Multistep one-electron photoelectrocatalytic reduction of oxygen at tris(2,2'-bipyridine)ruthenium(II)-incorporated Nafion- and clay-coated electrodes in the presence of macrocyclic cobalt(II) complexes

摘要

The electrocatalytic reduction of oxygen was carried out at Nafion- and clay-modified electrodes in the presence of tetraazamacrocyclic cobalt(III) complexes. Long-time electrolysis experiments were performed, and the faradaic yield of H_2O_2 and the rate of H_2O_2 production were found to be higher at clay-coated electrodes than at Nafion-coated electrodes. In the case of the photoelectrocatalytic reduction of oxygen at Pt/Nafion/[Ru(bpy)_3]~(2+) and Pt/H~+-montmorillonite/[Ru(bpy)_3]~(2+) electrodes, the amounts of H_2O_2 produced increased by a factor of two under light irradiation condition when compared to dark. The faradaic yield of H_2O_2 under irradiation conditions was determined at the modified electrodes, and a mechanism for multistep one-electron photoelectrocatalytic reduction of oxygen was proposed.