Reduced graphene oxide/SnO2@Au heterostructure for enhanced ammonia gas sensing

[Display omitted] •The RGO/SnO2@Au heterostructure was synthesized by sputtering method and annealing treatment.•The gas response of the heterostructure-based sensor was up to 58% for an NH3 gas concentration of 10 ppm at 25 °C.•The sensing properties were largely attributed to the synergistic effect of the Au@SnO2 and the pn heterostructure. Metal oxide semiconductor gas sensors usually have poor response and recovery properties when operated at room temperature. Reduced graphene oxide (RGO)-based sensors suffer the same issues. Here, we demonstrate the suitability of a RGO/SnO2@Au heterostructure for ammonia (NH3) gas detection. This sensor, which is based on the composite structure, shows high gas sensing properties at room temperature (25 °C). The gas response of the sensor is up to 58% for the NH3 gas concentration of 10 ppm. The response and recovery times are 20 s and 41 s, respectively, both of which are almost 10 times shorter than that of bare RGO or SnO2 for NH3 gas detection. The excellent sensing property is discussed here, and is ascribed to the synergistic effect of the Au@SnO2 and the RGO/SnO2 heterostructure. This work provides a reliable strategy for room temperature gas sensors.