Nano-architectured Pt-Mo Anode Electrocatalyst for High CO-tolerance in PEM Fuel Cells

PEM fuel cell MEAs with Nafion electrolytes and common cathodes were tested with Pt0.8Mo0.2 alloy and MoOx@Pt core-shell anode electrocatalysts for anode CO tolerance and short-term stability to corroborate earlier thin-film RDE results. Polarization curves at 70 {degree sign}C for the Pt0.8Mo0.2 alloy in H2 with 25 to 1000 ppm CO showed a significant increase in CO tolerance in comparison to PtRu electrocatalysts. MoOx@Pt core-shell electrocatalysts, which showed extremely high activity for H2 in 1000 ppm CO during RDE studies, performed poorly in MEA testing, in comparison to the PtMo and PtRu alloys on a current per total catalyst loading basis. The discrepancy is attributed to residual stabilizer from the core-shell synthesis impacting catalyst-ionomer interfaces. Nonetheless, the MoOx@Pt electrochemical performance, with its reduced Pt content, is comparable or superior to the highly active Pt0.8Mo0.2 electrocatalyst for CO concentrations of 250 ppm or lower on a per gram of precious metal basis.