Growth of Bimetallic Oxide Nanoarray on Nickel Foam as an Efficient Binder-Free Electrode for Nitrite Electrochemical Sensing

A large number of various organic and inorganic pollutants are produced each day around the globe to lead to the problem of environmental pollution. Excess nitrite remains in the agricultural fields and foods to enter the environment, rendering it one type of typical environmental pollutant. Therefore, a simple, accurate, quick and low-cost sensor to detect nitrite is highly necessary and meaningful for public health and environmental security. In this study, bimetallic transition metal oxide nanoarray materials have been directly grown on nickel foam (NF) to afford a binder-free electrochemical sensor of Co₁Ni₁O/NF to determine nitrite in an amperometric mode. Unique radial needle-like nanoarray morphology was observed for the as-prepared Co₁Ni₁O, which was believed to offer a sufficient conductive pathway for facile electron transfer to enable quick nitrite electro-oxidation. The synergistic effect of the bimetallic Co–Ni oxide nanoarray materials of the binder-free electrochemical sensor rendered a wide linear range of 10 μM to 3.5 mM for nitrite detection, with excellent anti-interference, reproducibility and stability. The Co₁Ni₁O/NF also exhibited good recovery in actual lake water samples, which would be promising for its potential application under the real scenarios.