VATIS UPDATE Article

Scientists from the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory (BNL), California State University (CSU), the United States, Soochow University, China, Peking University, China, and Shanghai Institute of Applied Physics (SINAP), China, have developed catalysts that can undergo 50,000 voltage cycles with a negligible decay in their catalytic activity and no apparent changes in their structure or elemental composition. The catalysts are “nanoplates” that contain an atomically ordered Pt and lead (Pb) core surrounded by a thick uniform shell of four Pt layers.

To date, the most successful catalysts for boosting the activity of the oxygen reduction reaction (ORR) – a very slow reaction that signi­ficantly limits fuel cell efficiency – have been of the Pt-based core-shell structure. However, these catalysts typically have a thin and incomplete shell (owing to their difficult synthesis), which over time allows the acid from the fuel cell environment to leach into the core and react with the other metals inside, resulting in poor long-term stability and a short catalyst lifetime.

“The goal is to make the ORR as fast as possible with catalysts that have the least amount of platinum and the most stable operation over time. Our PtPb/Pt catalysts show high ORR activity and stability – two parameters that are key to enabling a hydrogen economy – placing them among the most efficient and stable bimetallic catalysts reported for ORR,” said Dong Su, at BNL, who led the electron microscopy work to characterize the nanoplates.