A Novel Turn-On Fluorescent Sensor Based on Sulfur Quantum Dots and MnO₂ Nanosheet Architectures for Detection of...

In this paper, the SQDs@MnO₂ NS as the probe was applied to construct a novel "turn-on" fluorescent sensor for sensitive and selective detection of hydrazine (N₂H₄). Sulfur quantum dots (SQDs) and MnO₂ nanosheets (MnO₂ NS) were simply mixed, through the process of adsorption to prepare the architectures of SQDs@MnO₂ NS. The fluorescent emissions of SQDs@MnO₂ 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 MnO₂ 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 N₂H₄, since the N₂H₄ as a strong reductant could make the MnO₂ NS converted into Mn²⁺, the state of the sensor at the "on". Meanwhile, the fluorescent sensor possesses good selectivity and high sensitivity, and the detection concentration of N₂H₄ 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 N₂H₄ in the water.