Influence of Platinum Deposits on Properties and Degradation of Nafion® Membranes

Kurzfassung

It is well known that platinum (Pt) from the electrodes is dissolved during operation of PEFC and can deposit in the electrolyte membrane. This deposition may alter membrane properties and induce degradation even though many aspects of the complex interactions are controversial. This contribution discusses the approach of artificial deposition of Pt to mimic this effect and compare the result to naturally aged membranes in PEFC. To systematically investigate this influence, we compared pristine membranes with membranes impregnated with different amounts of Pt in a degradation test. Specifically, this paper presents results regarding Pt particle distribution in the membrane, mass transport in the membrane as well as membrane decomposition. Our investigation revealed that particle size, not particle concentration, is the dominating parameter for the extent of membrane decomposition. In context with other studies, our data suggest that Pt concentration induces ionomer decomposition but its distribution is of paramount importance for the extent of membrane degradation.