Oxygen Evolution Co-Catalysts at Fuel Cell Cathodes for Degradation Mitigation during Simulated Start-up Shut-down Cycles

摘要

Start up and Shut down procedures in hydrogen fuel cell automobile industry have become an important component in deciding the long term durability and activity of fuel cell stacks. We herein report a methodology which uses an oxygen evolution reaction (OER) co-catalyst, such as Ru and RuO_2 together with a highly active ORR catalyst. The co-catalyst is applied in the cathode layer with loadings of 0.035 - 0.04 mg_(Ru)/cm~2 and is uniformly mixed with the ORR catalyst prior to electrode preparation. Oxygen evolution catalysts (OER) like Ru/C and RuO_2/C mixed with ORR catalysts enhance the oxidation of water/OH~- to oxygen and therefore provide significant protection of other redox active species at high cathode potentials Our measurements indicate that loss in ECSA, carbon support and activity for ORR catalyst combined with OER was significantly reduced as compared to an unprotected catalyst layer.