Enhancing Effect of an Amino Acid Residue Model for the Electrochemical Water Oxidation Catalyst Confined in a Polymer Membrane

The activity of an electrocatalytic oxygen evolving center (OEC) molecule based on the trinuclear Ru complex, Ru−red ([(NH 3 ) 5 Ru−O−Ru(NH 3 ) 4 −O−Ru(NH 3 ) 5 ] 6+ ) codispersed with an amino acid residue model compound in a Nafion membrane was studied. The activity of the OEC molecule increased remarkably in the presence of p -cresol ( p -Cre), a Tyr model compound. The activity was analyzed based on the intermolecular distance distribution in terms of charge transfer distances between the OEC molecules mediated by p -Cre, their critical decomposition distance, and the intrinsic activity. The charge transfer distance increased remarkably from 1.28 to 2.25 nm by the presence of p -Cre, suggesting that p -Cre works as a mediator for the charge transfer.