Acta Phys. -Chim. Sin. ›› 2013, Vol. 29 ›› Issue (02): 365-370.doi: 10.3866/PKU.WHXB201211144

• CATALYSIS AND SURFACE SCIENCE • Previous Articles     Next Articles

Effects of O Coverage on the Dissociation of O2 Molecules on the Nb(110) Surface

WANG Qing-Gao, SHANG Jia-Xiang   

  1. School of Materials Science and Engineering, Beihang University, Beijing 100191, P. R. China
  • Received:2012-09-20 Revised:2012-11-14 Published:2013-01-14
  • Supported by:

    This work was supported by National Natural Science Foundation of China (51071011).

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Abstract:

The effects of oxygen atom coverage on the dissociation of O2 molecules at the Nb(110) surface were investigated using density functional theory (DFT) methods. The dissociation of O2 molecules is facile at low O coverages [Θ≤0.50 monolayer (ML)] because of the strong electronic interaction between O2 molecules and the Nb substrate. At a coverage of 0.75 ML, O2 molecules next to unoccupied distorted four-fold (H4d) sites only dissociate with severe lattice distortions. However, the inward diffusion of O atoms is the rate limiting step for the dissociation of O2 molecules after adsorption of 1.00 ML O atoms. Overall, our theoretical study provides a rationale for the experimental result that the dissociation of O2 molecules decreases markedly after rapid adsorption of 1.00 ML O atoms on the low index Nb surfaces.

Key words: Density functional theory, O atom, O2 molecule, Nb(110) surface