Electrochemical reduction of oxygen on small platinum particles supported on carbon in concentrated phosphoric acid—II. Effects of teflon content in the catalyst layer and baking temperature of the electrode

Abstract

A relation between hydrophobicity (or wettability) of a porous gas diffusion electrode for use in a phosphoric acid fuel cell and its cathode performance (activity toward electrochemical oxygen reduction) was examined. The hydrophobicity of the gas diffusion electrode was regulated by changing either the amount of Teflon (PTFE) content in the catalyst layer or baking temperature of the electrode. The Tafel slope for electrochemical oxygen reduction became twice as high as that of the ordinary electrode when the wettability of electrode toward phosphoric acid was high. This fact supports a flooded agglomerate model as the operation mode of this type of porous gas diffusion electrode.