Nanoimpacts Reveal the Electron-Transfer Kinetics of the Ferrocene/Ferrocenium Couple Immobilised on Graphene Nanoplatelets

The big reveal: The kinetics of the ferrocene/ferrocenium (Cp2Fe/Cp2Fe+) redox couple in aqueous solution are evaluated by using the nanoimpacts method. Single graphene nanoplatelets (GNPs) modified with poly(vinylferrocene) are allowed to impact a microelectrode. For the duration (ca. 10–100 ms) of the impacts, the GNP adopts the potential of the electrode and acts as a “chemically modified nanoelectrode”. The study of individual impacts facilitates the resolution of fast electron-transfer kinetics that, for the Cp2Fe/Cp2Fe+ couple, is shown to be at least 3±1 s−1.