Fig. 5

(a) LSV curves, (b) Overpotential required for j = 10 and 100 mA cm⁻², (c) Tafel slope plots, (d) electrochemical impedance diagram, (e) C_dl to characterize the electrochemically active area for the four catalysts, (f) Electrochemical stability test for 5000 cycles of CV and i−t stability test for up to 15 h at a current density of 13 mA cm⁻².