The electrochemical characterizations involved in our study were carried with a three-electrode system on VSP (BioLogic Science Instruments, Inc.) with a graphitic rod and a calibrated Hg/HgO (Figure ) as a counter and reference electrode, respectively. The nickel foam (NF) was engaged as a working electrode. Through a drop-casting method on NF, 1 mg cm -2 loading amount of the catalysts was achieved for all working electrodes. To ensure that experiments are conducted under equilibrium conditions of H2O/O2, the electrolyte (1M KOH) was continuously kept in flowing oxygen environments for at least 20 minutes. The linear sweep voltammograms test was performed at a scan rate of 2 mV s -1 with 95% iR compensation. Chronopotentiometry at fix current density of 10 mA cm -2 is used to evaluate the long term stability of the catalyst. The measured voltage values were converted to the reversible hydrogen electrode (R.H.E.) using the following equation:𝐸𝐸 𝑅𝑅𝑅𝑅𝑅𝑅 = 𝐸𝐸 Hg/HgO + 𝐸𝐸 Hg/HgO 0 + 0.059*pH. Tafel slopes were obtained from η = b log j + C; (where η, b, j, and C represent overpotential, Tafel slope, current density, and intercept, respectively). Finally, the overpotential value was obtained by η = E vs (R.H.E) -1.23.