Comparison of pH sensitivity of lithium lanthanum titanate obtained by sol脙脙脙脙脙脙gel synthesis and solid state chemistry

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• 作者：Bohnke ; Cl. ; Regrag ; B. ; Le Berre ; F. ; Fourquet ; J.-L. ; Randrianantoandro ; N.
• 关键词：pH sensors ; Perovskite ; Lithium solid electrolyte ; Sol脙脙脙脙脙脙gel synthesis
• 刊名：Solid State Ionics
• 出版年：2005
• 期刊代码：96_01672738
• 类别：ch
• 出版时间：January 14, 2005
• 卷：176
• 期：1-2
• 页码：73-80
• 文件大小：668 K

摘要

The use of the high lithium-conductive perovskite compound Li_3xLa_{2/3芒芒芒x 1/3芒芒芒x}TiO₃ for the detection of H⁺ species in aqueous solution was investigated. The compound was synthetized by the sol芒芒芒gel route and heat treatments at temperature between 800 and 1200 芒芒C. LLTO was obtained with an impurity : La₂Ti₂O₇ in low proportions at 1200 芒芒C. After sintering, the ceramics were used in a pH sensitive electrode and studied by Scanning Electron Microscopy. A variation of potential in different pH-buffers was obtained with a response maximum of 28 mV/pH unit at 25 芒芒C and 34 mV/pH unit at 60 芒芒C for the better responding electrode. The response is poor for material obtained at 800 and 1000 芒芒C. A comparison with the properties of the same material obtained by solid state reaction and after ball-milling and sintering is shown. The membrane configuration proves the ability of this perovskite to detect the variation of pH between 2 and 10. The response is not Nernstian but the sensitivity and the response time are good. The origin of the detection seems linked to a surface reaction. The detection inhibited when the electrodes are stocked in air can be retrieved by heating at temperatures higher than 40 芒芒C in buffer solutions.