Highly sensitive non-enzymatic glucose sensor based on over-oxidized polypyrrole nanowires modified with Ni(OH)₂ nanoflakes

The electrocatalytic activity of over-oxidized polypyrrole nanowires electrode modified with nickel hydroxide nanoflakes (nf-Ni(OH)₂@oPPyNW) was investigated for its application to an amperometric glucose sensor. The oPPyNW were electrodeposited on graphite electrode by chronoamperometry, and then, Ni(OH)₂ nanoflakes were grown on the oPPyNW by chemical bath method. The surface morphology of the nf-Ni(OH)₂@oPPyNW-modified electrode was characterized by scanning electron microscopy, and its composition was verified by X-ray photoelectron spectroscopy. Following the exploration of optimum deposition conditions, chronoamperometry was used to determine the varying concentrations of glucose in an alkaline solution. The as-prepared nf-Ni(OH)₂@oPPyNW electrode demonstrated excellent performance in terms of electrocatalytic activity, response rate, and stability. It was capable of detecting glucose in a wide dynamic detection range of 0.001-4.863 mM and was able to selectively detect glucose in the presence of several electroactive species such as ascorbic acid, dopamine, l-aspartic acid, and uric acid. At the same time, the proposed electrode exhibited a high sensitivity of 1049.2 μA mM^-1 cm^-2 with a low detection limit of 0.3 μM, illustrating it as a tool in a potential strategy to develop a fast, sensitive, selective, and stable electrochemical sensor for early diabetes diagnosis.