Fabrication of new nanocomposites based on NiO-MWCNT-sodium dodecyl sulfate in the presence of Gundelia tournefortii extract: application for methanol electrooxidation in alkaline solution.

In this study, new nanocomposites were fabricated based on NiO, multi-walled carbon nanotube (MWCNT), and sodium dodecyl sulfate (SDS). Next, they were characterized using several techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Fourier-transform infrared spectroscopy (FT-IR). The presence of MWCNT and SDS can be applied as adsorption sites for Ni (II) ions. These ions oxidize to NiO nanoparticles (NiO NPs) in the presence of Gundelia tournefortii extract. Then, the electrocatalytic responses of carbon paste electrode (CPE) modified with different modifiers (MWCNT/CPE, NiO/CPE, NiO-MWCNT/CPE, and NiO-MWCNT-SDS/CPE) were recorded in the presence of methanol by cyclic voltammetry. NiO NPs exhibit catalytic properties for electrooxidation of methanol and the presence of MWCNT and SDS promotes current density. The results revealed that NiO-MWCNT-SDS/CPE has a high electrocatalytic activity for methanol electrooxidation. The current density of NiO-MWCNT-SDS/CPE for 0.6 M methanol was 82 mA cm−2 in optimal conditions. According to the chronoamperometric technique, the catalytic rate constant between NiO-MWCNT-SDS and methanol was about 2.6 × 103 cm3 mol−1 s−1. In conclusion, this nanocomposite is a simple, cheap, and efficient catalyst for methanol electrooxidation. [ABSTRACT FROM AUTHOR]