High sensitivity to Cu2+ions of electrodes coated with ethylenediamine-modified multi-walled carbon nanotubes

Ethylenediamine-modified multi-walled carbon nanotubes (MWNTs-NH2) were prepared and characterized with a Fourier transform infra-red (FT-IR) spectrometer and a transmission electron microscope (TEM). Meanwhile, the electrochemical behaviour of Cu2+ ions (aq) on the electrodes coated with MWNTs-NH2 was investigated by using cyclic voltammetry. The results show that the electrodes coated with MWNTs-NH2 exhibit high sensitivity to Cu2+ ions (aq) with a detectable concentration of 1 × 10−10 mol dm−3. As compared with the bare indium-doped tin oxide (ITO) electrodes, the sensitivity to Cu2+ ions of the electrode coated with MWNTs-NH2 is enhanced by four orders, implying that the carbon nanotubes modified with functional groups may be used in the fabrication of highly sensitive sensors to detect trace Cu2+ ions (aq).