Catalytic oxidation of low-concentration CO at ambient temperature over supported Pd‒Cu catalysts

Abstract

The CO catalytic oxidation at ambient temperature and high space velocity was studied over the Pd\bond Cu/MO_x (MO_x=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.

Keywords:

• CO oxidation
• low concentration
• ambient temperature
• Pd‒Cu catalyst
• deactivation

Acknowledgement

This work is also supported by this financial grant (Minhang District Science and Technology Project of Shanghai (grant number: 2012MH017)).