Surfactant-Assisted Electrodeposition of Nickel Nanostructures and Their Electrocatalytic Activities Toward Oxidation of Sodium Borohydride, Ethanol, and Methanol

Different Ni nanostructures were electrodeposited from the Watts bath in the presence of different concentrations of sodium dodecyl sulfate (SDS) using the pulse reverse current technique on the copper substrate. The concentration of SDS was lower than the critical micelle concentration (CMC), equal to CMC and higher than CMC for electrodeposition of Ni-1, Ni-2, and Ni-3 samples respectively. The electrodeposited samples were characterized by X-ray diffraction (XRD), atomic force microscopy (AFM), and field emission-scanning electron microscopy (FE-SEM) techniques. The electrocatalytic activity of samples for oxidation of sodium borohydride, ethanol, and methanol was investigated using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). For borohydride oxidation, one oxidation peak, as well as one semicircle, observed respectively in the cyclic voltammograms and Nyquist diagrams confirmed that only one reaction happened on the surface of samples. It was observed that at high overpotentials, Ni-1 sample was more reactive for NaBH4 oxidation compared to the Ni-2 and Ni-3 samples.