A comparative UV–vis-diffuse reflectance study on the location and interaction of cerium ions in Al- and Zr-pillared montmorillonite clays

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• 作者：Rao ; G. Ranga ; Mishra ; Braja Gopal
• 关键词：Pillared clay ; UV&ndash ; vis-DRS ; Cerium ion ; XRD ; Montmorillonite
• 刊名：Materials Chemistry and Physics
• 出版年：2005
• 期刊代码：58_02540584
• 类别：ms
• 出版时间：January 15, 2005
• 卷：89
• 期：1
• 页码：110-115
• 文件大小：103 K

摘要

The environment, location and interaction of the Ce³⁺ ions in the micropores of Al- and Zr-pillared clays have been studied by UV–vis-diffuse reflectance spectroscopy (UV–vis-DRS). The DRS spectra show that the chemical environment of the Ce³⁺ ions in cerium exchanged clay is different from that of the Al- and Zr-pillared clays. The Al–Ce pillared clays (Al–Ce-PM) show four distinct absorption bands at 224, 263, 294 and 342nm in the UV region which are attributed to 4f→5d interconfigurational transitions of Ce³⁺ ions associated with alumina pillars. The O²⁻→Ce³⁺ charge transfer band observed at 263nm for Ce-exchanged and Al–Ce-PM clays is blue shifted by 10nm for Ce–Zr-pillared clays (Ce–Zr-PM) due to fully hydrated Ce³⁺ ions. The Ce³⁺ ions are incorporated in the Al- and Zr-pillars possibly as AlCeO₃ and Ce_xZr_1−xO₂ particles upon heat treatment.