Deep oxidation of chlorinated VOCs over CeO2-based transition metal mixed oxide catalysts

Cerium-transition metal mixed oxides (4Ce1M, M = V, Cr, Mn, Fe, Co, Ni and Cu) were prepared by coprecipitation method and investigated for deep oxidation of four chlorinated VOCs with quite different molecule structures. 4Cel M catalysts show mesoporous structures with larger specific surface area and pore volume, and some metal ions can go into the lattice of fluorite, which contributes to improving the stability of the active components. The redox properties of 4Ce1M catalysts are significantly promoted due to the strong interaction between CeO2 and MOx, which facilitates the destruction of the reactants and byproducts at lower temperature in the process of CVOCs oxidation. Especially, 4Cel Cr catalyst exhibits the best catalytic activity and selectivity, mainly due to the formation of Cr6+ species with strong oxidizing ability. 4Cel Cr also represents good durability for DCE destruction during the 100 h continuous test, and the chemical adsorbed Cl species on the surface can be removed above 325 degrees C. Moreover, the presence of water or non-chlorinated VOCs can slightly decrease the conversion of chlorinated VOCs at lower temperature due to the competitive adsorption for active sites, while promote at higher temperature (above 300 degrees C) because of the contribution to removing Cl species away from the surface. (C) 2014 Elsevier B.V. All rights reserved.