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  > 期刊论文
题名: Restructuring and redispersion of silver on SiO2 under oxidizing/reducing atmospheres and its activity toward CO oxidation
作者: Qu, ZP;  Huang, WX;  Cheng, MJ;  Bao, XH
通讯作者: 包信和
刊名: JOURNAL OF PHYSICAL CHEMISTRY B
发表日期: 2005-08-25
DOI: 10.1021/jp050152m
卷: 109, 期:33, 页:15842-15848
收录类别: SCI
文章类型: Article
部门归属: 5
项目归属: 502
产权排名: 1;1
WOS标题词: Science & Technology ;  Physical Sciences
类目[WOS]: Chemistry, Physical
研究领域[WOS]: Chemistry
英文摘要: The effects of oxygen-hydrogen pretreatments of nanosilver catalysts in cycle mode on the structure and particle size of silver particles, and subsequently the activity of the catalyst toward CO oxidation (or CO selective oxidation in the presence of H-2) are reported in this paper. Ag/SiO2 catalyst with silver particle sizes of ca. 6 similar to 8 nm shows relatively high activity in the present reaction system. The adopting of a cycle of oxidation/reduction pretreatment has a marked influence on the activity of the catalyst. Oxygen pretreatment at 500 degrees C results in the formation of subsurface oxygen and activates the catalyst. As evidenced by in-situ XRD and TEM, the following H-2 treatment at low temperatures (100 similar to 300 degrees C) causes surface faceting and redispersing of the silver particles without destroying the subsurface oxygen species. The subsequent in-situ FTIR and catalytic reaction results show that CO oxidation occurs at -75 degrees C and complete CO conversion can be obtained at 40 degrees C over such a nanosilver catalyst pretreated with oxygen at 500 degrees C followed by H-2 at 100 degrees C. However, prolonged hydrogen treatment at high temperatures (> 300 degrees C) after oxygen pretreatment at 500 degrees C induces the aggregation of silver particles and also depletes so much subsurface oxygen species that the pathway of CO oxidation by the subsurface oxygen species is inhibited. Meanwhile, the ability of the catalyst to adsorb reactants is greatly depressed, resulting in a 20 similar to 30% decrease in the activity toward CO oxidation. However, the activity of the catalyst pretreated with oxygen at 500 degrees C followed by hydrogen treatment at high temperatures (> 300 degrees C) is still higher than that directly pretreated with H,. This kind of catalytic behavior of silver catalyst is associated with physical changes in the silver crystallites because of surface restructuring and crystallite redispersion during the course of oxygen-hydrogen pretreatment steps.
关键词[WOS]: CARBON-MONOXIDE OXIDATION ;  SELECTIVE OXIDATION ;  PT/ALUMINA CATALYSTS ;  OXYGEN ;  SURFACE ;  GAS ;  TEMPERATURE ;  ADSORPTION ;  REDUCTION ;  ALUMINA
语种: 英语
原文出处: 查看原文
WOS记录号: WOS:000231426000029
Citation statistics: 
内容类型: 期刊论文
URI标识: http://cas-ir.dicp.ac.cn/handle/321008/93093
Appears in Collections:中国科学院大连化学物理研究所_期刊论文

Files in This Item: Download All
File Name/ File Size Content Type Version Access License
2005LMYTD23LM6.pdf(342KB)----开放获取--View Download

作者单位: 1.Chinese Acad Sci, Dalian Inst Chem Phys, State Key Catatlysis, Dalian 116023, Peoples R China

Recommended Citation:
Qu, ZP,Huang, WX,Cheng, MJ,et al. Restructuring and redispersion of silver on SiO2 under oxidizing/reducing atmospheres and its activity toward CO oxidation[J]. JOURNAL OF PHYSICAL CHEMISTRY B,2005,109(33):15842-15848.
Service
 Recommend this item
 Sava as my favorate item
 Show this item's statistics
 Export Endnote File
Google Scholar
 Similar articles in Google Scholar
 [Qu, ZP]'s Articles
 [Huang, WX]'s Articles
 [Cheng, MJ]'s Articles
CSDL cross search
 Similar articles in CSDL Cross Search
 [Qu, ZP]‘s Articles
 [Huang, WX]‘s Articles
 [Cheng, MJ]‘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 
文件名: 2005LMYTD23LM6.pdf
格式: Adobe PDF
此文件暂不支持浏览
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