Insights Into Atomic Ordering and Morphological Control Integration Design for Next‐Generation Proton Exchange Membrane Fuel Cells

Proton exchange membrane fuel cells (PEMFCs) are emerging as key energy conversion systems for heavy-duty vehicles, stationary power plants, and high-load infrastructures such as data centers. However, their long-term durability remains critically constrained by transition metal dissolution and structural degradation in alloy catalysts, particularly under heavy-duty target operation (90°C-120°C). Recent studies reveal that the fundamental origin of degradation lies not simply in alloy composition but in the instability of atomic ordering within each grain. Long-range ordered (LRO) intermetallic phase enhances thermodynamic stability through strong atomic bonding, yet their high-temperature synthesis often induces particle coarsening and structural defects. Conversely, short-range ordered (SRO) phase arranges at lower energies, enabling morphology preservation while providing locally stabilized chemical environments that suppress dissolution. Advances in operando microscopy and three-dimensional atomic electron tomography have clarified how atomic-scale ordering, strain distribution, and site occupancy govern degradation pathways. Building on these insights, low-temperature atomic rearrangement strategies coupled with morphology engineering offer a unified framework for achieving stable electronic structures, minimized defect density, and enhanced durability. This review consolidates the mechanistic understanding of ordering-dependent degradation and proposes atomic ordering-morphology integration design for next-generation PEMFC catalysts capable of sustaining high performance under demanding conditions.