Assessing the Role of Surface Carbon on the Surface Stability and Reactivity of ..Beta..-Mo2C Catalysts

Sean Tacey, Matthew Jankousky, Carrie Farberow

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3 Scopus Citations


Transition-metal carbides, e.g., Mo2C, promote industrially important catalytic reactions with activities comparable to precious-metal catalysts. Yet, the nature of the catalytically active sites remains unclear. Herein, density functional theory calculations are applied to systematically assess the stability of low-Miller-index facets of β-Mo2C as a function of carbon chemical potential (μC) and surface-carbon coverage (nC). When reconstruction of surface carbon is considered to characterize β-Mo2C under varying environments, the (1 1 1) and (1 0 1) surfaces are predicted to be most stable, dominating the Wulff particle surface area across a broad range of μC. The surface-carbon coverage is predicted to steadily increase for all low-index facets under more carburizing reaction conditions, leading to distinct effects on the adsorption energetics for atomic hydrogen and oxygen. Whereas H binding is only slightly affected by surface carbon, O is systematically destabilized. The findings reported indicate that consideration of only bulk-terminated surfaces, and the common focus of theoretical studies on the bulk-truncated, close-packed (1 0 0) surface, is likely insufficient to capture the reactivity of the working β-Mo2C catalyst. Similar to metal oxides, β-Mo2C catalysts are predicted to be dynamic materials with surface compositions and reactivities that evolve in response to the environment.

Original languageAmerican English
Article number153415
Number of pages12
JournalApplied Surface Science
StatePublished - 2022

Bibliographical note

Publisher Copyright:
© 2022 Elsevier B.V.

NREL Publication Number

  • NREL/JA-5100-82624


  • Density functional theory
  • Molybdenum carbide
  • Reconstruction
  • Surface stability
  • Wulff construction


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