Three-Dimensional MoS(2)/Reduced Graphene Oxide Nanosheets/Graphene Quantum Dots Hybrids for High-Performance Room-Temperature NO(2) Gas Sensors

This study presents three-dimensional (3D) MoS(2)/reduced graphene oxide (rGO)/graphene quantum dots (GQDs) hybrids with improved gas sensing performance for NO(2) sensors. GQDs were introduced to prevent the agglomeration of nanosheets during mixing of rGO and MoS(2). The resultant MoS(2)/rGO/GQDs hybrids exhibit a well-defined 3D nanostructure, with a firm connection among components. The prepared MoS(2)/rGO/GQDs-based sensor exhibits a response of 23.2% toward 50 ppm NO(2) at room temperature. Furthermore, when exposed to NO(2) gas with a concentration as low as 5 ppm, the prepared sensor retains a response of 15.2%. Compared with the MoS(2)/rGO nanocomposites, the addition of GQDs improves the sensitivity to 21.1% and 23.2% when the sensor is exposed to 30 and 50 ppm NO(2) gas, respectively. Additionally, the MoS(2)/rGO/GQDs-based sensor exhibits outstanding repeatability and gas selectivity. When exposed to certain typical interference gases, the MoS(2)/rGO/GQDs-based sensor has over 10 times higher sensitivity toward NO(2) than the other gases. This study indicates that MoS(2)/rGO/GQDs hybrids are potential candidates for the development of NO(2) sensors with excellent gas sensitivity.