Abstract: A novel five-coordinated copper(Ⅱ) complex (Cu［L(ImH)］(ClO4)2), which was self-assembled with imidazole, Cu2+ center, and 2-［bis(2-aminoethyl)amino］ethanol (L), was synthesized. The ligand L bearing an O atom at the hydroxyethyl arm with proper flexibility provided enough variability to adapt the different configuration requirement of Cu2+/Cu+ in the redox process. The pyrolytic graphite (PG) electrode modified with the Cu［L(ImH)］(ClO4)2 complex was constructed. The electrochemical behavior and electrocatalytic activity of the Cu［L(ImH)］/PG electrode for oxygen reduction were studied by cyclic voltammetry and chronoamperometry. The Cu［L(ImH)］/PG electrode exhibited high electrocatalytic activity and stability for oxygen reduction. The reduction current increased with the increase in scan rate, and the plot of Ip to v1/2 was linear. According to the results of potential step chronoamperometry, the electrocatalytic mechanism of oxygen reduction at the modified electrode might be similar to the ECE (E: electrode reaction, C: chemical reaction) process, the number of electron transfer in the reduction process was about 4, and the oxygen was finally reduced to H2O at the modified electrode.

Key words: copper, complex, modified electrode, electrocatalysis, oxygen reduction, mechanism