Active sites tailored rGO-PPy nanosheets with high crystalline tetragonal SnO2 nanocrystals for ammonia e-sensitization at room temperature

Abstract

Hybrid material-based gas sensors are emerging devices in the field of gas sensing. In this present work, we report SnO2 calcinated at two different temperatures (500SnO2 and 600SnO2) and made a composite with reduced graphene oxide (rGO) and polypyrrole (PPy) nanosheets, which resulted in excellent electronic and structural properties that exhibited improved gas sensing performance at the ternary hybrid (rGO-PPy-600SnO2). The physical and chemical properties of the hybrid rGO-PPy-600SnO2 were studied using different techniques such as UV–vis spectroscopy, XRD, FTIR, XPS, SEM, HRTEM, CV, and EIS, as well as the hybrid's sensing performance. The chemo-resistive-type gas sensor was created, and its sensing responses to several gases (NH3, H2, LPG, and CO2) were examined. The findings showed that the ternary hybrid rGO-PPy-600SnO2 had a higher sensing response to NH3 gas than other gases, with the highest sensitivity of 53%, a quick response time of 44 s, and a recovery time of 45 s for 10-ppm ammonia. This enhanced sensing behavior was caused by electronic sensitization between the p-n heterojunctions and can detect up to 4.04 ppm of ammonia at room temperature. The electrode could maintain 88% stability for 50 days. This straightforward and affordable method will be a contender for producing ammonia gas sensors that can function at room temperature.