Acidic Sites Assisted Ammonia Sensing of Novel CuSbS2 Quantum Dots/Reduced Graphene Oxide Composites with Ultra-low 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 nearly mono-dispersion on rGO surface. The gas sensors based on CuSbS2 QDs/rGO composites show the relatively good gas responses towards NH3 with an outstanding detection limit of 500 ppb and average response time of 50 seconds at room temperature, and the visible light illumination is proven to further promote the sensing performance of the composites. The study of 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 the electron transfer, is certified as well.