After measuring background ferricyanide losses for 24 h, the ferricyanide catholyte was spiked with ~2 mM 2,6-DHAQ anolyte. Strikingly, once 2,6-DHAQ was added (dashed line, Figure ), there is a small initial drop in the amount of ferricyanide followed by a three-fold increase in the ferricyanide loss rate to 1.8 x 10 -3 mol dm -3 h -1 . Control experiments were conducted where the catholyte mixture was spiked with the same volume of 1 M KOH (i.e., with no quinone present) and no drop in ferricyanide or increase in loss rate was observed (Figure ). Intriguingly, the ferricyanide loss rate measured during this part of the experiment is lower when performed in H2O