Effect of oxidation-reduction surface treatment on the electrochemical behavior of PAN-based carbon fibers

The relationship between surface functionality and electrochemical properties of polyacrylonitrile (PAN)-based carbon fibers (CFs) differentiated by the modification treatment was studied. Oxidative and non-oxidative treatments (i.e. oxidation with ammonium peroxydisulfate (1 M (NH4)(2)S2O8), and heating in hydrogen and argon atmosphere) were used for the modification. The chemical character of the CF surface was estimated by using the titration method and X-ray photoelectron spectroscopy (XPS) analysis. The electrochemical behavior of CFs was studied by the cyclic voltammetry method in oxygen- and helium-saturated solutions. Analysis of concentration and types of C-O bonds in surface acidic functional groups, together with the electrochemical response of CF have shown a close correlation between treatment condition and electrochemical activity of CF in electrolyte solutions. The variation in concentration and type of surface oxygen-containing groups that are able to accelerate or inhibit the electrochemical reactions involving molecular oxygen is discussed. (C) 1999 Elsevier Science S.A. All rights reserved.