Two-stage confinement derived small-sized highly ordered L1₀-PtCoZn for effective oxygen reduction catalysis in PEM...

Intermetallic ordered PtCo is effective for high oxygen reduction reaction (ORR) activity and stability. However, preparing small-sized, highly ordered PtM alloys is still challenging. Herein, we report a controlled two-stage confinement strategy, in which highly ordered PtCoZn/NC nanoparticles of 5.3 nm size were prepared in a scalable process. The contradiction between the high ordering degree with the small particle size as well as the atomic migration with the space confinement was well resolved. An outstanding PEMFC performance was achieved for L1₀-PtCoZn/NC with a high mass activity (MA) of 1.21 A/mg_Pt at 0.9 V_iR-free, 80.1 % MA retention after 30 k cycles in H₂-O₂ operation, and a high mass-specific power density of 8.24 W mg^-1_Pt in H₂-Air operation with a slight loss of cell voltage@0.8 A cm^-2 of 28 mV after 30 k cycles. The high performance can be ascribed to the high Pt area exposure, the enhanced Pt-Co coupling, and the prevented agglomeration in the mesoporous carbon wall. Overall, this strategy may contribute to the commercialization of fuel cells.