Stabilizing transition metals (M) in MPt alloy under acidic conditions is challenging, yet crucial to boost Pt catalysis toward oxygen reduction reaction (ORR). We synthesized ~9 nm hard-magnet core/shell L1 0-CoPt/Pt nanoparticles with 2–3 atomic layers of strained Pt shell for ORR. At 60°C in acid, the hard-magnet L1 0-CoPt better stabilizes Co (5% loss after 24 hr) than soft-magnet A1-CoPt (34% loss in 7 hr). L1 0-CoPt/Pt achieves mass activities (MA) of 0.56 A/mg Pt initially and 0.45 A/mg Pt after 30,000 voltage cycles in the membrane electrode assembly at 80°C, exceeding the DOE 2020 targets on Pt activitymore »
Fe Stabilization by Intermetallic L1 0-FePt and Pt Catalysis Enhancement in L1 0-FePt/Pt Nanoparticles for Efficient Oxygen Reduction Reaction in Fuel CellsWe report in this article a detailed study on how to stabilize a first-row transition metal (M) in an intermetallic L1 0-MPt alloy nanoparticle (NP) structure and how to surround the L1 0-MPt with an atomic layer of Pt to enhance the electrocatalysis of Pt for oxygen reduction reaction (ORR) in fuel cell operation conditions. Using 8 nm FePt NPs as an example, we demonstrate that Fe can be stabilized more efficiently in a core/shell structured L1 0-FePt/Pt with a 5 Å Pt shell. The presence of Fe in the alloy core induces the desired compression of the thin Ptmore »
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