Promoting Effect of Ce in Ce/OMS-2 Catalyst for Catalytic Combustion of Dimethyl Ether

Abstract

A new route to synthesize efficient Ce-doped manganese oxide octahedral molecular sieves (OMS-2) catalysts using birnessite precursor was developed. Their catalytic activities in the combustion of dimethyl ether (DME) were evaluated. N2 adsorption, XRD, H2-TPR, O2-TPD and XPS techniques were employed in the catalyst characterization. A promoting effect of Ce in the Ce/OMS-2 catalysts on the catalytic activity was observed. For the most active sample with a Ce/Mn ratio of 0.07 (starting Ce/Mn molar ratio, Ce-7/OMS-2), the light-off temperature (the temperature acquired for 10% DME conversion, T 10) and full-conversion temperature (the temperature acquired for 90% DME conversion, T 90) were 149 and 159 °C, respectively. The catalytic activity of Ce-7/OMS-2 was stable up to 50 h. Ce-7/OMS-2 is a promising catalyst for DME catalytic combustion. The mobility of the active lattice oxygen, the larger amount and the more facile supply of the lattice oxygen species on the surface of Ce/OMS-2 are of crucial importance for the reaction. Ce-doped manganese oxide octahedral molecular sieves (OMS-2) catalysts were synthesized and the catalytic activities for the combustion of dimethyl ether (DME) are investigated. Introduction of Ce into OMS-2 greatly promoted the catalytic activity. For the most active sample with a Ce/Mn ratio of 0.07 (starting Ce/Mn molar ratio), the light-off temperature (temperature at 10% conversion, T 10) and full-conversion temperature (temperature at 90% conversion, T 90) were 149 and 159 °C, respectively.