Electrochemical oxygen reduction at composite films of Nafion®, polyaniline and Pt

Conducting polymer composite films comprised of polyaniline (PANI) and Nafion are prepared and investigated as a matrix for platinum (Pt) particles deposited both chemically and electrochemically. The resulting electrocatalytic films are assessed with respect to their potential use for the electrochemical reduction of oxygen. The permeability of a PANI-Nafion film to dissolved oxygen is determined to be similar to 50% larger when compared to PANI-camphorsulfonic acid (CSA). A chemical method for dispersing Pt in the composite films is developed which makes use of the reducing power of alcohols present in commercial Nafion solution. Films cast from a solution of PANI and Nafion containing chemically reduced platinum demonstrate a marked improvement in electrocatalytic activity compared to films prepared in the absence of PANI. These composite films are compared with films cast from a suspension of Nafion, PANI and Pt black, with similar results. (C) 1999 Published by Elsevier Science Ltd. All rights reserved.