Acidic Site-Assisted Ammonia Sensing of Novel CuSbS2 Quantum Dots/Reduced Graphene Oxide Composites with an Ultralow Detection Limit at Room Temperature

Novel CuSbS2 quantum dots (QDs)/reduced graphene oxide (rGO) composites are self-assembled via a hot-injection method, and CuSbS2 QDs exhibit a near monodispersion on the rGO surface. The gas sensors based on CuSbS2 QDs/rGO composites show the relatively good gas responses toward NH3 with an outstanding detection limit of 500 ppb and an average response time of 50 s at room temperature, and visible light illumination is proven to further promote the sensing performance of the composites. The study of the sensing mechanism reveals that the acidic sites on the surface play an extremely important role in NH3 adsorption of the composites, and the reaction between NH3 molecules and the pre-adsorbed oxygen ions finally leads to the generation of NO molecules. The synergistic effect existing between CuSbS2 QDs and rGO, in terms of electron transfer, is certified as well.