Abstract: The IrO2-Ta2O5 coating electrodes were prepared by thermal decomposition and supported on TiN films synthesized by multi-arc ion plating. The electrocatalytic properties of coating cathodes for hydrogen evolution reaction (HER) were investigated by cyclic polarization combined with scanning electron microscope, energy dispersive X-ray spectroscopy, and X-ray diffraction. The results showed that there existed TiN substrates on the electrodes and the electrode calcined at 420 ℃ exhibited the best electrocatalytic activity for HER. Electrode potential for hydrogen evolution on coating electrodes was -0.26 V (vs SCE). The Tafel slope was -0.04 V in the low overpotential region of HER. The structure of oxide electrodes was changed by a multitude of hydrogen atoms adsorbed on the electrode surface in the high overpotential region of HER, which restrained the cathodic reduction reaction of oxygen. These results suggest primarily that it is feasible using TiN as support for the IrO2-Ta2O5 coating cathode.

Key words: titanium nitride, iridium oxide, tantalum oxide, electrocatalysis, hydrogen evolution reaction