Ethylenediamine-assisted hydrothermal method to fabricate MoS2 quantum dots in aqueous solution as a fluorescent probe for Fe3+ ion detection

Abstract

Molybdenum disulfide (MoS2) quantum dots (QDs) with unique fluorescence (FL) properties are extensively used for sensors, photoelectrochemical devices, energy storage, and hydrogen evolution. The sufficient demand to develop green and environmentally friendly methods has led to the popularization of MoS2 QD preparation. Here, we provided a proper way to prepare MoS2 QDs by virtue of the ethylenediamine (EN)-assisted exfoliation of MoS2 bulk powder. The whole synthesis process was free of high-toxic agents and carried out in an aqueous solution. The resultant MoS2 QDs presented good dispersion in the aqueous solution and the blue emission at 427 nm. The FL quantum yield of 19% in this work was higher than the yields of most reported MoS2 QDs prepared from their bulk powders. EN was successfully bound to the Mo atom based on the XPS analysis, and the entire S atom was at an oxidation state. Meanwhile, the as-prepared MoS2 QDs possessed high-performance air-stable properties and thus proved to be an effective fluorescent probe for detecting Fe3+ ions with excellent sensitivity, selectivity, and fast response. The limit detection was calculated to be 0.4 μmol/L. The resultant MoS2 QDs can be regarded a potential candidate of fluorescent probe for Fe3+ detection.