(504e) Elucidating the Role of Oxygen Coverage in CO2 Reduction on Mo2C

Authors: 
Dixit, M., University of Pittsburgh
Mpourmpakis, G., University of Pittsburgh
Porosoff, M. D., University of Rochester
Peng, X., University of Pittsburgh
Willauer, H. D., Naval Research Laboratory
Molybdenum carbide (Mo2C) is a promising and low-cost catalyst for the conversion of CO2 to CO. However, the underpinning mechanism occurring on the catalyst surface and the surface characteristics of Mo2C catalyst under the reaction conditions are still elusive. In this study, we employ first principles calculations to understand the CO2 dissociation mechanism on β-Mo2C (001) under different oxygen coverage on the catalyst surface (oxycarbide).1, 2 Our results demonstrate that with increasing oxygen coverage, there is an electronic modification on the catalyst surface (e.g. d-band shift on Mo atoms), that in turn, tunes the interactions of the adsorbates and the CO2 dissociation barriers. Interestingly, we reveal linear relationships between the oxygen coverage and electronic modification with the reactivity of the catalyst. We show that CO2 can adsorb and dissociate on the oxygen covered Mo2C surface, even in the presence of surface oxygen up to 0.5 monolayer (ML). Our results rationalize a series of experimental observations.

References:

  1. M. Dixit, X. Peng, M. D. Porosoff, H. D. Willauer and G. Mpourmpakis, Cat. Sci. Tech., 2017, 7, 5521-5529.
  2. M. D. Porosoff, J. W. Baldwin, X. Peng, G. Mpourmpakis and H. D. Willauer, ChemSusChem, 2017, 10, 2408-2415.