Acta Phys. -Chim. Sin. ›› 2011, Vol. 27 ›› Issue (10): 2319-2325.doi: 10.3866/PKU.WHXB20110936


Adsorption and Dissociation of CO2on the α-U(001) Surface

LI Gan1, LUO Wen-Hua1, CHEN Hu-Chi2   

  1. 1. Key Laboratory for Surface Physics and Chemistry, Mianyang 621907, Sichuan Province, P. R. China;
    2. China Academy of Engineering Physics, Mianyang 621900, Sichuan Province, P. R. China
  • Received:2011-04-28 Revised:2011-07-12 Published:2011-09-27
  • Contact: LI Gan
  • Supported by:

    The project was supported by the Key Laboratory Foundation of Science and Technology of National Defense, China (9140C6601010901) and Science and Technology Foundation of China Academy of Engineering and Physics (2008A0301013).

Abstract: The adsorption and dissociation of CO2 on the α-U(001) surface at 0.25 monolayer (ML) coverage was studied using density functional theory (DFT) within the generalized gradient approximation (GGA). Stable structures and corresponding energies of CO2 adsorbed on the α-U(001) surface were obtained while the transition state and corresponding energy barrier for CO2 dissociation was determined. We discussed the interaction mechanism between CO2 and the α-U(001) surface. We found that CO2 strongly chemisorbed onto the α-U(001) surface in a multi-bonding manner with adsorption energies of 1.24-1.67 eV and the degree of C―O bond activation depended on the degree of electron transfer from surface to the adsorbed CO. The interaction between the U atoms and the CO2 molecules mainly comes from the population of the CO2 2πu lowest unoccupied molecular orbital (LUMO) by U electrons with CO2 2πu/1πg/3σu-U 6d orbital hybridization. The dissociative adsorption energies for the CO2 adsorbed on the hollow1 and hollow2 sites with three C―U bonds and six O―U bonds (H1-C3O6 and H2-C3O6 ) are 3.15 and 3.13 eV, respectively. The corresponding dissociation barriers are 0.26 and 0.36 eV, which indicates that the dissociation of adsorbed CO2 into CO and O occurs easily.

Key words: Density functional theory, &, alpha, -U(001) surface, Carbon dioxide, Adsorption


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