Interfacial Synergy in Ni _x Mg _1‐x O/CeO ₂ for Efficient Ammonia Decomposition

Abstract Hydrogen production via ammonia decomposition presents a promising way to solve the difficulties of hydrogen storage and transportation. Ni‐based catalysts have demonstrated promising catalytic activity for this reaction, making them a commercially viable choice, yet their activity and stability for industrial applications remain ongoing challenges. Here, we report a robust Ni x Mg 1‐x O/CeO 2 catalyst that overcomes these limitations. The catalyst composes of Ni x Mg 1‐x O solid solution with atomic dispersed Ni and CeO 2 , and demonstrates an impressive 99.1% NH 3 conversion close to the thermodynamic limitation at 525 °C, and exceptional stability during reaction of 5,000 h at 550 °C, outperforming Ni‐based catalysts reported to date. Characterizations and density functional theory calculations reveal a remarkable interfacial synergy effect between the Ni x Mg 1‐x O solid solution and CeO 2 . Ni single atoms in Ni x Mg 1‐x O efficiently activate N‒H bond dissociation of NH 3 , and the resulting H atom readily spills over to CeO 2 , preventing H‐poisoning of the Ni sites. Concurrently, CeO 2 donates electrons to Ni, promoting the recombination of N species to form N 2 , thus boosting the overall performance. This study offers a general strategy for designing high‐performance ammonia decomposition catalysts through the deliberate constructing interfacial active sites.