The anthraquinone mediated one-electron reduction of oxygen in acetonitrile

► Oxygen reduction at a boron-doped diamond electrode in acetonitrile. ► The redox potential for the first electron reduction of anthraquinone can be tuned through variation of the substituent groups. ► The mediated one-electron reduction of oxygen occurs rapidly with a measured forward rate constant of 7(±3) × 106 M−1 s−1.