Glassy carbon electrodes modified with supramolecular assemblies generated by π-stacking of Cobalt (II) octaethylporphyrins. A 4 electrons-dioxygen reduction reaction occurring at positive potentials

摘要: Abstract A new method of modifying previously oxidized glassy carbon electrode (GCE) using commercial cobalt (II) porphyrin is proposed. This novel assembly presents a significant improvement in terms electroactivity towards the oxygen reduction reaction (ORR), as compared to other reported systems. The device reduces molecular at positive potentials involving 4 electrons, corroborated by kinetic studies. In addition, 46 mV per decade Tafel slope was obtained, evidencing that ORR mechanism would involve chemical step following first electron transfer, or, rate determining be transfer second electron. Concomitant this, studies with different metalloporphirins were accomplished order compare central metal ion effect. Morphological conducted Atomic Force Microscopy (AFM) consistent proposed modification based on structural changes found GCE surface, well obtained differences roughness parameters (R q values). Finally, it demonstrated this system better, electroactivity, than arrays.