Highly sensitive and selective carbon dots sensor for hydrogen sulfide based on dual quenching effect

Due to the serious impact of hydrogen sulfide (H 2 S) on the environment and human health, a series of sensors have been increasingly used in industrial production and daily life. In this work, we introduce a novel, to the best of our knowledge, detection method for trace H 2 S in the liquid and gaseous phases based on the dual-quenching mechanism (DQE) of silver ion-doped nitrogen-sulfur co-doped carbon dots (N, S-CDs@Ag + ). Ag + could significantly enhance the fluorescence intensity and detection sensitivity. In the linear detection range of 10–120 nM H 2 S solution, the N, S-CDs@Ag + sensor has a limit of detection (LoD) of 0.83 nM and a response time of 1 min. An enhanced fluorescent sensing film is prepared by assembling N, S-CDs@Ag + on a silica microsphere (SM) microstructured substrate (N, S-CDs@Ag + /SM@PVA) using the layer-by-layer method. In the linear detection range of 1–50 ppm, the film sensor has the advantages of low detection limit (0.41 ppm), fast response time (5 min), stable performance, electromagnetic interference resistance, ease of integration, and in-field detection. It is expected to develop into a compact portable on-site H 2 S trace sensor.