High-temperature gas sensors based on proton-conducting ceramic oxides. A brief review

Abstract

Proton-conducting ceramic oxides represent a promising class of materials for a range of high-temperature applications. Their excellent proton transport capabilities rival those of classical oxygen-ionic conductors, offering a basis for the design of protonic ceramic fuel cells (PCFCs) and protonic ceramic electrolysis cells (PCECs) with high performance and efficiency at temperatures ranging from 400 to 700 °C. Nevertheless, proton-conducting ceramic oxides can also be employed as electrolytes for solid-state gas sensors, which are utilized for a variety of analytical purposes, including electrochemical analysis of hydrogen-, ammonia-, oxygen-, or even carbon dioxide-containing gas mixtures. In this review, we present the recent (ten-year) achievements in the R&D field of electrochemical solid-state sensors based on proton-conducting ceramic electrolytes. Along with discussion of their operation principles, the specific functions (sensitivity, response time, selectivity) are analyzed in detail. This work therefore represents a concise overview of the application of proton-conducting electrolyte materials for in-situ electrochemical analysis provided at elevated temperatures.