Regulation of NiCo-MOF morphology by bimetallic ratio for high-performance detection of glucose

Bimetallic NiCo-MOFs were synthesized via a solvothermal method, possessing optimized morphology and more exposure of active sites. • Nickel-cobalt synergism endows NiCo-MOFs with superior glucose sensing performance compared with monometallic Ni-MOF. • The bimetallic NiCo 3 -MOF demonstrates exceptionally high sensitivity and a rapid response for glucose detection. By multi-metal doping method, the morphology of metal-organic frameworks (MOFs) could be regulated, leading to more exposed active sites and enhanced mass transfer for electrolyte, thereby significantly improving the electrocatalytic oxidation capacity of MOFs toward glucose molecules. This strategy offers a novel approach for designing high-performance nickel-based MOF non-enzymatic electrochemical glucose sensors. In this study, a series of bimetallic NiCo-MOFs were successfully synthesized via a one-pot solvothermal method, and the influence of varying metal ratios on sensor performance was systematically investigated. Electrochemical results demonstrate that bimetallic NiCo-MOFs exhibit superior catalytic activity compared with monometallic Ni-MOF. Among bimetallic NiCo-MOFs, NiCo 3 -MOF (Ni:Co = 1:3) displays the most outstanding sensing performance, achieving high sensitivities of 2048.55 μA·mM −1 ·cm −2 and 966.45 μA·mM −1 ·cm −2 in the linear ranges of 0–600 μM and 600–3000 μM, respectively. The detection limit (LOD, S/N = 3) is as low as 0.57 μM, with a rapid response time of only 1.8 s. In contrast, the monometallic Ni-MOF exhibits significantly lower sensitivities of 584.15 μA·mM −1 ·cm −2 and 414.58 μA·mM −1 ·cm −2 under identical conditions. This enhanced electrochemical performance is attributed to the synergic effect between cobalt and nickel active sites in MOFs and nanosheet-like architecture, resulting in increasing of the specific surface area and exposing more accessible active sites. Furthermore, bimetallic NiCo 3 -MOF demonstrates excellent current stability over a prolonged period of 3000 s. Selectivity tests confirm its strong resistance to common interfering species such as sodium chloride, potassium chloride, sucrose, lactose, uric acid, dopamine hydrochloride, and ascorbic acid, while reliable detection performance is maintained in bovine serum albumin samples. Therefore, bimetallic NiCo 3 -MOF holds significant promise for application in MOF-based electrochemical biosensors. Download: Download high-res image (65KB) Download: Download full-size image