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

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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