Demystifying the Role of Covalently Attached Electron-Proton Transfer Mediator in Oxygen Reduction Reaction Catalyst

The role of covalent attachment of benzoquinone/hydroquinone as electron-proton transfer mediators in ORR is investigated, and it is found that the catalysis is much more efficient as compared to Co(Sal) (Sal = salophen) alone or Co(Sal) and quinone used separately in terms of selectivity toward H<inf>2</inf>O formation. While Co(Sal) has only a 3% Faradaic yield for H<inf>2</inf>O formation, under the same conditions, the Faradaic yield for H<inf>2</inf>O formation is 80% with Co(Sal-H<inf>2</inf>Q).