Strain‐Engineered Interfacial Locking of Ruthenium Nanocatalysts for Ultra‐Stable Ammonia‐To‐Hydrogen Conversion

Scalable implementation of ammonia as a clean hydrogen carrier critically depends on the development of catalysts that simultaneously deliver high conversion efficiency and long‐term durability under practical operating conditions. Herein, it is demonstrated that the long‐standing activity–stability trade‐off in metal nanocatalysts can be overcome through strain‐engineered interfacial locking, a strategy that exploits lattice mismatch to electronically optimize and crystallographically stabilize active sites. By constructing a lattice‐mismatched Y 2 O 3 /Ru interface, interfacial strain is introduced to thermodynamically favor exposure of the Ru(101) facet while kinetically suppressing sintering. This strain‐locked configuration maintains optimal electronic states for ammonia dehydrogenation and delivers enhanced structural robustness. The resulting catalyst achieves 99.3% NH 3 conversion at 450°C with a space velocity of 30,000 mL·g cat −1 ·h −1 and retains high performance for over 300 h with negligible degradation, demonstrating remarkable durability under high‐temperature conditions. When integrated into a compact stacked microchannel reactor, the system delivers a hydrogen production rate of 3552 L·h −1 , highlighting its high volumetric productivity and potential for decentralized hydrogen production. This work establishes strain‐mediated interfacial facet control as a promising design strategy for durable, high‐performance catalytic materials, addressing a key materials challenge in the emerging hydrogen economy.