Kinetics of Hydrogen Evolution Reaction at Nickel-Coated Carbon Fiber Materials in 0.5 M H2SO4 and 0.1 M NaOH Solutions

The present paper reports an ac impedance study of the hydrogen evolution reaction (HER) at nickel-coated carbon fiber (NiCCF) materials. The HER was examined in 0.5 M H2SO4 and 0.1 M NaOH solutions for selected NiCCF composites (and comparatively for Ni wires) that were produced by electro (or electroless) deposition of a thin layer (ca. 0.5 mu m) of Ni onto a 12,000-filament carbon fiber tow material. The kinetics of the HER at NiCCFs were studied at room temperature over the cathodic overpotential range of -100 to -500 mV per reversible hydrogen electrode. The corresponding values of the charge-transfer resistance, as well as the exchange current-density parameters for this reaction, were derived for all studied NiCCF composites. Also, a comparison between these parameters, obtained in H2SO4 and NaOH solutions, was made.