Support‐Driven Hydrogen Migration Enhances Ammonia Decomposition in Direct Ammonia Protonic Ceramic Fuel Cells

Ammonia, with its high hydrogen density and carbon‐free nature, serves as ideal fuel for direct ammonia protonic ceramic fuel cells (DA‐PCFCs). However, conventional Ni‐based anodes suffer from slow NH 3 decomposition processes and Ni particle sintering, resulting in reduced activity and low stability in DA‐PCFCs. Here, an FeNi catalyst supported on proton‐conducting BaZr 0.8 Y 0.2 O 3‐δ (FN/BZY) is designed, revealing a distinct NH 3 decomposition pathway on the protonic support. The notable metal–support interaction in FN/BZY accelerates N–H bond cleavage and H* species migration, thereby suppressing intermediate accumulation and sustaining continuous hydrogen evolution. Consequently, FN/BZY achieves 85% NH 3 conversion at 525 °C under a gas hourly space velocity of 48 000 mL g cat −1 h −1 . When integrated into a DA‐PCFC, the cell exhibits a peak power density of 963 mW cm −2 at 650 °C and remains stable for 350 h at 600 °C. This work reveals that basic proton‐conductive supports fundamentally increase NH 3 decomposition, thus offering a rational strategy for designing durable and high‐performance anode catalytic layers in DA‐PCFCs.