Benzimidazole-Regulated 1D 4-Fluorosalicylic Acid MOF Composite Material Design and Its Application in Glucose Sensing.

Metal-organic frameworks (MOFs) have significant potential in electrochemical sensors, but the guest molecules and residual solvents in the pores often block the active sites and limit the reaction kinetics. One-dimensional nanostructures can provide direct conduction pathways and shorten ion diffusion distances, thereby enhancing electron transport and electrode contact. Meanwhile, fluorine-incorporated MOF materials leverage the high electronegativity of fluorine to substitute oxygen, suppress oxidation to widen the voltage window, and improve stability through enhanced hydrophobicity. In this work, 4-fluorosalicylic acid (4FSA) was used as the ligand and benzimidazole (Bim) was introduced to adjust the coordination environment, and one-dimensional Bim4FSA-MOF nanorods were successfully constructed. While the guest molecules were largely removed, the nickel sites were thereby activated and the pore size was enlarged. Due to the synergistic effect of one-dimensional nanostructure-promoted electron transport and the Ni(OH)2/NiOOH dynamic active center, the B-250 composite exhibited excellent performance in a glucose electrochemical sensor. The optimized sensor delivered a detection limit of 0.022 μM and a detection time of 0.9 s, along with a sensitivity value of 2986.45 μA mM-1 cm-2, which provides a new strategy for the design of efficient MOF-based electrochemical sensor interface.