Palladium particles supported on porous CeMnO3 perovskite for catalytic oxidation of benzene

Abstract

Since the traditional palladium based catalysts are susceptible to poisoning and deactivation, and they are expensive, which limits their practical application. The VOCs (volatile organic compounds) emissions are controlled by developing catalysts with low temperature activity and economical practicality. In this paper, the sol-gel method is combined to the impregnation method to synthesize Pd-CeMnO3 perovskite type catalyst. Pd-CeMnO3 (Pd %wt=0.5%wt) shows the T50% = 139 ℃ (the corresponding temperature required when the conversion rate reaches 50%) and T100% = 200 ℃ of removal rate, T50% = 162.5 ℃, and T100% = 220 ℃ of mineralization rate. According to XRD, XPS, H2-TPR, GC-MS and other characterization methods. Its activity benefits from the high dispersion of a certain amount of Pd on the surface of perovskite and the interaction with Ce particles accelerates the transfer of oxygen. The electron transfer of different Pd and Ce ions is beneficial to the generation of active oxygen, which activates the benzene ring into hydrocarbons while adsorbing oxygen to participate in the reaction. A series of heterogeneous reactions occurred and intermediate products such as benzaldehyde, benzaldehyde and phthalic anhydride were detected. Eventually it is oxidized to CO2 and H2O complying with the Mars-van-Krevelen mechanism.