Wu Yang

Schematic representation of the preparation process of A-COF@NH ₂ -MWCNT/GCE and its sensing principle towards rutin.

Glutathione (GSH) serves as the core antioxidant within cells, and its highly sensitive and selective detection is of great significance for disease diagnosis and research on redox regulation.

Metal–organic framework (MOF) derivatives used as supercapacitor electrode materials generally suffer from poor intrinsic conductivity and inadequate capacitive performance, so, it is crucial to enhance their electrochemical performance through rational nanoscale design. In this study, nanoscale structure engineering is exploited to construct a hollow nanostructure with tailored morphology and optimized electronic properties. A hollow structure was first constructed via Ni(NO3)2 and Co(NO3)2 etching MIL101(Fe) as a template. Finally, combining molybdate ion intercalation and selenization treatment, the multimetal selenide materials (hereinafter referred to FNCLM/S) were successfully synthesized. The synergy between the intercalation and selenization is systematically optimized to simultaneously modulate the electronic structure, interlayer environment, and morphology of the resulting material, thereby significantly enhancing the electrochemical kinetics. Owing to the short ion transport paths provided by the hollow structure, the electrolyte penetration facilitated by the loose particle packing structure, and synergistic effects among the multimetal components, the prepared FNCLM-0.5/S-500 ((Fe, Ni, Co)Se/MoSe2) electrode exhibited an excellent specific capacitance of 2368.99 F·g–1 at a current density of 1 A·g–1 in a three-electrode system. A hybrid supercapacitor assembled with this material as the cathode and activated carbon as the anode can operate stably over a wide voltage window of 1.53 V. It achieved an energy density of up to 100.34 Wh·kg–1 at a power density of 764.98 W·kg–1, with a capacity retention rate of 75% and a Coulombic efficiency approaching 100% after 6,000 charge–discharge cycles. Furthermore, the device successfully powered a commercial timer for nearly 20 min, demonstrating excellent potential for practical applications. This work offers a feasible intercalation–selenization combined strategy for MOF-derived multimetal material preparation toward high-performance hybrid supercapacitors.

A dual-mode sensor, Cu NCs/Eu³⁺@UiO-66-(COOH)₂, was constructed by co-functionalizing UiO-66-(COOH)₂ with copper nanoclusters and Eu³⁺ ions. Upon exposure to H₂O₂, the fluorescence of Cu NCs at 464 nm enhanced while Eu³⁺ emission at 616 nm was quenched, enabling ratiometric fluorescence detection with a limit of detection (LOD) of 0.035 µM. Leveraging the peroxidase-like activity of Cu NCs, the probe material catalyzes the oxidation of a chromogenic substrate 3,3’,5,5’-tetramethylbenzidine (TMB) by H₂O₂ to produce a visible color change, enabling a sensitive colorimetric analysis of H₂O₂ with a LOD of 0.021 µM and its rapid and visual detection with the help of smartphone. The system was applied to detect H₂O₂ in real samples with satisfactory recoveries. Graphical abstract

Nitrofurazone, a commonly used nitrofuran antibiotic, is widely applied in antimicrobial therapy as well as in aquaculture and livestock farming. However, its residues can pose risks to human health and cause environmental pollution. Therefore, the development of a highly sensitive detection method for nitrofurazone is of great significance. In this study, a novel core-shell composite material, UiO@TATF COF, was prepared by in situ growing TATF COF on the UiO-66-NH₂ surface through a Schiff-base reaction using 4,4',4″-(1,3,5-triazine-2,4,6-triyl) tris(benzaldehyde) (TFPT) and 1,3,5-tris(4-aminophenyl) benzene (TAPB) as monomers. Subsequently, by further introducing the conductive material carbon black (CB), a novel electrochemical sensor UiO@TATF COF/CB/GCE was successfully constructed. Covalently linked UiO@TATF COF achieves a robust core-shell interface and possesses a large specific surface area and abundant active functional groups. The resultant sensor system exhibits clear synergistic effects, enabling electrocatalysis and sensitive detection toward nitrofurazone in food, environmental, and ointment samples with a detection limit of 0.05 µM (S/N = 3).