In-situ exsolved Ru–Fe alloy on Sr2Fe1.4Ru0.1Mo0.5O6-δ for enhanced ammonia decomposition activity and durability in protonic ceramic fuel cells

The practical application of direct-ammonia protonic ceramic fuel cells (DA-PCFCs) is constrained by the sluggish decomposition of ammonia and the structural degradation of conventional Ni-based anodes. Herein, a multifunctional anode is developed by depositing a Sr 2 Fe 1.4 Ru 0.1 Mo 0.5 O 6-δ (SFRM) perovskite catalytic layer onto a Ni-BaZr 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δ cermet. Under operating conditions, this layer enables the in-situ exsolution of uniformly dispersed and sintering-resistant Ru–Fe alloy (RFA) nanoparticles, thereby creating a stable and catalytically active interface. The SFRM-modified single cell achieves peak power densities of 1.33 cm –2 and 1.02 cm –2 at 700 °C in H 2 and NH 3 , respectively, with the NH 3 -fueled performance representing a 15.9 % improvement over the unmodified single cell. Moreover, the cell exhibits excellent durability, operating stably for over 100 h in NH 3 . Combined experimental and density functional theory calculations reveal that the exsolved RFA nanoparticles not only lower the energy barrier for NH 3 dehydrogenation but also, via strong metal-support interaction, regulate interfacial charge transfer and suppress Ni 0 coarsening. This strategy successfully decouples high catalytic activity from long-term stability, providing an effective pathway for durable, high-performance DA-PCFCs.