Layered coordination polymer nanoflakes of copper tetracyanonickelate: Efficient electrocatalyst for high-performance...

Layered coordination polymer nanoflakes of copper tetracyanonickelate CuNi(CN)₄ were synthesized as a bimetal nanocomposite by a facile co-precipitation technique at room temperature and applied to electrochemical glucose sensing, demonstrating strong potential as a non-enzymatic electrode material. The integration of Cu and Ni centers within a cyanide-bridged Prussian blue-type framework afforded abundant redox-active sites and a high surface area, facilitating efficient electron transfer and enhanced catalytic activity. Electrochemical analyses, including cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and chronoamperometry (CA), confirmed the electrode's strong electrocatalytic response toward glucose oxidation. The CuNi(CN)₄-modified electrode exhibited remarkable sensitivity, recording a response of 1151.48 μA mM^-1 cm^-2 in CV along with a detection limit of 0.35 μM. In CA analysis, an even greater sensitivity of 1796.53 μA mM^-1 cm^-2 was achieved across a glucose concentration range 0.1-12 mM, accompanied by excellent linearity (R² = 0.9989). Moreover, the sensor exhibited a rapid response, strong anti-interference capability, and operational stability maintained over 16 days. Practical applicability was validated through glucose quantification in commercial beverages, including black tea, Pepsi, and Sprite, yielding recoveries of 95.92%-103.52%, with RSD values consistently below 1.625%. These findings demonstrate the CuNi(CN)₄ nanocomposite's promise as a reliable and high-performance platform for real-time glucose monitoring in food diagnostics.