A novel mixed-potential type NH3 sensor based on Ag nanoparticles decorated AgNbO3 sensing electrode synthesized by demixing method

Abstract

Solid-electrolyte type sensors based on composite sensing electrodes (SE) have attracted extensive attention due to their excellent sensitivity and anti-interference property. Herein, we prepare AgNbO3/Ag (ANO/Ag) composite SE for the solid-electrolyte type NH3 sensor using a facile demixing method. Compared with pristine ANO-SE, the sensor based on ANO/Ag-SE exhibits larger response signal, higher sensitivity and lower detection limits. What’s more, the anti-interference capability of the sensor toward NOx is effectively enhanced. The effect of the molar ratio of Ag to Nb on the performance of the sensor is also investigated. When the molar ratio of Ag:Nb is 1.05:1, the sensor exhibits largest response signals and sensitivity (−91.2 mV/decade) to NH3. In the meantime, the response signal of the sensor to a fixed NH3 concentration almost keeps constant under different relative humidity (RH) and oxygen concentrations. Thus, the demixing method will provide a new approach for the fabrication of composites SEs with high performance for gas sensors.