KINETICS OF HYDROGEN EVOLUTION ON NI-AL ALLOY ELECTRODES

The kinetics of the hydrogen evolution reaction have been studied on Ni-Al alloy electrodes. The electrodes, after leaching aluminium in alkaline solution, are verv active despite their large Tafel slopes. The SEM studies show a formation of deep pores on the electrode surface. The kinetics were studied using an ac impedance technique. It was found that the impedance plots may be explained assuming a fractal model. The logarithm of the charge transfer resistance is a linear function of the overpotential. Using a nonlinear least square approximation it was found that the reaction proceeds through the Volmer-Heyrovsky mechanism and the kinetic parameters were estimated.