Effect of the conditions of electropolymerization on the electrocatalytic response of non-metalled-poly-tetraaminophthalocyanine-modified electrodes toward the reduction of oxygen

The macrocyclic ligand, tetraaminophthalocyanine, was electropolymerized on a glassy carbon electrode by continuously potentiodynamic scans, using two different solvents, dimethylsulfoxide and dimethylformamide. In the first case, an over-oxidation can takes place, which partially destroy the film a nd inhibits its electrocatalytic activity for the reduction of oxygen compa red to the polymer grown in dimethylformamide. To avoid this over-oxidation , two possible ways can be used: to achieve the electropolymerization durin g a lower number of potentiodynamic scans or using a positive potential lim it shifted to more negative potentials. If a narrow potential interval is u sed, the electrocatalytic behavior of the polymer is similar to that obtain ed in dimethylformamide. However, if a wide potential interval is used but only during few potentiodynamic scans, it is possible to obtain a polymer w ith a new redox signal that presents a very interesting electrocatalytic ac tivity for the reduction of molecular oxygen.