Chiral Ni-MOFs as bifunctional electrochemical platform for efficient alcohol oxidation and highly sensitive non-enzymatic glucose detection

Metal-organic frameworks (MOFs) would be as one of the highly promising candidates for the electrocatalytic oxidation of small organic molecules and electrochemical sensing due to their adjustable structures and abundant redox-active sites. The development of new chiral MOFs constructed from chiral ligands and the exploration of their applications in electrocatalysis and electrochemical sensing are still relatively lacking. Herein, three new chiral Ni(II)-MOFs, namely [Ni₂(tda)₂(bib)(H₂O)₄] (CTGU-53), [Ni₂(tda)₂(py)₂] (CTGU-54) and [Ni₂(tda)₂(4,4′-bpy)₂] (CTGU-55) have been prepared with tetrahydrothiazole-2,4-dicarboxylic acid) (H₂tda), Ni(NO₃)₂ and the auxiliary ligands such as 1,1′-benzene-1,4-diylbis (1H-imidazole (bib), pyridine (py) and 4,4′-bipyridine (4,4′-bpy) under solvothermal condition. The electrocatalytic and electrochemical sensing activities towards alcohol oxidation reaction (AOR) and glucose (Glu) detection of these MOFs were systematically investigated. Notably, CTGU-53 exhibits electrocatalytic performance for methanol oxidation (MOR) and ethanol oxidation (EOR), achieving high peak current densities of 31.02 and 31.88 mA·cm⁻², and an excellent mass specific peak current of 219.0 and 225.1 mA·mg⁻¹, respectively. In contrast, CTGU-55 emerges as a superior non-enzymatic glucose sensor, exhibiting remarkable sensitivity of 2066.1 μA·cm⁻²·mM⁻¹, a wide linear range (10−1000 μM), and an ultralow detection limit value (LOD = 0.09 μM, S/N = 3), surpassing most reported MOF-based Glu sensors. CTGU-55 also features a fast response time, excellent selectivity against common interferents, and good cyclic stability. This work highlights chiral Ni-MOFs, particularly CTGU-53 and CTGU-55, as highly efficient electrocatalysts for AOR and ultrasensitive electrochemical probes for glucose monitoring, demonstrating significant potential for practical electrochemical applications.