Nickel-rare earth hydrogen storage alloy (Ni-AB55) composite electrodes were prepared by the electrodeposition technique, and their electrocatalytic characteristics for hydrogen evolution reaction (HER) in 28% KOH solution were investigated by steady-state polarization curves and electrochemical impedance spectroscopy (EIS). The morphology of the electrodes was examined by using scanning electron microscopy (SEM). The experimental results show that in comparison with those of the electrodes electrodeposited with pure Ni, the Ni-AB5 composite electrodes exhibit a lower overpotential and reaction resistance, a higher exchange current density and specific surface area for HER. The standard free activation enthalpy of HER on the pure-Ni and Ni-AB5 electrodes is 74.2 kJ/mol and 39.8 kJ/mol respectively. Thus the Ni-AB5 composite electrodes possess a superior electrocatalytic activity for HER as related to the pure-Ni electrodes. The main pathway for HER on the Ni-AB5 composite electrodes in alkaline solutions is Volmer-Heyrovsky with the electrochemical desorption as the rate-determining step.
|Number of pages||5|
|Journal||Tianjin Daxue Xuebao (Ziran Kexue yu Gongcheng Jishu Ban)/Journal of Tianjin University Science and Technology|
|State||Published - Jun 2005|
- Composite electrode
- Hydrogen evolution reaction
- Rare earth hydrogen storage alloy