for dimethyl ether oxidation, those with 2:1 and 1:1 ratios are suitable for CO and methanol oxidation, respectively, and both of the latter, but at much higher temperatures, are good for ethyl acetate elimination. A catalyst with an optimal composition of 1:1 (mol/mol) CuO/Cr2O3, working in a reactor with three temperature zones of 490–500 K, 570–580 K, and 620–630 K, is proposed for the effective simultaneous elimination of CO, methanol, ethyl acetate, and dimethyl ether in toxic emissions.