Enhancing NH3 sensing performance of mixed potential type sensors by chemical exsolution of Ag nanoparticle on AgNbO3 sensing electrode

Abstract

Perovskite oxide based composites have been considered as promising sensing materials due to their superior activity and stability. Herein, we for the first time report a perovskite-type sensing electrode AgNbO3 for solid electrolyte type NH3 sensor, which exhibits well sensing performance to NH3. On this basis, a new strategy is developed for in-situ synthesis of nanoparticle supported AgNbO3 sensing electrode by exsolution process. Well-dispersed Ag nanoparticles are socketed on the surface of AgNbO3 after exsolution treatment at 400 °C. Compared with pristine AgNbO3, the decoration of Ag nanoparticles can further enhance the response signal (electric potential difference, ΔV) of the sensor accompanied by the improved sensitivity and detection limit. More importantly, anti-interference capability of the sensor toward NO and NO2 is effectively enhanced due to the improved adsorption and electro-catalytic activity of the materials. The Ag nanoparticles decorated AgNbO3 sensing electrode with the coordination of superior sensitivity, selectivity and stability can be as a promising sensing electrode candidate for NH3 sensors. In addition, this chemical exsolution process will provide new approach for fabrication of sensing electrode with high performance for gas sensors.