Catalytic combustion of volatile organic compounds over CuO-CeO2 supported on SiO2-Al2O3 modified glass-fiber honeycomb

Abstract

CuO-CeO2 monolithic catalysts supported on SiO2-Al2O3 modified glass-fiber honeycomb were prepared via co-impregnation method and their performance in the oxidation of volatile organic compounds (VOCs) such as ethyl acetate, isopropanol and toluene was evaluated. Various techniques such as N2 sorption, X-ray powder diffraction (XRD), hydrogen-temperature programmed reduction (H2-TPR), ammonia-temperature programmed desorption (NH3-TPD) and chemisorption of VOCs were employed to characterize the catalysts. The results show that the copper oxide species are highly dispersed on the CuO-CeO2 based catalysts; moreover, the size of CeO2 nanoparticles increases with the decrease of copper/ceria molar ratio. The addition of ceria oxide can evidently increase the amount of total acid sites, especially the Lewis ones, which can then enhance the adsorption capacity of ethyl acetate and isopropanaol and promote the oxidation of ethyl acetate and isopropanaol. In the case of toluene combustion, the addition of large amount of CeO2 may decrease the reducibility and oxygen activation capability; as a result, it contributes little to the adsorption of toluene, resulting in a low activity in the oxidation of toluene. The catalytic activity is related both to the reactivity of surface oxygen and to the adsorption capacity of the catalyst towards VOC molecules, which are determined by the complex interactions among copper, cerium oxide and the support.