Activation mechanisms of silver toward CO oxidation by tungsten carbide substrate: A density functional theory study

The development of efficient catalysts for low temperature CO oxidation is important to the application of fuel cells. In this work, we report that the Ag monolayer on WC (0001) surface (AgML/WC) could effectively catalyze CO oxidation through the L-H mechanism (CO + O-2 -> OOCO -> CO2 + O). The most sluggish reaction step is suggested to be CO + O -> CO2 with a barrier of 0.48 eV, which is 1.21 eV lower than the barrier of O-2 dissociation. The electronic structure and d-band center analyses demonstrate that the promoted activity may originate from the synergistic effect between Ag monolayer and WC. The present study is conducive to design new efficient and cost-effective catalysts for CO oxidation without using of the noble platinum. (C) 2019 Elsevier B.V. All rights reserved.