王令光,张敏华,姜浩锡.镍表面单原子台阶对甲烷解离过程影响的DFT研究[J].分子催化,2005,(4):293-297
镍表面单原子台阶对甲烷解离过程影响的DFT研究
A DFT Study on the Influence of Step Structure of Nickel Surface on Methane Dissociation Process
投稿时间:2005-02-07  修订日期:2005-03-31
DOI:
中文关键词:  甲烷  部分氧化  密度泛函理论  解离  台阶结构
英文关键词:Methane,Partial Oxidation,Density Functional Theory (DFT),Dissociation,Step Structure
基金项目:
王令光  张敏华  姜浩锡
天津大学石油化工技术开发中心绿色合成与转化教育部重点实验室,天津300072
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中文摘要:
      使用基于密度泛函理论(DFT)的DMol^3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。
英文摘要:
      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 CH_ x (x0~4) on different active sites of the surface are discussed. LST/QST method has been carried out on searching for reaction pathways, transition states and corresponding reaction data of all dissociation steps of CH_ x (x1~4). Calculation results show that the step structure is more beneficial to CH_ x adsorption comparing with plan structure. There are active sites on step structure, which can reduce energy barrier of CH_ x dissociation. The decomposition processes of CH_ 4 and CH are key steps of the whole process of CH_ 4 dissociation, corresponding active energy can be reduced at special sites on stepped Ni surface.
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