Acta Phys. -Chim. Sin. ›› 2008, Vol. 24 ›› Issue (08): 1366-1370.doi: 10.3866/PKU.WHXB20080807

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Adsorption of Methyl, Amido and Methylamine Species on the Clean and C(N, O) Modified Mo(100) Surfaces

LV Cun-Qin; LING Kai-Cheng; SHANG Zhen-Feng; WANG Gui-Chang   

  1. College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan 030024, P. R. China; College of Chemistry and Chemical Engineering, Shanxi Datong University, Datong 037009, Shanxi Province, P. R. China; College of Chemistry, Nankai University, Tianjin 300071, P. R. China
  • Received:2008-03-21 Revised:2008-04-28 Published:2008-08-06
  • Contact: LING Kai-Cheng; WANG Gui-Chang;

Abstract: The adsorption of the species(CH3, NH2, and CH3NH2) on clean and carbon(nitrogen or oxygen) modified
Mo(100) surfaces has been investigated by the first-principles DFT-GGA calculations with the slab model. The calculated results showed that the adsorption energies of the adsorbed species(CH3, NH2 and CH3NH2) changed a little with the coverage of θ=1/6 ML (monolayer); but an obvious change could be observed at the relative higher coverage (θ=1/4 ML). In addition, it was found that the adsorption energies were lower on the modified Mo(100) surface as compared with the results on clean Mo(100) surface, and the activity of the Mo(100) surface decreased in the presence of the pre-adsorbed C(N, O) atoms with the order of C>N>O. It may be due to the reason that these electronegative atoms reduce the capability of electron donation of the metal, which results in the downshift of the surface metal atom d-band center. By the analysis of the density of state(DOS) projected onto Mo d-band, it can be found that d-band center only account for the diversification of the surface caused by the pre-adsorbed atoms, whereas the dz2-center can explain the changing trend of the adsorption energies more exactly.

Key words: DFT-GGA, Slab model, Adsorption, Mo(100), C(N, O) modified Mo(100) surfaces


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