金镍六原子团簇吸附CO的密度泛函研究

DFT study on CO adsorption on six-atom AuNi clusters

在UBP86/LAN2DZ水平上计算了金镍二元团簇(AunNi6-n,n=0～6)吸附CO的稳定构型和相关性质。计算结果表明,AunNi6-nCO团簇的最低能量结构是在AunNi6-n团簇最低能量结构或亚稳态结构基础上吸附CO分子而形成。优化结构中C-O键长表明,吸附后的CO没有解离,即CO分子在AunNi6-n团簇表面发生非解离吸附。除Au6和Au5Ni团簇外,AunNi6-nCO团簇中C-O键长均在0.120 nm以上,CO分子的活化程度较大。除Au6团簇外,CO在AunNi6-n团簇表面的吸附能均比较大,表明CO吸附后不容易发生解离。

The adsorption of CO on gold-nickel binary clusters（AunNi6-n,n= 0 ~ 6）were investigated at the UBP86/LANL2DZ level.The computational results indicated that the lowest energy structures of AunNi6-nCO are still generated when CO is adsorbed onto AunNi6-n clusters.The lowest energy structures of AunNi6-n clusters are not changed by adsorbing CO molecules.Chemisorption of CO onto AunNi6-n cluster surfaces is a non-dissociative adsorption process.An increased theoretical CO bond length of 0.120-0.124 nm in AunNi6-nCO cluster（compared to 0.1166 nm in free CO molecule）indicates a strong activation for the C-O bond except for Au6.