A facile strategy of using MoS(2) quantum dots for fluorescence-based targeted detection of nitrobenzene

We present a simple approach for producing photoluminescent MoS(2) quantum dots (QDs) using commercial MoS(2) powder as a precursor along with NaOH and isopropanol. The synthesis method is particularly easy and environmentally friendly. The successful intercalation of Na(+) ions into MoS(2) layers and subsequent oxidative cutting reaction leads to the formation of luminescent MoS(2) QDs. The present work, for the first time, shows the formation of MoS(2) QDs without any additional energy source. The as-synthesized MoS(2) QDs were characterized using microscopy and spectroscopy. The QDs have a few layer thicknesses and a narrow size distribution with an average diameter of ∼3.8 nm. Nitrobenzene (NB), an industrial chemical, is both toxic to human health and dangerously explosive. The present MoS(2) QDs can be used as an effective photoluminescent probe, and a new turn-off sensor for NB detection. The selective quenching was operated via multiple mechanisms; electron transfer between the nitro group and MoS(2) QDs through dynamic quenching and the primary inner filter effect (IFE). The quenching has a linear relationship with NB concentrations from 0.5 μM to 11 μM, with a calculated detection limit of 50 nM.