NiW/TiOx composite layers as cathode material for hydrogen evolution reaction

NiW + TiOx composite layers were obtained in electrolyte solutions containing nickel sulphamate with high concentration of W and nonstoichiometric titanium oxides particles (TiOx). The co-deposition of NiW layers with TiOx particles was carried out under potentiostatic conditions on pristine and oxidized carbon fibers by stirring. Comparatively, NiW layers were obtained under the same experimental conditions. The morphology of the deposits was examined by means of scanning electron microscopy (SEM). Secondary crystallization of NiW layers on the surface of the embedded Ti oxides particles was observed. The structure and the chemical states of the elements in the deposits were illustrated by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) respectively. Electrochemical impedance spectroscopy (EIS) was used to study the electrocatalytic activity of these materials for the hydrogen evolution reaction (HER) in acid solution. The results showed that NiW + TiOx layers on oxidized carbon fiber electrodes possess the highest electrocatalytic activity for HER compared with NiW + TiOx layers on nonoxidized carbon fiber electrodes and NiW layers on oxidized carbon fiber electrodes.