物理化学学报 >> 2003, Vol. 19 >> Issue (06): 519-522.doi: 10.3866/PKU.WHXB20030608

研究论文 上一篇    下一篇

CuO/γ-Al2O3单分散催化剂的XAFS研究

陈栋梁;胡玉海;陈懿;张新夷;韦世强   

  1. 中国科学技术大学国家同步辐射实验室,合肥　230029;南京大学化学系,介观固体化学研究所,南京　210093;
  • 收稿日期:2002-09-24 修回日期:2003-01-02 发布日期:2003-06-15
  • 通讯作者: 韦世强 E-mail:sqwei@ustc.edu.cn

Monolayer Dispersive CuO/γ-Al2O3 Catalyst Studied by XAFS

Chen Dong-Liang;Hu Yu-Hai;Chen Yi;Zhang Xin-Yi;Wei Shi-Qiang   

  1. National Synchrotron Radiation Laboratory,University of Science and Technology of China,Hefei　230029;
  • Received:2002-09-24 Revised:2003-01-02 Published:2003-06-15
  • Contact: Wei Shi-Qiang E-mail:sqwei@ustc.edu.cn

PDF

3072

赞

摘要： 采用XAFS方法研究浸渍法制备并于低温焙烧的CuO/γ-Al2O3催化剂的局域结构.对于CuO负载量小于单层分散阈值的CuO/γ-Al2O3(0.4 mmol/100 m2),结果表明,CuO物种是以层状分散的孤立原子簇存在于γ-Al2O3载体表面,其第一近邻Cu－O配位环境的结构与晶态CuO的相似,键长和配位数分别为0.195 nm和4.对于CuO负载量等于单层分散阈值的CuO/γ-Al2O3(0.8 mmol/100 m2),已有少量的CuO纳米颗粒生成.对于CuO负载量大于单层分散阈值的CuO/γ-Al2O3(1.2 mmol/100 m2),其结构与多晶CuO的相近.基于CuO在γ-Al2O3载体上的三种不同分散状态的结构特点,我们提出了CuO/γ-Al2O3催化剂的结构模型.

关键词: 单层分散, CuO, XAFS

Abstract: The local structures of monolayer dispersive CuO/γ-Al2O3 catalysts prepared by means of impregnation have been investigated by XAFS technique.For the CuO/γ-Al2O3 sample with CuO loading 0.4 mmol/100 m2 lower than the monolayer dispersion threshold,the XAFS results indicate that only the first coordination shell appears in the radial distribution function of Cu atoms,and that the RCu－O and coordination number in the first shell are 0.195 nm and 4,respectively.Hence,we consider that the CuO active species on the surface of γ-Al2O3 are in the form of isolated atomic cluster ().Small amount of CuO nano-grains is formed onto the surface of γ-Al2O3 while the CuO loading is just equal to the threshold 0.8 mmol/100 m2.For sample with CuO loading of 1.2 mmol/100 m2,the local structure of Cu atom in CuO/γ-Al2O3 is similar to that of CuO powder.On the basis of the XAFS results,a monolayer dispersion model of CuO/γ-Al2O3 catalysts has been proposed.

Key words: Monolayer dispersion, CuO, XAFS(X-ray adsorption fine structure)