Chinese Journal of Catalysis ›› 2016, Vol. 37 ›› Issue (1): 193-198.DOI: 10.1016/S1872-2067(15)60969-X

• Articles • Previous Articles    

Theoretical studies of CO oxidation with lattice oxygen on Co3O4 surfaces

Yang-Gang Wanga, Xiao-Feng Yangb, Jun Lia   

  1. a Department of Chemistry & Key Laboratory of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Tsinghua University, Beijing 100084, China;
    b State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, China
  • Received:2015-08-07 Revised:2015-09-06 Online:2015-12-26 Published:2015-12-26
  • Supported by:

    This work was supported by the National Basic Research Program of China (2011CB932401) and the National Natural Science Foundation of China (21221062).

Abstract:

Low-temperature CO oxidation has attracted extensive interest in heterogeneous catalysis because of the potential applications in fuel cells, air cleaning, and automotive emission reduction. In the present study, theoretical investigations have been performed using density functional theory to elucidate the crystal plane effect and structure sensitivity of Co3O4 nano-catalysts toward catalyzing CO oxidation. It is shown that the surface Co-O ion pairs are the active site for CO oxidation on the Co3O4 surface. Because of stronger CO adsorption and easier removal of lattice oxygen ions, the Co3O4(011) surface is shown to be more reactive for CO oxidation than the Co3O4(001) surface, which is consistent with previous experimental results. By comparing the reaction pathways at different sites on each surface, we have further elucidated the nature of the crystal plane effect on Co3O4 surfaces and attributed the reactivity to the surface reducibility. Our results suggest that CO oxidation catalyzed by Co3O4 nanocrystals has a strong crystal plane effect and structure sensitivity. Lowering the vacancy formation energy of the oxide surface is key for high CO oxidation reactivity.

Key words: Carbon monoxide oxidation, Cobalt oxide, Crystal plane effect, Ion-pair active center