Impedance spectroscopy on pH-sensors with lithium lanthanum titanate sensitive material

被引：30

作者：

Bohnke, C ^{[1
]}

Fourquet, JL ^{[1
]}

机构：

[1] Univ Maine, UMR 6010 CNRS, Fac Sci & Tech, Lab Fluorures, F-72085 Le Mans, France

来源：

ELECTROCHIMICA ACTA | 2003年 / 48卷 / 13期

关键词：

pH-sensor; lithium lanthanum titanate; perovskite; complex impedance spectroscopy;

D O I：

10.1016/S0013-4686(03)00260-3

中图分类号：

O646 [电化学、电解、磁化学];

学科分类号：

081704 ;

摘要：

The ceramic Li3xLa2/3-x,1/3-2xTiO3 is used, in an all-solid-state configuration, as pH-sensor in aqueous buffer solution. This ceramic displays a pH sensitivity comparable to the one obtained with a commercial glass electrode and does not show any sensitivity to the redox potential of the solution. This is one of the remarkable properties of this ceramic pH-sensor. It is shown in this paper that the reproducibility and the behaviour of the pH-response depend on the morphology of the grain boundaries particularly on the size of the grains. A so-called 'good' pH-response is obtained with a ceramic showing big and homogeneous grains. Complex impedance spectroscopy reveals that such ceramic has a high grain boundary resistance. Furthermore, this electrochemical technique allows us to determine that the interface reaction involved in the pH detection has a time constant of the order of the second. Several assumptions such as ion exchange or acid-base reaction are proposed to explain the sensitivity of the ceramic material to the pH of the solution. (C) 2003 Elsevier Science Ltd. All rights reserved.

引用

页码：1869 / 1878

页数：10

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