PANI-CNTs Microstructure with Interconnected NiO–NiOOH Particles as Selective Sensing Interface for Methanol Electrochemical Sensor

As outstanding electrocatalytic materials, both metal oxide and conducting polymers have been synergically explored to fabricate electrochemical sensors. A novel electrochemical sensing interface was obtained by electrodeposition of the composite film based on polyaniline (PANI), carbon nanotubes (CNTs) and nickel oxide modified on lab-made screen-printed carbon electrode (SPE) for methanol electrooxidation in alkaline medium. The prepared composite electrode was characterized using various methods, including the Fourier-transform infrared spectroscopy (FT-IR), X-ray Diffraction pattern (XRD), Energy-dispersive X-ray spectroscopy (EDX) and Scanning electron microscope (SEM). The methanol electrochemical oxidation of NiO–NiOOH/PANI-CNTs/SPE in an alkaline medium was studied by using cyclic voltammetry (CV), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS). The obtained excellent sensing parameters including a sensor sensitivity of 8.056 × 10 –5 mA/(mM cm 2 ) with a limit detection LOD of 5 mM (S/N = 3) in wide range of methanol from 30 to 880 mM (R 2 = 0.997) demonstrated that NiO–NiOOH/PANI-CNTs/SPE truly displayed highly electrochemical and catalytic activities for methanol electrooxidation. Furthermore, our proposed SPE sensors exhibited the good stability, repeatability and reproducibility that are crucial for on-site real sample detection and validation.