Three-Dimensional MoS2/Reduced Graphene Oxide Nanosheets/Graphene Quantum Dots Hybrids for High-Performance Room-Temperature NO2 Gas Sensors

Abstract

This study presents three-dimensional (3D) MoS2/reduced graphene oxide (rGO)/graphene quantum dots (GQDs) hybrids with improved gas sensing performance for NO2 sensors. GQDs were introduced to prevent the agglomeration of nanosheets during mixing of rGO and MoS2. The resultant MoS2/rGO/GQDs hybrids exhibit a well-defined 3D nanostructure, with a firm connection among components. The prepared MoS2/rGO/GQDs-based sensor exhibits a response of 23.2% toward 50 ppm NO2 at room temperature. Furthermore, when exposed to NO2 gas with a concentration as low as 5 ppm, the prepared sensor retains a response of 15.2%. Compared with the MoS2/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 NO2 gas, respectively. Additionally, the MoS2/rGO/GQDs-based sensor exhibits outstanding repeatability and gas selectivity. When exposed to certain typical interference gases, the MoS2/rGO/GQDs-based sensor has over 10 times higher sensitivity toward NO2 than the other gases. This study indicates that MoS2/rGO/GQDs hybrids are potential candidates for the development of NO2 sensors with excellent gas sensitivity.