Cooperative Electrocatalytic O_2 Reduction Involving Co(salophen) with p-Hydroquinone as an Electron-Proton Transfer Mediator

摘要

The molecular cobalt complex, Co(salophen), and para- hydroquinone (H_(2)Q) serve as effective cocatalysts for the electrochemical reduction of O_(2) to water. Mechanistic studies reveal redox cooperativity between Co(salophen) and H_(2)Q. H_(2)Q serves as an electron–proton transfer mediator (EPTM) that enables electrochemical O_(2) reduction at higher potentials and with faster rates than is observed with Co(salophen) alone. Replacement of H_(2)Q with the higher-potential EPTM, 2-chloro-H_(2)Q, allows for faster O_(2) reduction rates at higher applied potential. These results demonstrate a unique strategy to achieve improved performance with molecular electrocatalyst systems.