Mechanically interlocked carbon nanotubes as a stable electrocatalytic platform for oxygen reduction.

Mechanically interlocking redox-active anthraquinone (AQ) like a rotaxane onto single-walled carbon nanotubes (AQ-MINT) gives a new and advanced example of a non-covalent architecture for an electrochemical platform. Electrochemical studies of AQ-MINT as an electrode reveal enhanced electrochemical stability in both aqueous and organic solvents compared to physisorbed AQ-based electrodes. While maintaining the electrochemical properties of the parent anthraquinone molecules, we observed a stable oxygen reduction reaction (ORR) to hydrogen peroxide (HO). Using such AQ-MINT electrodes, 7 and 2µmol HO were produced over 8h under basic and neutral conditions, while the control system of SWCNT showed 2.2 and 0.5µmol respectively. These results reveal the potential of this rotaxane-type immobilization approach for heterogenized electrocatalysis.