Platinum-containing polypyrrole coatings on stainless steel electrodes for oxygen reduction in aprotic media

Abstract

The superoxide ion may be electrochemically generated in an aprotic medium [1]. Sawyer et al. investigated the mechanism of decomposition of various chlorinated organic compounds [2], as well as CC14 and DDT using superoxide [3]. This work suggests that the superoxide ion preferentially degrades organic compounds which have a higher chlorine content. The removal of chlorine from organic wastes is a costly process involving incineration [4]. Since there is less of an energy requirement with the electrochemical method, savings in costs of decomposition would be significant. Studies are currently being directed in this area [5]. This work proposes a system of generating superoxide on a large scale in an aprotic medium for the removal of chlorine from chlorinated solvent waste. This was attempted in two configurations; a fluidized bed system similar to that of Fleischmann [6] and Rolison [7] and a dispersion of platinum particles in a polypyrrole matrix. Platinum has previously been deposited in Nation | [8], poly(4-vinylpyridine) [9], and polypyrrole [10]. Oxygen reduction in an aqueous medium has been achieved using this latter system as well as with layers containing catalytic centres such as cobalt porphyrins [11], or metallo-phthalocyanines [12]. This work consists of preliminary experiments involving depositing polypyrrole on stainless steel, incorporating platinum and using this modified electrode to decompose CC14.