Pt?Cu簇合金表面上H_2O与CO吸附的DFT理论研究

A DFT Theoretical Investigation of Adsorption of H_2O and CO on Pt/Cu Cluster Surfaces

采用广义梯度近似(GGA)的密度泛函理论(DFT),结合簇模型,研究了H_2O、CO在清洁及Cu置换后的Pt(111)簇表面的吸附行为。计算结果表明,吸附物种的吸附能变化与Cu的位置有关。与Cu在其他位置的簇表面上的吸附相比,在Cu置换最外层中心位置的Pt(111)簇表面的吸附最稳定;在Cu置换次外层中心位置的Pt(111)簇(该簇具有最好的稳定性)上的吸附最不稳定。CO的吸附研究表明,最稳定吸附位是hcp位,与在纯Pt簇上的吸附相同。

The adsorption of H_2O and CO on clean and Cu transpositional Pt（111）cluster surfaces has been investigated by the first-principles DFT-GGA calculations with the cluster model.The calculated results show that the adsorption energies of the adsorbed species（CO,H_2O）change with the site of Cu.Especially,it was found that the adsorption on the surface of Pt（111）cluster with transpositional Cu in the center of surface has best stability in comparison with that on the surface of cluster with transpositional Cu in other sites.But the adsorption on the surface of Pt（111）cluster with transpositional Cu in the center of subsurface（which has best stability）has most instability.The study of adsorption with CO shows that hcp site is the most stable adsorption site,the same with that on pure Pt.