Aziridine-Functionalized Multiwalled Carbon Nanotubes: Robust and Versatile Catalysts for the Oxygen Reduction Reaction and Knoevenagel Condensation

This paper describes the exohedral N-decoration of multiwalled carbon nanotubes (MWCNTs) with NH-aziridine groups via [2 + 1] cycloaddition of a tert-butyl-oxycarbonyl nitrene followed by controlled thermal decomposition of the cyclization product. The chemical grafting with N-containing groups deeply modifies the properties of the starting MWCNTs, generating new surface microenvironments with specific base (Bronsted) and electronic properties. Both of these features translate into a highly versatile single-phase heterogeneous catalyst (MW@N-Az) with remarkable chemical and electrochemical performance. Its surface base character promotes the Knoevenagel Condensation with activity superior to that of related state of the art N-doped and N-decorated carbon nanomaterials; the N-induced electronic surface redistribution drives the generation of high-energy surface C sites suitable for O-2, activation and its subsequent electrochemical reduction (ORR).