Au/NiO/Multi-Walled Carbon Nanotubes Nanocomposite Electrode for Nitrite Electrochemical Determination

: Gold (Au)/nickel oxide (NiO) nanocomposites were loaded on multi-walled carbon nanotubes (MWC-NTs) utilizing a relatively facile and directly electrochemical deposition method. Transmission electron microscopy (TEM) reveals that the nanocomposites of Au/NiO were successfully covered on the MWCNTs surface. Scanning transmission electron microscopy (STEM) demonstrated the presence of the Au, Ni and O element. The electrochemical performance of the proposed electrode was investigated via cyclic voltammetry (CV) and chronoamperometry. The results showed that Au/NiO/MWCNTs exposed an obvious current response toward nitrite and the anodic peak current varied linearly with nitrite concentration ranging from 0.1 μM to 10 μM (R ═ 0.99865) accompanying with a low detection limit of 0.02 μM. The Au/NiO/MWCNTs electrode also showed great stability and reproducibility for nitrite detection. Moreover, it also displayed good performance for nitrite detection in tap water suggesting its feasibility on specific application.