Electrochemical measurements were performed at room temperature in a three-electrode cell configuration using a potentiostat device (AMETEK Solartron Analytical Modulab). Graphite rod and KCl-saturated Ag/AgCl electrode were employed as counter-and reference electrodes, respectively. Measured potentials were converted according to the following equation: analyses were performed at 20 mV s -1 and chronopotentiometry (CP) analysis was performed at 5 mA cm -2 during 20 h.