Demonstration of the importance of oxygenated species at the ends of carbon nanotubes for their favourable electrochemical propertiesElectronic supplementary information (ESI) available: TEM images of cut SWNTs, AFM images of aligned carbon nanotubes, infrared spectra, and experimental procedures. See http://www.rsc.org/suppdata/cc/b4/b415051a/

Definitive evidence is presented for the favourable electrochemical properties of carbon nanotube modified electrodes arising from the ends of SWNTs due to oxygenated carbon species in general, and carboxylic acid moieties in particular, produced during acid purification.