Humidity and selective oxygen detection by Ag2S nanoparticles gas sensor

Abstract

We report selective oxygen detection by Ag2S nanoparticles gas and humidity sensor at low temperatures with high sensitivity. The Ag2S nanoparticles with preferentially oriented plane (−112) and texture coefficient ~ 1.49 were synthesized by co-precipitation technique. The bandgap and surface area of Ag2S nanoparticles was 2.03 eV and 16.30 m2/g respectively. The response of Ag2S nanoparticles to detect different concentrations of oxygen, LPG, methanol, ethanol and 1-butanol at different temperatures (24–160 °C) was investigated. The Ag2S nanoparticles exhibited a linear relationship between response versus concentration at different temperatures for the tested gases. However, the Ag2S nanoparticles exhibited high response, shortest response/recovery time, good stability and recyclability to oxygen as compared to other tested gases at 160 °C. At room temperature the response of the Ag2S nanoparticles relative humidity (RH) sensor increased linearly with increase in RH. Ag2S nanoparticles as RH sensors also exhibited high response, short response/recovery time, good stability and recyclability.