. Instrumentation
The electrochemical analyses were carried out using a μ-Autolab III potentiostat (Metrohm Autolab B. V., Utrecht, Netherlands). The voltammetric measurements were obtained in a conventional threeelectrode electrochemical cell (internal volume of 16 mL) using glassy carbon electrode (GCE, diameter of 1.6 mm) as working electrode. The auxiliary and reference electrodes were a miniaturized Ag/AgCl (saturated KCl) [22] and platinum wire, respectively