Ultrathin layered MoS2/N-doped graphene quantum dots (NGQDs) heterostructures for highly sensitive room temperature NO2 gas sensor

Due to high surface-to-volume ratio, stability, and more active sites, molybdenum disulfide (MoS2) has been attracted as a promising gas-sensing material. However, the room temperature (RT- 30 ℃) MoS2-based gas sensors still suffer slow response, recovery rates, and less sensitivity, notably for NO2. Herewith, we synthesized a novel molybdenum disulfide/nitrogen-doped graphene quantum dot (MoS2/NGQD) heterostructure via hydrothermal method for NO2 detection. The MNG-3 heterostructure is endowed with enhanced response of 82.4% towards 50 ppm of NO2 at 30 ℃, which is 6.5 folds greater than that of pristine MoS2 nanosheets (NSs). MNG-3 samples outperform with a quick recovery (30 s), excellent repeatability (5 cycles), long-term stability (5 weeks), and good selectivity towards 30 ℃ NO2 detection concentration of 50 ppm. The unique 2D/0D heterostructures and synergistic effect of NGQD and MoS2 NSs are responsible for the improved sensing performance. It undoubtedly suggests the feasible nature of prepared MoS2/NGQD heterostructures for 30 ℃ NO2 detection.