STUDY OF ELECTRODE ACTIVITIES TOWARDS THE HYDROGEN EVOLUTION REACTIONBY AC-IMPEDANCE SPECTROSCOPY

Electrical equivalent models were tested for the description of the hy drogen evolution reaction on various polycrystalline and rough electro des in alkaline solution. It was found that the model containing the c onstant phase element best describes the experimental impedance curves , but in some cases the fractal or porous electrode models had to be u sed. Determination of the surface roughness allowed us to estimate the real electrode activity. It was found that, except for the electrodes containing noble metals, the main contribution to the activity arises from the large surface area.