The preparation of NiO/Ni-N/C nanocomposites and its electrocatalytic performance for methanol oxidation reaction

Direct methanol fuel cells (DMFCs) have been extensively studied in developing a new non-precious metal catalyst to replace commercial platinum catalysts, due to its expensive cost and easy to CO poisoning. In this work, nickel oxide/nickel supported by N-doped carbon nanocomposites (NiO/Ni-N/C) were prepared through hydrothermal method and further carbonization at different temperature. The surface morphology and composition of the NiO/Ni-N/C nanocomposites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectra (XPS). Through electrochemical experiments, the NiO/Ni-N/C nanocomposites modified glassy carbon electrode (NiO/Ni-N/C/GCE) exhibits highly electrocatalytic activity to methanol oxidation reaction (MOR) in alkaline solution. Among them, the NiO/Ni-N/C carbonization at 500 ℃ (NiO/Ni-N/C500) displays the highest mass activity (1043 mA·mgNi-1) at 0.73 V (vs Ag/AgCl), which much higher than that of the Ni(OH)2/N-C and the NiO/Ni-N/C carbonization at other temperature (400, 600, 700 ℃). In addition, the catalytic activity of the NiO/Ni-N/C500 is 2.12 times that of the commercial Pt/C. The NiO/Ni-N/C500/GCE also possesses fast kinetics, excellent stability and CO tolerance. Therefore, the NiO/Ni-N/C500 nanocomposites have great application potential as MOR catalyst.