KINETICS OF OXYGEN INTERACTION WITH PT/CEO2 SENSORS - APPLICATION OF A NEW PRESSURE MODULATION SPECTROSCOPY

被引：7

作者：

DUBBE, A

WIEMHOFER, HD

SCHIERBAUM, KD

GOPEL, W

机构：

[1] Institute of Physical and Theoretical Chemistry, University of Tübingen, D-7400 Tübingen

来源：

SENSORS AND ACTUATORS B-CHEMICAL | 1991年 / 4卷 / 1-2期

关键词：

D O I：

10.1016/0925-4005(91)80173-H

中图分类号：

O65 [分析化学];

学科分类号：

070302 ; 081704 ;

摘要：

Improvements in the low-temperature response of solid-state electrochemical gas sensors are highly desirable. These require a detailed understanding of the frequency-dependent gas-specific time constants involved in gas diffusion, surface diffusion, surface and interface reactions. In this context, we have developed a new method to characterize the dynamic response of the electrode potential upon sinusoidal oxygen partial-pressure variations (pressure modulation spectroscopy, PS). The frequency-dependent response functions and corresponding results from classical electrochemical impedance spectroscopy (EIS) make it possible to derive theoretical models which describe transport processes in porous gas electrodes at the three-phase boundaries. After a brief presentation of the principle, its powerful application is demonstrated in a study of the kinetics of different Pt electrodes on CaO-doped CeO2 electrolytes. Surface diffusion effects play a central role in the overall kinetics of the O2 response of their microstructures. Gradients of the oxygen surface concentration are analysed in an independent spectroscopic study on well-characterized CeO2 samples with Pt contacts.

引用

页码：23 / 28

页数：6