Preparation and characterization of the electroactive composites containing nickel nanoparticles and carbon nanotubes

The composites containing Ni nanoparticles and N-doped carbon nanotubes were prepared using Ni–Al layered double hydroxides (LDHs) with various Ni/Al atomic ratios (2 and 3) and acetonitrile via catalytic chemical vapor deposition at 600, 700 and 800 °C. Powder X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, thermogravimetric analysis and nitrogen sorption were employed to characterize their physicochemical properties. The electrochemical properties of the composites were evaluated by means of cyclic voltammetry in alkaline medium with the addition of methanol as a probe molecule.Application of different synthesis temperatures and Ni–Al LDHs with various Ni concentrations influenced the electrocatalytic performance of the composites for the methanol oxidation reaction as it affected the dispersion of Ni nanoparticles and electrode/electrolyte interfacial active area. The hybrid material prepared at the lowest temperature (600 °C) and derived from LDHs with a lower Ni/Al = 2 appeared to have the best electrochemical properties among the studied composites.

► LDHs are successfully used for the preparation of the electroactive composites. ► Synthesis temperature affects Ni nanoparticle size and graphitization degree. ► N-doped multiwalled carbon nanotubes are grown on metallic nickel at 600–800 °C. ► Newly prepared electrode materials are active in the methanol oxidation reaction.