Well-aligned carbon nanotubes: Synthesis, modification and applications in electrochemistry

Abstract

Vertically aligned multi-walled carbon nanotubes (MWNTs) were successfully synthesized on Fe, Co or Ni-filmed silicon wafers, quartz plates and Ta foils by CVD with ethylenediamine as a precursor. The realization of the growth of MWNTs onto the Ta foil promises the applications of carbon nanotubes as electrodes in the electrochemical systems. MWNTs-on-Ta electrodes were experimentally found to have good conductivity, highly chemical stability, and highly accessible surface area and can be used directly to detect the important and specific biological molecules, such as uric acid (UA), ascorbic acid (L-AA) and glucose. To improve sensitivity and selectivity, the as-grown carbon nanotubes on the Ta foil were further modified by non-covalent immobilization with porphyrins or phthalocyanines, Pt nanoparticles, enzyme, poly(o-aminophenol) (POAP) film or molybdenum oxide film. The modified electrodes exhibit high electrocatalytic activities toward O2, H2O2, glucose, methanol or bromate, and thus possess potential applications in biological and material sciences.