Pd_4四面体掺杂石墨烯储氢的第一性原理计算

First-Principles Plane Wave Calculations: Molecular and Dissociative Adsorption of Hydrogen Molecule on Tetrahedral Pd_4 Clusters Decorated Graphene

采用第一性原理计算了Pd_4四面体掺杂石墨烯储氢的晶格结构常数、能量、电子态密度和电子结构。能量和电子结构分析显示:Pd原子转移了它的部分3d_(2z)轨道电子到石墨烯的π*,随后石墨烯反转移了部分π轨道电子到Pd的3d_(xz)+3d_(yz)轨道。由于Pd_4四面体之间的相互排斥力,它们之间没有形成团簇。在氢分子吸附Pd_4四面体掺杂石墨烯的体系中,发现Pd_4四面体顶部的Pd原子电荷发生了改变,从而加强了氢分子的吸收能和储存能。以上结果显示:对于石墨烯储氢,Pd_4四面体是良好的催化剂。

Graphene using first-principles density of electronic analysis denotes that doped with tetrahedral Pd4 clusters for hydrogen adsorption was investigated plane wave simulations, including its lattice constant, vibrational energetics, states and electronic structure. The vibrational energetic and electronic structure palladium clusters transfer their 3dz^2 charge to μ^＊ band of graphene, and then π orbital of graphene is back transferred its charge to the 3dxz ＋ dyz orbital of palladium atoms. And the aggregation of Pd4 clusters is hampered by the repulsion force between Pd4 clusters. It is found that hydrogen molecule adsorbed on Pd4 clusters-doped graphene makes the top palladium atom of Pd4 clusters charge alternate, which enhances the hydrogen molecule adsorption energy. These results indicate that the Pd4 clusters-doped graphene may serve as a good catalyst of H2 adsorption.