Highly active and extremely stable L10-PtCoMn ternary intermetallic nanocatalyst for oxygen reduction reaction

Herein, we report a manganese-stabilized ternary intermetallic compound L1(0)-PtCoMn as a highly active and extremely stable nanocatalyst for oxygen reduction reaction (ORR). In the half-cell test, the mass activity (MA) and specific activity (SA) of the optimal component L1(0)-PtCo0.8Mn0.2 are approximately 8.5 and 8.1 times higher than Pt/C, respectively, showing outstanding ORR catalytic activity. In PEMFC tests, the L1(0)-PtCo0.8Mn0.2 cathode exhibits an excellent MA (0.954 A/mg(Pt) at 0.9 ViR-free) and a superior durability (only similar to 8.6% loss in MA and similar to 5 mV voltage drop at 0.8 A cm(-2) after 30k ADT cycles), surpassing most of reported Pt-based ORR catalysts. Theoretical calculations reveal that incorporating Mn not only optimizes the adsorption energy (Delta E-O*) of the intermediate O* and thus enhance ORR activity, but also facilitates the formation of the order-structured L1(0)-PtCoMn alloy and strengthens the interatomic interaction forces, leading to its superb durability. This work provides new highlights for developing highly ORR performing nanocatalysts for PEMFCs.