引用本文:
【打印本页】   【HTML】   【下载PDF全文】   查看/发表评论  【EndNote】   【RefMan】   【BibTex】
过刊浏览    高级检索
本文已被:浏览 303次   下载 142  
分享到: 微信 更多
采用(meta)-GGA泛函对Ag(111), Rh(111)和Ir(111) 上乙烯吸附的理论研究
李微雪
作者单位E-mail
李微雪 中国科学院大连化学物理研究所催化基础国家重点实验室 wxli70@ustc.edu.cn 
摘要:
通过理论模拟准确描述金属表面的分子吸附过程对于研究金属催化剂的活性和选择性机理至关重要。然而由于缺乏能同时描述多种相互作用类型的交换关联泛函,第一性原理方法在催化领域的应用依然充满挑战。我们针对在多种催化反应的重要中间体乙烯,使用(meta)-GGA等级的包含PBE,BEEF-vdW,SCAN以及SCAN+rVV10在内的多种交换关联泛函,系统研究了在过渡金属金属表面(Ag,Rh和Ir)上的乙烯吸附势能面对泛函的依赖关系。研究发现,对于乙烯在贵金属Ag(111)上的吸附,除了PBE外,BEEF-vdW,SCAN以及SCAN+rVV10均能预测出物理吸附态的存在。对于乙烯在Rh(111)面的吸附,SCAN和SCAN+rVV10预测在化学吸附位之前存在有物理吸附前驱态,而基于PBE和BEEF-vdW的势能面并没有发现前驱态的存在。而对于乙烯在Ir(111)上的吸附,BEEF-vdW也能微弱得预测出化学吸附前驱态的存在。研究结果表明,无论在那一种金属表面上,四种泛函中SCAN+rVV10给出的吸附能最强,其次是SCAN,然后是PBE或者BEEF-vdW。当前的工作突出了乙烯吸附势能面对于过渡金属组分和第一性原理计算方法的巨大依赖性,而这一依赖性也为新的交换关联泛函的发展提供了很好地基准测试对象。
关键词:  乙烯吸附,势能面,过渡金属表面,交换关联泛函,第一性原理
DOI:
分类号:
基金项目:
Ethylene Adsorption on Ag(111), Rh(111) and Ir(111) by (meta)-GGA based Density Functional Theory Calculations
李微雪
Abstract:
Accurate description of the adsorption process of reactants on metal surfaces from theory is crucial for mechanistic understanding of activity and selectivity of metal catalysts but remains challenge for the nowadays first-principles theory due to the lack of proper exchange-correlation functional describing the distinct interactions involved. We studied here the potential energy surfaces of ethylene adsorption on Ag(111), Rh(111) and Ir(111) using density functional theory calculations and (meta)-GGA functional including PBE, BEEF-vdW, SCAN, and SCAN+rVV10. For ethylene adsorption on noble metal Ag(111), it is found that BEEF-vdW, SCAN and SCAN+rvv10 predict the presence of the physisorption states only. For Rh(111), both SCAN and SCAN+rvv10 find that there is a precursor physisorption state before the chemisorption state. In contrast, there is no precursor state found based on potential energy surfaces from BEEF-vdW and PBE. Whereas for Ir, BEEF-vdW predicts the existence of a rather shallow precursor physisorption state, in addition to the chemisorption state. Irrespective to the transition metals considered, we find that SCAN+rVV10 gives the strongest binding strength, followed by SCAN, and PBE/BEEF-vdW, accordingly. The present work highlights great dependence of potential energy surface of ethylene adsorption on transition metal surfaces and exchange-correlation functionals.
Key words:  Ethylene adsorption, Potential energy curve, Transition metal surface, Exchange-correlation functionals, First-principles theory