Influence of PtCu/C Catalysts Composition on Electrochemical Characteristics of Polymer Electrolyte Fuel Cell and Properties of Proton Exchange Membrane

Abstract

The present work aimed to investigate the influence of “weakly bound“ copper dissolution from the surface of bimetallic PtCux/C catalysts on the properties of proton exchange membrane and the membrane electrode assembly (MEA) in general. A number of PtCux/C materials have been obtained by the simultaneous reduction in copper and platinum precursors in the course of liquid-phase synthesis with a varying ratio of metals from PtCu2.0/C to PtCu0.3/C. All bimetallic PtCux/C electrocatalysts after the activation stage exhibit high activity in the oxygen electroreduction reaction. The PtCux/C catalysts in “as prepared” state were tested in MEA. The increase in Cu content in PtCux/C catalysts led to a decrease in current density of MEA while its resistance was almost independent of the Cu fraction in the catalyst. The membrane saturation degree by Cu2+-ions after MEA testing did not exceed 40%, even in the case of the PtCu2.0/C material. The main reason for the degradation of membrane electrode assembly with PtCux/C materials is the transport limitation caused by the contamination of Nafion in three catalytic layer by “weakly bound” copper ions.