Molecular insights into the sensitivity detection mechanism of fluorescent 2D Zr-BTB for 2,4-dinitrophenol

Detection of nitroaromatic compounds (NACs) has been investigated previously using fluorescent metal-organic frameworks (MOFs). However, the vagueness of the sensing mechanism has hindered the development of efficient sensors. Here we have explored a two-dimensional (2D) MOF, Zr-BTB nanosheets, as a rapid (as short as 10 s), sensitive, and selective sensor for detecting low-concentrations of 2,4-dinitrophenol (2,4-DNP); its limit of detection for 2,4-DNP was quantified to be as low as 0.013 & mu;M (2.40 ppb). The molecular sensing mechanism and the specific interaction sites were investigated using FTIR, UV-vis absorption, XPS, and 2D ssNMR spectroscopy along with density functional theory (DFT) calculations. This work presents insight into florescence-quenching mechanisms for the sensitive sensing of NACs at the molecular level, which may provide valuable ideas for designing novel MOF sensors for NAC detection.