Controlling Proton and Electron Transfer Rates to Enhance the Activity of an Oxygen Reduction Electrocatalyst.

An electrochemical approach is developed that allows for the control of both proton and electron transfer rates in the O reduction reaction (ORR). A dinuclear Cu ORR catalyst was prepared that can be covalently attached to thiol-based self-assembled monolayers (SAMs) on Au electrodes using azide-alkyne click chemistry. Using this architecture, the electron transfer rate to the catalyst is modulated by changing the length of the SAM, and the proton transfer rate to the catalyst is controlled with an appended lipid membrane modified with proton carriers.