High performance of non-enzymatic glucose biosensors based on the design of microstructure of Ni₂P/Cu₃P nanocomposites

The transition-metal phosphides with metalloid characterics, exhibiting great application potential in the field of glucose detection that plays an important role in the treatment of diabetes, can achieve high sensitivity as a eletrocatalyst for nonenzymatic glucose sensors. However, it has the drawbacks of low detection range and difficulty in manufacture. In this work, a hybrid heterogeneous nanocomposite of copper and nickel phosphide (Ni₂P-Cu₃P) has been designed and successfully prepared by a mild one-step solvothermal method. Inspired by the porous characteristic of sponges, the mesoporous structure with a much larger surface area has been constructed by adjusting the reaction conditions and the element composition of copper and nickel to have more active sites, thus broadening linear range. The precisely designed heterogeneous nanostructure and the unique mesoporous morphology of Ni₂P-Cu₃P were confirmed and characterized by the XRD and TEM analysis. Electrochemical oxidation of glucose on the composite modified glassy-carbon electrode (Ni₂P-Cu₃P/GCE) was measured by chronoamperometry and cyclic voltammetry. At the optimal test potential of + 0.64 V, the Ni₂P-Cu₃P/GCE hybrid electrode possessed an ultra-high sensitive response of 4700 μA mM⁻¹ cm⁻² to glucose, in a broad linear range from 4 μM to 5 mM, and a low detection limit of 0.1 μM at an S/N ratio of 3. The electrode also exhibits excellent anti-interference properties towards other common co-existing electroactive distractions, such as ascorbic acid, uric acid, urea, dopamine, etc.