Impacts of Cathode Loading on Ru Crossover Related PEFC Durability

Abstract

The use of platinum-ruthenium anode catalyst to improve tolerance of fuel cells to carbon monoxide present in reformed fuels can result in additional durability concerns, due to instability of the Ru. The degradation of Ru from PtRu/C catalyst is not only a problem for the anode but also for the cathode, as degraded Ru dissolves and crosses over to the cathode, resulting in degraded performance over the fuel cell lifetime. In the current study we investigated how the Ru crossover related performance issues is exacerbated if the cathode Pt loading is varied from 0.4 mg/cm 2 to 0.1mg/cm 2 Pt for a constant anode PtRu/C loading of 0.1 mg/cm 2 through Ballard's anode stress test protocols mimicking the anode degradation due to air-air start-up/shut-down (SU/SD). Unacceptable performance losses have been observed with lower Pt loadings in H 2 /air polarizations. The Ru crossover was systematically characterized and quantified using both electrochemical and physiochemical techniques.