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: Redox characteristics of the LaFe1-xPdxO3 perovskites prepared by a simple sol-gel process
作者: Zhang XJ(张晓静) ;  Li HJ(李华举) ;  Li Y(李勇) ;  Shen WJ(申文杰)
会议名称: 6th International Conference on Environmental Catalysis
会议日期: 2010-9-12
出版日期: 2010-09-12
会议地点: 中国
其他题名: 简单溶胶-凝胶法制备的LaFe1-xPdxO3钙钛矿型复合氧化物的氧化还原性能
通讯作者: 申文杰
ISSN: 
部门归属: 五室
主办者: 中国科学院生态环境研究中心
摘要: Introduction The precious metal substituted perovskites, LaFe0.57Co0.38Pd0.05O3, CaTi0.95Pt0.05O3 and CaTi0.95Rh0.05O3, have been reported to be highly effective three-way catalysts for automobile exhaust elimination, in which precious metal incorporates into the B-site of the perovskite with a self-regenerative function.1, 2 However, these intelligent perovskites are usually prepared by hydrolysis of expensive metal organic precursors. Here we report that LaFe1-xPdxO3 perovskites could be prepared by a simple sol-gel method and the interaction manner between Pd and LaFeO3 is examined. Experimental The LaFe1-xPdxO3 perovskites (x = 0, 0.05, 0.08 and 0.11) were prepared by a sol-gel method. Briefly, the aqueous solution containing metal ions and complexing reagents was heated at 80 ℃ for 6 h under reflux, the excess water then was slowly evaporated. The brown sol obtained was dried at 100 ℃ overnight and calcined at 450 ℃ for 3 h and then 800 ℃ for 5 h in air. Results and Discussion All the samples exhibit typical diffractions of perovskite (Fig. 1A) and no diffractions of PdO or metallic Pd are observed. The lattice parameters of LaFe1-xPdxO3 slightly decrease with Pd loading in the samples with x = 0.05 and 0.08, indicating that Pd has doped into the lattice of LaFeO3 perovskite. The in-situ XRD patterns show that the perovskite structure is rather stable even up to 800 ℃ in H2, evidencing the excellent structural stability under reductive atmosphere. As shown in Fig. 1B, the reduction properties of the LaFe1-xPdxO3 samples vary remarkedly with Pd loading. The negative peaks around 45 ℃ of the samples with x = 0.05 and 0.08 could be attributed to the decomposition of β-palladium hydride phase. While for the sample of x = 0.11, the reduction peak at 90 ℃ is simply assigned to the reduction of PdO. In the Pd-perovskites, the surface reduction of Fe3+→Fe2+ overlaps with the bulk reduction at higher termperatures and all shift towards lower temperatures compared with LaFeO3. This verifies that Pd substitution facilitates the reduction of Fe ions and thus improves the reducibility of the perovskites. In the O2-TPD profiles (Fig. 1C), the desorption of lattice oxygen over the samples with x = 0.05 and 0.08 occurs at 600~900 ℃ and is more prominent than LaFeO3, indicating that Pd substitution has promoted the diffusion of bulk oxygen significantly. When the Pd content further increased up to 0.11, the desorption of lattice oxygen shifts to higher temperatures and the oxygen desorption amount decreases greatly, implyig not all the Pd has doped into the lattice of LaFeO3, which can accommodate no more than 11 at% on the B-site. However, catalytic performances of the LaFe1-xPdxO3 samples for CH4 combustion are almost the same, indicating that the promoted reducibility and the lattice oxygen mobility do not have great influence on the reaction behavior of perovskites. Study on the detailed reaction mechanism is undergoing. Conclusions Pd-substituted LaFe1-xPdxO3 perovskites with Pd content up to 8 at% were prepared by a simple sol-gel method. Pd substitution has significantly promoted the reducibility and lattice oxygen mobility of the perovskites. References [1] Y. Nishihata, J. Mizuki, T. Akao, H. Tanaka, et al., Nature 418 (2002) 164. [2] H. Tanaka, M. Taniguchi, M. Uenishi, N. Kajita, et al., Angew. Chem. Int. Ed. 45 (2006) 5998.
语种: 中文
内容类型: 会议论文
URI标识: http://cas-ir.dicp.ac.cn/handle/321008/114216
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:
Zhang XJ,Li HJ,Li Y,et al. Redox characteristics of the LaFe1-xPdxO3 perovskites prepared by a simple sol-gel process[C]. 见:6th International Conference on Environmental Catalysis. 中国. 2010-9-12.
Service
 Recommend this item
 Sava as my favorate item
 Show this item's statistics
 Export Endnote File
Google Scholar
 Similar articles in Google Scholar
 [张晓静]'s Articles
 [李华举]'s Articles
 [李勇]'s Articles
CSDL cross search
 Similar articles in CSDL Cross Search
 [张晓静]‘s Articles
 [李华举]‘s Articles
 [李勇]‘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