Fig. 12

(a) Nyquist diagrams of G, GP and GPNiCu electrodes in NaOH 0.1 mol/L (in addition of GPNiCu electrode equivalent circuit) (b) Nyquist diagrams of the GPCuNi electrode in NaOH 0.1 mol/L at −1.49 V Ag/AgCl dc potential after 20, 50 and 100 s of charging.