Chinese Journal of Catalysis

Chinese Journal of Catalysis ›› 2013, Vol. 34 ›› Issue (5): 923-931.DOI: 10.1016/S1872-2067(12)60556-7

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Deactivation mechanism of PdCl2-CuCl2/Al2O3 catalysts for CO oxidation at low temperatures

FENG Yafen, WANG Li, ZHANG Yanhui, GUO Yun, GUO Yanglong, LU Guanzhong   

  1. Research Institute of Industrial Catalysis, East China University of Science and Technology, Shanghai 200237, China
  • Received:2013-01-21 Revised:2013-05-20 Online:2013-05-06 Published:2013-05-06
  • Supported by:

    This work was supported by the Key Project of Research Program of China (2013CB933201), the National Basic Research Program of China (2010CB732300), The New Century Excellent Talents in University (NCET-10-0377), and the Fundamental Research Funds for the Central Universities (222201013003).

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Abstract:

Supported Wacker catalysts exhibited high activity for low temperature CO oxidation, but high concentrations of water in the reaction gas could lead to the deactivation of the catalyst. The PdCl2-CuCl2/Al2O3 catalysts were prepared, and a high relative humidity deactivation mechanism was suggested after characterizing the fresh and spent catalyst by X-ray diffraction, N2 absorption-desorption, X-ray photoelectron spectroscopy, H2-temperature programmed reduction and in situ diffuse reflectance infrared Fourier transform spectroscopy. The results showed that the water could adsorb and condense on the surface of the catalyst, which arouses the aggregation and transfer of Cu species into the internal pores of the catalyst. This weakens the interactions between the Pd and Cu species and reduces the re-oxidation ability of Pd0 to Pd2+, which blocks redox cycling and results in the decrease of CO oxidation activity.

Key words: Low-temperature CO oxidation, Palladium chloride, Copper chloride, Aluminum oxide, Deactivation