Suppressing Metal Dissolution in Multi-Grained Catalysts Through Intragrain Atomic Ordering for Stable Fuel Cells.

Rational design of catalytic nanomaterials is essential for developing high-performance fuel cell catalysts. However, structural degradation and elemental dissolution during operation pose significant challenges to achieving long-term stability. Herein, the development of multi-grained NiPt nanocatalysts featuring an atomically ordered NiPt phase within intragrain is reported. Ultrasound-assisted synthesis facilitates atomic transposition by supplying sufficient diffusion energy along grain boundaries, enabling unprecedented phase formation. The NiPt embedded nanocatalysts exhibit outstanding proton exchange membrane fuel cell performance under both light-duty and heavy-duty vehicle conditions, with significantly reduced Ni dissolution. Under light-duty vehicle conditions, the catalyst achieves a mass activity of 0.94 A mg and a 421 mA cm current density (@ 0.8 V in air), retaining 78% of its initial mass activity after long-term operation. Under heavy-duty vehicle conditions, the multi-grained nanocrystal demonstrates only an 8% decrease in Pt utilization, a 5% power loss, and a 13 mV voltage drop, surpassing U.S. Department of Energy (DOE) durability targets. This study underscores the critical role of the atomically ordered NiPt phase in stabilizing multi-grained NiPt nanocrystals, enhancing both durability and catalytic activity. These findings establish NiPt embedded nanocatalysts as promising candidate for next-generation PEMFC applications, addressing key challenges in long-term operation.