A Novel Turn-On Fluorescent Sensor Based on Sulfur Quantum Dots and MnO 2 Nanosheet Architectures for Detection of Hydrazine.

In this paper, the SQDs@MnO 2 NS as the probe was applied to construct a novel "turn-on" fluorescent sensor for sensitive and selective detection of hydrazine (N 2 H 4 ). Sulfur quantum dots (SQDs) and MnO 2 nanosheets (MnO 2 NS) were simply mixed, through the process of adsorption to prepare the architectures of SQDs@MnO 2 NS. The fluorescent emissions of SQDs@MnO 2 NS play a key role to indicate the state of the sensor. According to the inner filter effect (IFE) mechanism, the state of the sensor at the "off" position, or low emission, under the presence of MnO 2 NS, is which the ultraviolet and visible spectrum overlaps with the fluorescence emission spectrum of SQDs. Under the optimal conditions, the emission was gradually recovered with the addition of the N 2 H 4 , since the N 2 H 4 as a strong reductant could make the MnO 2 NS converted into Mn 2+ , the state of the sensor at the "on". Meanwhile, the fluorescent sensor possesses good selectivity and high sensitivity, and the detection concentration of N 2 H 4 with a wide range from 0.1 µM to 10 mM with a detection limit of 0.072 µM. Furthermore, actual samples were successful in detecting certain implications, indicating that the fluorescent sensor possesses the potential application ability to monitor the N 2 H 4 in the water.