Dye-embedded NanoMOF as a turn-on fluorescent sensor for selective and sensitive detection of hydrogen sulfide

Developing high-performance fluorescent probes for hydrogen sulfide (H2S) has drawn enormous attention recently. In this paper, we report a stable nanoscale dual-emitting probe RB@UiO-66-NO2 for H2S detection, which was obtained by embedding the red-emitting rhodamine B (RB) in the blue-emitting nitryl-functionalized metal-organic framework (MOF) UiO-66-NO2. The accommodated RB is designed as a reference signal, and the nitro groups on the host skeleton can serve as accessible reactive sites to allow for the selective sensing of H2S by RB@UiO-66-NO2. As a result of H2S's ability to dioxide the nitro group on the ligand and improve the intra-molecular charge transfer, RB@UiO-66-NO2 shows enhanced blue fluorescence as well as ratiometric response to H2S. Our investigation shows that RB@UiO-66-NO2 nanoprobe has good stability, fast response (<2 min), distinct color change, and high selectivity and sensitivity (LOD = 5.128 mu M) to H2S in the HEPES solution, demonstrating its potential application for H2S detection under various solution conditions.