In situ anchoring Cu nanoclusters on Cu-MOF: A new strategy for a combination of catalysis and fluorescence toward the detection of H2O2 and 2,4-DNP

Establishing a sensing system for detecting various kinds of explosives is of great significance due to the threats they pose to global security. In this work, a novel Cu NCs@Cu-MOF material with a good catalytic property and intense red emission (610 nm) was synthesized by using Cu-MOF as the template and 2,3,5,6-tetrafluorobenzenethiol (TFTP) as the redundant. Benefiting from this in situ strategy, the final product Cu NCs@Cu-MOF preserved the peroxidase-like properties of Cu-MOF, which could efficiently catalyze H2O2 to produce ·OH and then oxidize o-Phenylenediamine (OPD) to its oxidation product (OxOPD) to generate a yellow emission at 560 nm. Furthermore, the strong red fluorescence of Cu NCs@Cu-MOF could be quenched quantitatively with the increase of the concentration of 2,4-dinitrophenol (2,4-DNP) due to the IFE effect. Consequently, with 560 and 610 nm as the response signals, the synthesized material could be employed as H2O2 and 2,4-DNP sensor with the limits of detection (LOD) of 72.5 and 67 nM, respectively. In addition, owning to the difficulty of explosives sampling, a portable sensor was fabricated by using PVA hydrogel as a carrier to load the designed fluorescent material, realizing efficiently sampling of microparticulate from diverse substrates and the on-site sensing.