O_2在M_2^-(M=Au,Ag,Cu,Pt)系列团簇上的吸附行为研究

Adsorption Behavior of M_2^-(M=Au,Ag,Cu,Pt) Serial Clusters with O_2

用密度泛函理论(DFT)方法研究了O2在M2-(M=Au,Ag,Cu,Pt)系列团簇上的吸附行为,首次确定存在2个O原子与同一个Au作用的吸附方式(记为D2),并讨论了该吸附方式对Au2-催化CO氧化的重要作用.结果表明,相对于研究者所关注的O原子与Au作用的D1吸附方式,D2吸附方式的O2分子活化程度更高,更有利于促进CO氧化.相对D1吸附方式,从D2式出发,CO按Eley-Rideal机理插入形成Au2CO3-的势垒更低,稳定性更高,更有利于CO2脱附.Ag体系的计算结果与Au类似,Cu、Pt体系则明显不同.

Density function theory is used to study the adsorption behavior of M 2-（M = Au,Ag,Cu,Pt） serialclusters with O2.For the first time we confirm the exsistence of the adsorption mode of two O atoms with thesame one Au atom（denoted D2）,and discuss the important action of Au2-catalytic oxidation of CO by thismode.The results show that D2 mode is more beneficial to activation of O2 and oxidation of CO compaired withD1 mode.According to Eley-Rideal machanism,when CO is inserted in Au2O 2-to form Au2CO 3-,D2 modehas lower barrier and higher stability,and is more favourable to desorption of CO2.The result of Ag is similarto that of Au but unlike those of Cu and Pt.