Highly sensitive sensors based on quasi-2D rGO/SnS2 hybrid for rapid detection of NO2 gas

Nitrogen dioxide (NO2) sensing is important in terms of the agriculture development and healthcare monitoring. However, relatively poor recovery kinetics at a low temperature is still a problem for NO2 sensing and remains to be solved. In this work, we combine the excellent sensing properties and gas adsorption capacity of two- dimensional (2D) tin disulfide (SnS2) hexagonal nanoflakes with the beneficial electrical properties of graphene to build high-performance NO2 sensors by a simple and low-cost method. We found that the sensors based on the quasi-2D rGO-SnS2 hybrids exhibited exclusive selectivity towards NO2. The presence of rGO in hybrids decreased optimal working temperature effectively. Sensors based on 0.8% rGO-SnS2 (G-SS) show almost an order of magnitude increase in response (32) compared to pristine SnS2 (3.5). Especially, the response/recovery time is 50/48 s, respectively, demonstrating the favorable response/recovery kinetics of sensors. Such significant features can be attributed to the synergistic effect of the quasi-2D G-SS hybrid and the local heterojunctions in the interface between SnS2 and rGO.