Hydrogen evolution reaction at Pd-modified carbon fibre and nickel-coated carbon fibre materials

• Electrodeposition of Pd enhances kinetics of HER at CF and NiCCF materials.
• Pd modifies electrochemically active surface of CF and NiCCF materials.
• Pd-modified CF and NiCCF seem suitable as cathodes in water electrolysers.

The present paper reports on A.C. impedance study of hydrogen evolution reaction (HER), carried-out on Pd-modified carbon fibre (CF) and nickel-coated carbon fibre (NiCCF) materials. The HER was examined in 0.5 M H2SO4 solution for electrochemically deposited Pd on Hexcel 12K AS4C CF and Toho-Tenax 12K50 NiCCF tow materials. Kinetics of the hydrogen evolution reaction was studied at room temperature, over the cathodic overpotential range: −100 to −1200 mV vs. RHE. Corresponding values of charge-transfer resistance, exchange current–density for the HER and other electrochemical parameters for the examined catalyst materials were derived. Thus, Pd modification of CF and NiCCF materials (at ca. 1.5 wt.% Pd) dramatically increased the exchange current–density parameter by about 5300× and 445× for carbon fibre and nickel-coated carbon fibre tows, correspondingly.