Abstract
The CO catalytic oxidation at ambient temperature and high space velocity was studied over the Pd\bond Cu/MOx (MOx=TiO2 and Al2O3) catalysts. The higher Brunauer–Emmett–Teller area surface of the Al2O3 support facilitates the dispersion of Pd2+ species, and the presence of Cu2Cl(OH)3 accelerates the re-oxidation of Pd0 to Pd2+ over the Pd\bond Cu/Al2O3 catalyst, which contributed to better performance of CO catalytic oxidation. The poorer activity of the Pd\bond Cu/TiO2 catalyst was attributed to the lower dispersion of Pd2+ species because of the less surface area and the non-formation of Cu2Cl(OH)3 species. The presence of saturated moisture showed a negative effect on CO conversion over the two catalysts. This might be because of the competitive adsorption, the formation of carbonate species and the transformation of Cu2Cl(OH)3 to inactive CuCl over the Pd‒Cu/Al2O3 catalyst, which facilitates the aggregation of PdO species over the Pd‒Cu/TiO2 catalyst under the moisture condition.
Acknowledgement
This work is also supported by this financial grant (Minhang District Science and Technology Project of Shanghai (grant number: 2012MH017)).