Fig. 8. (a) Impedance spectroscopy measurements carried out after different numbers of voltammetric cycles in a 1 M KOH electrolyte at 1.7 V vs. RHE. Simulated curves are presented with solid lines, (b) equivalent circuit model used to fit experimental electrochemical impedance spectra and (c) chronopotentiometric curve recorded for the PSZNi2.5_5 catalyst immobilized onto a Ni foam in nitrogen saturated 1 M KOH electrolyte at a current density of 10 mA cm⁻².