Degradation analyses of Ru85Se15 catalyst layer in proton exchange membrane fuel cells

Abstract Accelerated degradation tests (ADTs) for the H 2 /air single cell are carried out at 65 °C and ambient pressure by cycling the cell between 0 and 200 mA cm −2 up to 6000 cycles. Membrane electrode assemblies (MEAs) are prepared using the Nafion 212 membrane and the carbon supported platinum as an anode catalyst, as well as the carbon supported Ru 85 Se 15 as a cathode catalyst prepared with five selected Nafion contents and Ru loads to represent the optimized (33% Nafion and 0.27 mg Ru cm −2 ), overloaded (43% Nafion and 0.61 mg Ru cm −2 ) and underloaded (20% Nafion and 0.14 mg Ru cm −2 ) conditions. The lowest cell performance loss of 44% in terms of peak power density is achieved with 33% Nafion and 0.27 mg Ru cm −2 . Very severe losses of 80% and 82% are found for 20% and 43% Nafion contents, respectively, while relatively moderate losses of 57% and 64% for 0.14 and 0.61 mg Ru cm −2 , respectively. Dissolution and migration of Se/Ru and corrosion of carbon support from the catalyst, together with the shrinkage and release of sulfonic acid from the membrane are identified and correlated to decayed cell performances.