物理化学学报 >> 2006, Vol. 22 >> Issue (03): 345-349.doi: 10.3866/PKU.WHXB20060318

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柠檬酸溶胶-凝胶法制备的纳米Ce1-xMnxO2: 织构与晶相结构

叶青; 徐柏庆   

  1. 清华大学化学系, 有机光电子与分子工程教育部重点实验室, 分子催化与定向转化研究室, 北京 100084
  • 收稿日期:2005-07-12 修回日期:2005-09-02 发布日期:2006-03-10
  • 通讯作者: 徐柏庆 E-mail:bqxu@mail.tsinghua.edu.cn

Textural and Structure Characterizations of Ce1-xMnxO2Prepared by Citric Acid Sol-Gel Method

YE Qing; XU Bo-Qing   

  1. Innovative Catalysis Program, Key Laboratory of Organic Optoelectronics & Molecular Engineering, Department of Chemistry, Tsinghua University, Beijing 100084, P. R. China
  • Received:2005-07-12 Revised:2005-09-02 Published:2006-03-10
  • Contact: XU Bo-Qing E-mail:bqxu@mail.tsinghua.edu.cn

摘要: 采用N2-吸附/脱附、XRD、Raman光谱和TEM等表征技术研究了柠檬酸溶胶-凝胶法制备的Ce1-xMnxO2 (0≤x≤1) 样品的织构及晶相结构.结果表明, Ce1-xMnxO2 样品的N2吸附等温线为IV型, 滞后环为H1型, 最可几孔径处在2.5~3.7 nm范围.由XRD测得的样品晶粒大小与由TEM测定的颗粒尺寸相近, 表明制备的样品具有较好的分散性, 但是样品的组成对颗粒大小有明显的影响, Mn浓度适中样品(x=0.3~0.7)的颗粒(1~5 nm)明显小于低Mn浓度样品(x<0.3)和高Mn浓度样品(x>0.7)的颗粒(10~50 nm).尽管在x>0.7时, XRD未能检测到样品中有α-Mn2O3晶粒存在, 但Raman光谱结果表明, 所有Ce1-xMnxO2混合氧化物均以α-Mn2O3相和立方CeO2相Ce-Mn-O固溶体形式存在.

关键词: Ce1-xMnxO2, 溶胶-凝胶法, N2-吸附/脱附, XRD, Raman光谱, TEM

Abstract: Textural and structure characterizations of Ce1-xMnxO2 (0≤x≤1) samples were studied by N2 adsorption/desorption, XRD and Raman spectroscopy. The N2 adsorption/desorption isotherms are found to be IV-type according to BDDT and their related hysteresis loops are H1 type. Pore size distribution of the Ce1-xMnxO2 samples is in the mesopores range with Rp (max) between 2.5 nm and 3.7 nm. Particle sizes of the samples with both high Mn (x>0.7) and low Mn (x<0.3) contents are larger than those with 0.3≤x≤0.7. Raman spectroscopic results show that the Ce1-xMnxO2 (x≠0, 1) samples contain mixed phases of α-Mn2O3 and Ce-Mn-O solid solution, although the presence of α-Mn2O3 phase is not detected in the XRD measurement of the samples with x≤0.7, suggesting that Raman spectroscopy is more sensitive in the structural characterization of Ce1-xMnxO2 samples.

Key words: Ce1-xMnxO2, Sol-gel preparation, N2/adsorption-desorption, XRD, Raman spectrum, TEM