Density functional theoretical study of Cun, A1n, (n-4-31) and copper doped aluminum clusters:: Electronic properties and reactivity with atomic oxygen

SURFACE SCIENCE

卷:601

Review

Lacaze-Dufaure, Corinne ; Blanc, Christine ; Mankowski, Georges ; Mijoule, Claude

关键词: aluminum;    bimetallic;    cluster;    copper;    density functional theory;    oxygen;    surface reactivity;   

DOI  :  10.1016/j.susc.2007.01.015

来源: Elsevier

【 摘 要 】

A DFT study of the electronic properties of copper doped aluminum clusters and their reactivity with atomic oxygen is reported. Firstly we performed calculations for the pure Cu-n and Al-n (n = 4, 9, 10, 13, 25 and 31) clusters and we determined their atornization energy for some frozen conformations at the B3PW91 level. The calculated work functions and M-M (M = Cu, Al) bond energies of the largest clusters are comparable with experimental data. Secondly, we focused our attention on the change of the electronic properties of the systems upon the substitution of an Al atom by a Cu one. This latter stabilizes the system as the atornization energy of the 31-atoms cluster increases of 0.31 eV when the substitution is done on the surface and of 1.18 eV when it is done inside the cluster. We show that the electronic transfer from the Al cluster to the Cu atom located at the surface is large (equal to 0.7 e(-)) while it is negligible when Cu is inserted in the Al-n cluster. Moreover, the DOS of the Al-31 and Al30Cu systems are compared. Finally, the chemisorption energies of atomic oxygen in threefold sites of the Al-31, Cu-31 and Al30Cu clusters are calculated and discussed. We show that the chemisorption energy of 0 is decreasing on the bimetallic systems compared to the pure aluminum cluster. (c) 2007 Elsevier B.V. All rights reserved.

【 授权许可】

Free