Pd-based ternary alloys used for gas sensing applications: A review

Abstract

Pd-based sensors are important gas sensing materials and possess a significant potential to improve many other engineering systems. Several Pd-based single and binary alloy systems have been reported in the past few decades. Some ternary additions of transition elements in the binary systems have been successfully added recently to further improve various aspects of sensitivity, response and mechanical stability of Pd-based sensors. Ternary alloys have shown promising mechanical stability and sensing behavior towards gas sensing behavior and are potential candidate materials for next-generation gas sensors. In addition, it is expected that a ternary alloy system possesses significant tolerance towards toxic H2S gases, especially for the chemical and food industries applications. However, it is inherited with a problem of surface segregation which must be improved further. Various research activities are in the emerging phase and need further improvement towards ternary alloy systems. In the present work, a comprehensive review of the various Pd-based ternary system is presented in terms of sensing behavior, segregation phenomena, microstructural features, mechanical stability, and the important factors to improve the sensing performance of these alloys. Various factors that control these sensing alloys are also summarized as a future reference guide in this field.