Carbon nanotube-epoxy composites for electrochemical sensing

Rigid and conductive carbon nanotube-epoxy composite (CNTEC) electrodes were constructed from two kinds of multiwall carbon nanotubes differing in the length (0.5–2 and 0.5–200 μm) mixed with epoxy resin. The electrochemical behavior of CNTEC electrodes was characterized by using cyclic voltammetry of ferricyanide, NADH and hydrogen peroxide. The behavior of CNTEC electrodes prepared with different percentages of CNT has been compared with that of graphite-epoxy composite (GEC) electrode. It was found that long-carbon nanotube (0.5–200 μm) based epoxy composite electrodes show strong electrocatalytic activity towards NADH and hydrogen peroxide while short-carbon nanotube (0.5–2 μm) based epoxy composites show similar oxidation potential as graphite-epoxy composite electrode for the both NADH and H2O2. In all cases, CNTEC electrodes provide better reversibility, peak shape, sensitivity and stability compared with GEC electrode. The obtained experimental results demonstrate remarkable electrochemical and mechanical advantages of carbon nanotube composites compared to graphite composites for sensor applications.