Preferential oxidation of CO in H_2-rich feeds over mesoporous copper manganese oxides synthesized by a redox method

摘要

Mesoporous copper manganese oxides with high surface areas (>268 m~2/g) were prepared using the redox method and tested in the preferential oxidation of CO. These materials were highly active and selective under typical operating conditions of a proton-exchange membrane fuel cell. The synthesized catalysts preferentially oxidized CO with a stoichio-metric amount of oxygen in the feed gas. The presence of CO_2 and H_2O in the feed gas retarded catalytic activity significantly at low (<90 ℃) temperatures. The catalysts showed stable activity in long-term (12 h) experiments with realistic feeds. The high catalytic activity was attributed to a combination of factors, including high surface area, low crys-tallinity, low activation energy for CO oxidation, compositional homogeneity of the copper manganese oxides, and the presence of readily available lattice oxygen for CO oxidation. The high selectivity (100% with stoichiometric reactants) was ascribed to the lower activation energy for CO oxidation compared to the activation energy for H_2 oxidation.