First-principles calculations based on density functional theory （DFr） and the generalized gradient approximation （GGA） have been used to study the adsorption of CO molecule on the Cu2O（111） oxygen-vacancy surfa...First-principles calculations based on density functional theory （DFr） and the generalized gradient approximation （GGA） have been used to study the adsorption of CO molecule on the Cu2O（111） oxygen-vacancy surface. Calculations indicate that the C-O bond is weakened upon adsorption compared with that over perfect surface. In addition, with the density increase of the defective sites, the adsorption energies of the defect-CO configuration increase whereas the C-O bond nearly remains constant.展开更多
The adsorptions of CO and 02 molecules individually on the stoichiometric Cu-terminatcd Cu20 （111） surface are investigated by first-principles calculations on the basis of the density functional theory. The calcula...The adsorptions of CO and 02 molecules individually on the stoichiometric Cu-terminatcd Cu20 （111） surface are investigated by first-principles calculations on the basis of the density functional theory. The calculated results indicate that the CO molecule preferably coordinates to the Cu2 site through its C atom with an adsorption energy of-1.69 eV, whereas the 02 molecule is most stably adsorbed in a tilt type with one O atom coordinating to the Cu2 site and the other O atom coordinating to the Cul site, and has an adsorption energy of -1.97 eV. From the analysis of density of states, it is observed that Cu 3d transfers electrons to 2π orbital of the CO molecule and the highest occupied 5σ orbital of the CO molecule transfers electrons to the substrate. The sharp band of Cu 4s is delocalized when compared to that before the CO molecule adsorption, and overlaps substantially with bands of the adsorbed CO molecule. There is a broadening of the 2π orbital of the 02 molecule because of its overlapping with the Cu 3d orbital, indicating that strong 3d-2π interactions are involved in the chemisorption of the 02 molecule on the surface.展开更多
基金Supported by the National Natural Science Foundation of China (No. 10676007) and NCETFJ
文摘First-principles calculations based on density functional theory （DFr） and the generalized gradient approximation （GGA） have been used to study the adsorption of CO molecule on the Cu2O（111） oxygen-vacancy surface. Calculations indicate that the C-O bond is weakened upon adsorption compared with that over perfect surface. In addition, with the density increase of the defective sites, the adsorption energies of the defect-CO configuration increase whereas the C-O bond nearly remains constant.
基金Project supported by the National High Technology Research and Development Program of China (Grant No. 2009AA03 Z428)the National Natural Science Foundation of China (Grant No. 50872005)+1 种基金the National Basic Research Program of China (Grant No. 2007CB613306)the Innovation Foundation of BUAA for Ph. D. Graduates
文摘The adsorptions of CO and 02 molecules individually on the stoichiometric Cu-terminatcd Cu20 （111） surface are investigated by first-principles calculations on the basis of the density functional theory. The calculated results indicate that the CO molecule preferably coordinates to the Cu2 site through its C atom with an adsorption energy of-1.69 eV, whereas the 02 molecule is most stably adsorbed in a tilt type with one O atom coordinating to the Cu2 site and the other O atom coordinating to the Cul site, and has an adsorption energy of -1.97 eV. From the analysis of density of states, it is observed that Cu 3d transfers electrons to 2π orbital of the CO molecule and the highest occupied 5σ orbital of the CO molecule transfers electrons to the substrate. The sharp band of Cu 4s is delocalized when compared to that before the CO molecule adsorption, and overlaps substantially with bands of the adsorbed CO molecule. There is a broadening of the 2π orbital of the 02 molecule because of its overlapping with the Cu 3d orbital, indicating that strong 3d-2π interactions are involved in the chemisorption of the 02 molecule on the surface.
