Preparation and fabrication of NiCo coated TiO2-NTs for hydrogen evolution

Hydrogen production via water splitting is a very attractive way using effective electrocatalysts. One of the effective electrocatalysts that are used in water splitting is NiCo alloys. In this study, highly ordered titanium dioxide nanotubes (TiO2-NTs) are firstly prepared by electrochemical anodization method in terms of being a substrate material for NiCo coatings. Hydrogen evolution behaviors of three types of NiCo coated TiO2-NTs are investigated in 1 M KOH solution at room temperature. Coated surfaces are characterized by scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectroscopy, X-ray diffraction (XRD), and cyclic voltammetry (CV). HER activities of NiCo coated TiO2-NTs are investigated by cathodic current-potential curves, electrochemical impedance spectroscopy (EIS), and electrolysis process. The stability of NiCo-coated TiO2-NTs is also investigated. Results show that TiO2-NTs surface leads to large surface area and high porosity for NiCo nano-particles and thus, HER performance of coatings increases. NiCo-coated TiO2-NTs improves the catalytic HER activity in terms of current density, hydrogen volume, polarization resistance (R-p), and conductivity. Enhanced HER activity can be based on the boosted surface area, conductivity, and more active sites for hydrogen ion adsorption as well as synergistic effects.