Aerosol-assisted nanostructuring of nickel/cobalt oxide thin films for viable electrochemical hydrazine sensing

Herein, we report the fabrication of NiO-CoO films for the electrochemical detection of hydrazine. An electrochemical sensor was devised where aerosol assisted chemical vapor deposition (AACVD) was employed as a nifty method for synthesizing NiO-CoO films over FTO electrodes. NiO-CoO-nanoparticle (NP) and NiO-CoO-nanowall (NW) films were fabricated over FTO substrates. The electrocatalytic analysis was performed in a standard three-electrode electrochemical setup. NiO-CoO-NW/FTO showed enhanced electro-oxidation for hydrazine at all concentrations tested. XRD, XPS, EDX, and FE-SEM techniques were used to characterize the structural, morphological, and elemental properties of NiO-CoO films. The results showed improved sensitivity, a large dynamic range, and good long-term stability of NiO-CoO-NW films. The amperometric response was used to measure the detection limit, and it was as low as 0.01 μM, and the sensitivity is ∼33 μA μM-1 cm-2. Besides, the NiO-CoO-NW/FTO electrodes showed significant selectivity towards hydrazine upon testing cross-sensitivity to other common interfering molecules. This strategy of using NiO-CoO-NW/FTO electrodes prepared via AACVD has great potential for the direct determination of hydrazine in environmental sensing applications.