Atomic-Level Insights Into the Durability of Ordered PtNi Intermetallic Electrocatalysts for the Oxygen Reduction...

In Proton Exchange Membrane Fuel Cells (PEMFCs), extensive research has been required to enhance the electrocatalytic efficiency of the oxygen reduction reaction (ORR) while reducing Pt usage by alloying it with other transition metals. Although alloying improves ORR activity through lattice and electronic effects, the second metal often dissolves under acidic operating conditions, leading to the degradation of PEMFC performance. This has motivated the development of core-shell structures, but core metal dissolution can still occur due to segregation under high oxygen coverage. Intermetallic structures have been recently proposed as a promising alternative to address this issue. In this work, a thermodynamically stable, intermetallic-ordered PtNi catalyst supported on carbon was designed to improve durability in acidic environments. Alloyed and ordered PtNi/C samples were electrochemically conditioned to ensure reliable evaluation. A density functional theory (DFT)-based, atomically controlled design approach was employed to elucidate the mechanism of stability enhancement, using dissolution potential as a key descriptor for guiding the design of core-shell structures. These results provide constructive perspective into the durability advantages of intermetallic core-shell catalysts.