中国科学院大连化学物理研究所机构知识库
Advanced  
DICP OpenIR  > 中国科学院大连化学物理研究所  > 会议论文
学科主题: 物理化学
题名: Density functional theory study of CHx (x=1-3) adsorption on clean and CO pre-covered Rh(111) surface
作者: Yang MM(杨明媚) ;  Bao XH(包信和) ;  Li WX(李微雪)
会议名称: 13th International Conference on Surface Science
会议日期: 2007-7-2
出版日期: 2007-07-02
会议地点: Sweden
通讯作者: 李微雪
部门归属: 五室
摘要: CHx (x=1-3) species, central in many catalytic reactions occurring on transition metal surfaces, have been extensively studied from both of experimental and theoretical points of view. Among them, rhodium is a unique catalyst due to its high selectivity and activity for the synthesis of higher oxygenated compounds, especially in methane partial oxidation to syngas and subsequent C2-oxygenates. Although significant efforts have been pursued on the experimental characterization of small hydrocarbons on Rh surfaces, there are still many remain. For example, in CO hydrogenation over promoted Rh catalysts it is widely accepted that during the formation of C2-oxygenates, CO is inserted into the surface-alkyl group and generates CHxCO species. There is, however, no agreement on which CHx species will be inserted by CO. [1-2] To unravel the microscopic mechanisms, it is mandatory to study the elementary steps for insertion which begins with co-adsorption of CHx and CO on these surfaces, and studied by density functional theory calculations.[3] It is found that CHx (x=1-3) radicals prefer three-fold hollow sites on Rh(111) surfaces, and the bond strength between CHx and Rh(111) follows the order of CH3 < CH2 < CH. When the coverage is larger than 1/4 ML, considerable repulsion is built up between adsorbates. We find that surface work function decreases after CHx adsorption due to charge transfer from the radicals to the substrate. For adsorbed CH3, charge back donation from the substrate to C-H bond is identified and results in C-H stretch mode-softening. The mode-softening is however prevented by co-adsorbed CO via charge competition. Conversely, C-O stretch is softened by enhanced backfilling of anti-bonding states of five sigma orbital from the CH3. Finally, the C 1s surface core level shifts (SCLS) for CHx with and without the presence of CO are calculated, and compared with experiments.
语种: 中文
内容类型: 会议论文
URI标识: http://cas-ir.dicp.ac.cn/handle/321008/112798
Appears in Collections:中国科学院大连化学物理研究所_会议论文

Files in This Item:

There are no files associated with this item.


Recommended Citation:
Yang MM,Bao XH,Li WX. Density functional theory study of CHx (x=1-3) adsorption on clean and CO pre-covered Rh(111) surface[C]. 见:13th International Conference on Surface Science. Sweden. 2007-7-2.
Service
 Recommend this item
 Sava as my favorate item
 Show this item's statistics
 Export Endnote File
Google Scholar
 Similar articles in Google Scholar
 [杨明媚]'s Articles
 [包信和]'s Articles
 [李微雪]'s Articles
CSDL cross search
 Similar articles in CSDL Cross Search
 [杨明媚]‘s Articles
 [包信和]‘s Articles
 [李微雪]‘s Articles
Related Copyright Policies
Null
Social Bookmarking
  Add to CiteULike  Add to Connotea  Add to Del.icio.us  Add to Digg  Add to Reddit 
所有评论 (0)
暂无评论
 
评注功能仅针对注册用户开放,请您登录
您对该条目有什么异议,请填写以下表单,管理员会尽快联系您。
内 容:
Email:  *
单位:
验证码:   刷新
您在IR的使用过程中有什么好的想法或者建议可以反馈给我们。
标 题:
 *
内 容:
Email:  *
验证码:   刷新

Items in IR are protected by copyright, with all rights reserved, unless otherwise indicated.

 

 

Valid XHTML 1.0!
Powered by CSpace