Electro analytical thin film electrodes based on a Nafion (TM) - multi-walled carbon nanotube composite

Abstract

A composite film of multi-walled carbon nanotubes (MWNTs) with Nafion(TM) cation exchanger membrane is prepared by cast deposition on glassy carbon electrodes. The morphologies of the MWNT and MWNT/Nafion(TM) modified electrode are characterised by atomic force microscopy (AFM). The MWNTs are cylindrically shaped and uniform with a diameter in the range of 40-60 nm. The MWNT/Nafion(TM) composite film is cast homogeneously onto glassy carbon electrodes. Well-defined voltammetric responses are observed for the Fe(CN)(6)(4-)/Fe(CN)(6)(3-) redox system in aqueous 0.1 M KCl. In contrast to electrodes coated only with Nafion(TM), both anodic and cathodic peak currents depended linearly on the square root of the scan rate over the range of 0.05-0.6 V s(-1), which suggests diffusion-control and fast electron conduction within the membrane. The anodic stripping response for Cd metal from a solution of 1-4 muM in aqueous 0.1 M acetate buffer solution is demonstrated. The results indicate that the composite electroanalytical film composed of MWNT and Nafion(TM) is highly sensitive and suitable for potential electrochemical sensor applications. (C) 2004 Elsevier B.V. All rights reserved.