Room-temperature synthesis of CuO/reduced graphene oxide nanohybrids for high-performance NO2 gas sensor

We report the room-temperature synthesis of CuO/reduced graphene oxide (CuO/rGO) nanohybrids via a one-pot solution process, in which the reduction of GO and the formation of CuO were completed simultaneously at room temperature. The as-prepared sheet-like CuO with hundreds nanometer in sizes are well-mixed together uniformly with rGO in the nanohybrids. The gas sensors based on the as-prepared CuO/rGO nanohybrids were fabricated and used to detect low-concentration NO2 gas (1-75 ppm) with excellent selectivity. Upon exposure to 1 ppm NO2 at room temperature, the as-prepared CuO/rGO nanohybrids display a sensitive response of about 14 and the reponse time and recovery time are about 66 and 34 s, respectively. The low detection limit is evaluated to be as low as 60 ppb at room temperature. The high sensing response can be attributed to the large surface area of CuO/rGO nanohybrids and enhanced carrier transfer between NO2 molecules and nanohybrids. We believe that this low-cost strategy provides a facile route to prepare other rGO-based nanohybrids for nanosensors.