Iron(II) Immobilized within a Metal-Organic Framework Mixed-Matrix Membrane as a H₂O₂ Turn-On Sensor

H₂O₂ detection is closely relevant to human health; however, most of the H₂O₂ probes suffer from low accuracy and sensitivity because of the aggregating nature of solid sensors. In contrast, a mixed-matrix membrane (MMM) with high processability and flexibility is a suitable H₂O₂ probe to overcome these drawbacks. Herein, we fabricated MOF-based MMMs by using a robust UiO-66-(COOH)₂ with carboxylate-chelating moieties, which were utilized for binding Fe (II) metal centers. The Fe (II)-immobilized MOF-MMM involved in a Fenton reaction when treated with H₂O₂, exhibiting a fluorescence turn-on property. Compared to the bulk-state MOF powder, the MOF-MMM sensor showed much-improved sensitivity (detection limit down to 0.0215 μM) because of the uniform dispersion of the probe and a sufficient contact with the analyte. This MOF-MMM sensor combinedly exhibited a turn-on fluorescence response and outstanding sensing properties with flexibility and processability, providing a novel platform suitable for practical sensing applications.