Pdn(n=1-7)团簇及其与甲烷相互作用的密度泛函理论研究

用密度泛函理论(DFT)的B3LYP方法, 对Pdn(n=1-7)团簇的几何结构、振动频率及其与甲烷分子间的相互作用进行了理论研究. 结果表明, 随着Pd原子数增多, 团簇结构对团簇大小的依赖性减弱, 结构参数向金属晶体趋近. 在Pdn(n=1-7)团簇上, 甲烷的表面吸附作用较弱. Pd2CH4中, 甲烷受到两个Pd原子的活化作用, 活化程度增强, 吸附能增大. 在PdnCH4 (n=1, 3-7)体系中, 甲烷的吸附能随着团簇模型的增大而减小, 趋近于其在金属晶面上的吸附能.

A DFT Study of Pdn(n=1-7) Clusters and Their Interactions with CH4 Molecule

The geometric configurations,vibrational frequencies of Pd_n(n=1-7) clusters and their interactions with a CH4 molecule were studied using the DFT/B3LYP method.Increasing the total number of palladium atoms made the cluster less size-dependent and structural parameters approach to the bulk solid.Methane adsorption on Pd_n(n=1-7) clusters was very weak.Methane was activated by Pd_2 cluseter,activation and adsorption energy were aggrandized. With increasing cluster size,the interaction of molecular-surface in Pd_nCH_4 (n=1,3-7) clusters became weak,and the adsorption energy approached to that on the bulk metal.