Catalytic combustion of methane over cobalt doped lanthanum stannate pyrochlore oxide

摘要

A series of La2CoxSn2-xO7-delta oxides with pyrochlore structure have been synthesized by the co-precipitation method as high-temperature catalysts for methane combustion. The dopant strongly influences the thermal stability and redox properties of these pyrochlores. IR measurements show that the Sn-O bond strength was weakened with increasing amount of Co doped in the La2Sn2O7, thus promoting the formation of oxygen vacancy. The reduction rates and the amount of oxygen vacancy would significantly affect catalytic activities of La2CoxSn2-xO7-delta in CH4 oxidation. Among the doped pyrochlores, La2Co0.3Sn1.7O7-delta and La2Co0.5Sn1.5O7-delta possessed optimum activities for methane combustion at low and high temperature, respectively. (c) 2007 Elsevier B.V. All rights reserved.