High-Surface-Area Nanocrystalline Cerium Phosphate through Aqueous Sol-Gel Route

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• 作者：K. Rajesh ; P. Mukundan ; P. Krishna Pillai ; V. R. Nair ; and K. G. K. Warrier
• 刊名：Chemistry of Materials
• 出版年：2004
• 出版时间：July 13, 2004
• 年：2004
• 卷：16
• 期：14
• 页码：2700 - 2705
• 全文大小：222K
• 年卷期：v.16,no.14(July 13, 2004)
• ISSN：1520-5002

文摘

Rare earth phosphates have recently been investigated as a potential ceramic material inview of their high-temperature phase stability, high melting point, low thermal conductivity,optical, fluorescence, and catalytic properties, and layered structural features. The presentwork describes a method for synthesizing nanocrystalline cerium phosphate starting fromcerium nitrate and orthophosphoric acid by sol-gel process involving controlled precipitationfollowed by electrostatic stabilization (peptization) using nitric acid and deagglomeration ofsol particles using ultrasonication. Average particle size of cerium phosphate in the precursorsol is 50 nm. Dehydroxylation of the precursor gel was studied by thermal analysis andFTIR spectrum. The transformation of low-temperature rhabdophane phase to hexagonaland further to monoclinic monazite type at 800 ges/entities/deg.gif">C is evidenced from the XRD pattern. Ceriumphosphate had crystallite size of 10 nm and excellent thermal phase stability up to 1700 ges/entities/deg.gif">Cas observed from XRD data. Specific surface area of 98 m²/g was obtained for precursor gelcalcined at 400 ges/entities/deg.gif">C. The nanosize cerium phosphate has been sintered at 1300 ges/entities/deg.gif">C to ~99%density with an average grain size of 1 ges/entities/mgr.gif">m as observed from SEM micrographs.