Facile synthesis of 2D/3D hierarchical NiCu bimetallic MOF for non-enzymatic glucose sensor

The development of transition metal based enzyme-free glucose (Glu) sensor with high sensitivity, wide linear range, and long-term stability is highly desired. Herein, a series of 2D/3D hierarchical structured bimetallic organic framework (NiCu-MOF-x, x = 2, 4, 6, 8) were developed through a one-step hydrothermal route by adjusting the ratio of nickel and copper salts. The morphological similarity of NiCu-MOF-x and Ni-MOF was evidenced by X-ray diffraction survey. The structural evolution of NiCu-MOF-x was revealed by scanning electron microscopy. The optimal NiCu-MOF-6 exhibits high electrocatalytic activity toward Glu oxidation. Being applied as the electrode modifier for glassy carbon electrode (GCE), NiCu-MOF-6/GCE exhibits a remarkably widened linear range than its monometallic analog, owing to its significantly increased electrochemical surface area, interconnected channels for mass/electron transfer and synergistically functionalized Ni/Cu electroactive sites. Being applied in human serum analysis, this sensor shows a good feasibility with satisfying recoveries.