Characterisation of membranes for electrochemically aided gas separation: Morphology of platinum deposition

A novel membrane technique to effect electroinduced facilitated transport of ethylene in Pt-containing ion exchange membranes was recently demonstrated. It was shown that by applying an electric current to such a membrane, the permeability of ethylene increased six-fold compared with that of an initial Pt-coated membrane without applied current. Experiments have been carried out with platinum-coated Nafion membranes in Cu2+ ionic form to determine the permeability of ethylene. This paper deals with the characterisation of these membranes by various techniques, such as scanning electron microscopy (SEM), Rutherford backscattering (RBS) and particle-induced X-ray emission (PIXE) techniques. A relevant literature survey is also presented. An idealised theoretical model describing concentration profiles of copper ions in various valence states in the membrane is formulated. (C) 1998 Elsevier Science B.V. All rights reserved.