Properties of Cathode Non-Platinum Catalysts for Oxyhydrogen Fuel Cell with Proton- and Anion-conducting Electrolytes

Abstract

Pyrolysis of nitrogen-containing complexes of iron and cobalt on the surface of disperse carbon materials was used for synthesis of cathode catalysts for oxyhydrogen fuel cells (FC) with proton-conducting (acidic) and anion-conducting (alkaline) electrolytes. The catalysts were characterized by XPS and tested using a thin-film disc electrode and in oxyhydrogen FC under model conditions. Properties of the CoFe/C system prepared by pyrolysis of macroheterocyclic compounds of iron and cobalt on carbon materials (soot HS-72 and multilayer nanotubes (CNT)) were described for the first time. From XPS data, the surface of the catalytic CoFe/C systems is rich in carbon (95,5 at.%), contains nitrogen (2 at.%), oxygen (2 at.%) and metals (0,5 at.%). The data obtained by electrochemical measurements under model conditions revealed that the catalytic systems CoFe/CNT are close to the commercial platinum catalyst 60%Pt/C (HiSPEC9100) in their activity to oxygen reduction in an alkali medium (0,5 M KOH). Half-wave potentials are 0,85 and 0,88 V for catalysts CoFe/CNT and 60%Pt/C (HiSPEC9100), respectively. The maximal specific capacity of the oxyhydrogen FC with an anion-conducting electrolyte is 210 mW/cm2 (a 60%Pt/C (HiSPEC9100) based cathode) and 180 mW/cm2 (CoFe/CNT based cathode). In its characteristics, MEA with the non-platinum cathode compete well with the best analogues described in literature. The results obtained demonstrated the necessity of the further studies on scaling-up the technology for synthesis of the developed non-platinum cathode catalysts and on optimization of the MEA FC architecture based thereon.