Mesoporous ZnCo2O4 nanowire arrays with oxygen vacancies and N-dopants for significant improvement of non-enzymatic glucose detection

Abstract An efficient electrode for use in a sensitive, nonenzymatic catalyst for electro-oxidation of glucose is urgently needed to reduce the cost of regular diabetic monitoring. Finding a way to improve sensitivity while reserving the catalytic activity for glucose monitoring presents a big challenge. Replacing oxygen defects with nitrogen atoms in a nanostructured transition metal oxide can expose more catalytic active sites with improved electrical conductivity. Herein, a simple and scalable technique has been demonstrated to fabricate N-doped mesoporous ZnCo2O4 nanowire arrays (N-doped ZnCo2O4 electrode) through NH3-plasma treatment toward high-performance nonenzymatic glucose sensors. As a result, an N-doped ZnCo2O4 electrode exhibits ultra-sensitivity of 14,000 μA·mM−1 cm−2, a detection limit of 0.54 μM (S/N = 3), and a short response time of about 7.9 s. The impressive electrocatalytic performance originates from the filling of oxygen vacancies with nitrogen atoms in the mesoporous ZnCo2O4 nanowire arrays, which helps to accelerate the kinetics by increasing the pre-oxidation state of Co3+ and improving the electrical conductivity. Therefore, this study provides new insights into investigating the rational design of nanostructured transition metal oxides/hydroxides with tunable active sites and electrical conductivities for high-performance non-enzymatic glucose sensors.