Lewis acidic Fe3+-driven catalytic active Ni3+ formation in Fe-free metal–organic framework for enhanced electrochemical glucose sensing.

[Display omitted] Manipulating metal valence states and porosity in the metal–organic framework (MOF) by alloying has been a unique tool for creating high-valent metal sites and pore environments in a structure that are inaccessible by other methods, favorable for accelerating the catalytic activity towards sensing applications. Herein, we report Fe3+-driven formation of catalytic active Ni3+ species in the amine-crafted benzene-dicarboxylate (BDC-NH 2)-based MOF as a high-performance electrocatalyst for glucose sensing. This work took the benefit of different bonding stability between BDC-NH 2 ligand, and Fe3+ and Ni2+ metal precursor ions in the heterometallic Ni x Fe (1- x) -BDC-NH 2 MOF. The FeCl 3 that interacts weakly with ligand, oxidizes the Ni2+ precursor to Ni3+-based MOF owing to its Lewis acidic behavior and was subsequently removed from the structure supported by Ni atoms, during solvothermal synthesis. This enables to create mesopores within a highly stable Ni-MOF structure with optimal feed composition of Ni 0.7 Fe 0.3 -BDC-NH 2. The Ni3+-based Ni 0.7 Fe 0.3 -BDC-NH 2 demonstrates superior catalytic properties towards glucose sensing with a high sensitivity of 13,435 µA mM−1 cm−2 compared to the parent Ni2+-based Ni-BDC-NH 2 (10897 μA mM−1 cm−2), along with low detection limit (0.9 μM), short response time (≤5 s), excellent selectivity, and higher stability. This presented approach for fabricating high-valent nickel species, with a controlled quantity of Fe3+ integrated into the structure allowing pore engineering of MOFs, opens new avenues for designing high-performing MOF catalysts with porous framework for sensing applications. [ABSTRACT FROM AUTHOR]