摘要
使用基于密度泛函理论(DFT)的DMol3量子力学计算程序模块,采用Ni(211)周期性模型表达镍表面上的单原子台阶结构,计算出CHx(x=0～4)在Ni(211)模型不同活性位上的吸附能和空间构型,并使用LST/QST方法找到了台阶结构上CHx(x=1～4)的解离路径、过渡态和相应的能量数据.计算结果表明,金属表面台阶结构较平台结构更有利于CHx物种的吸附.台阶结构上存在能够降低CHx解离活化能的活性位.处于台阶结构上的特定位置时,CH4解离全过程的关键步骤-CH4和CH解离的活化能会大幅降低.
DMol^3 module based on density functional theory （DFT） has been used for Ni （211） slab model to simulate monatomic step structure. Results of adsorption energy and space configurations of CHx（x=0-4） on different active sites of the surface are diccussed. LST/QST method has been carrled out on searching for reaction pathways, transition states and corresponding reaction data of all dissociation steps of CHx（x=1-4）. Calculation results show that the step structure is more beneficial to CHx adsorption comparing with plan structure. There are active sites on step structure, which can reduce energy barrier of CHx dissociation. The decomposition processes of CH4 and CH are key steps of the whole process of CH4 dissociation, corresponding active energy can be reduced at special sites on stepped Ni surface.
出处
《分子催化》
EI
CAS
CSCD
北大核心
2005年第4期293-297,共5页
Journal of Molecular Catalysis(China)
关键词
甲烷
部分氧化
密度泛函理论
解离
台阶结构
Methane
Partial Oxidation
Density Functional Theory （DFT）
Dissociation
Step Structure
