Stable surface terminations of orthorhombic Mo2C catalysts and their CO activation mechanisms

Tao Wang, Qiquan Luo, Yong Wang Li, Jianguo Wang, Matthias Beller, Haijun Jiao

Research output: Contribution to journalArticlepeer-review

37 Scopus citations

Abstract

The structure and stability of all twenty-two terminations of the seven low-Miller index orthorhombic Mo2C surfaces have been systematically investigated on the basis of the computed surface energies from periodic density functional theory. With the increase of the carbon chemical potential (μC), the most stable surface structure and composition change from the metallic (1 1 0)-Mo and (1 0 0)-Mo terminations to the mixed (1 1 1)-Mo/C and strongly reconstructed (1 1 0)-Mo/C terminations. The calculated stability order and surface area proportions of the (1 0 0), (1 1 0) and (1 1 1) surfaces agree very well with the available X-ray diffraction data. In addition, CO adsorption and dissociation on these surfaces have been computed and micro-kinetic analysis reveals that CO dissociation is rate-determining on the metallic termination, and CO adsorption is rate-determining on the mixed Mo/C-termination. This might explain the observed catalytic differences of orthorhombic Mo2C catalysts prepared from different ways.

Original languageEnglish
Pages (from-to)146-156
Number of pages11
JournalApplied Catalysis A: General
Volume478
DOIs
StatePublished - 20 May 2014
Externally publishedYes

Keywords

  • CO activation
  • DFT
  • Morphology
  • Surface energy

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