Interfacial Synergy in Ni_xMg_1-xO/CeO₂ for Efficient Ammonia Decomposition

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_xMg_1-xO/CeO₂ catalyst that overcomes these limitations. The catalyst composes of Ni_xMg_1-xO solid solution with atomic dispersed Ni and CeO₂, and demonstrates an impressive 99.1% NH₃ 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_xMg_1-xO solid solution and CeO₂. Ni single atoms in Ni_xMg_1-xO efficiently activate N‒H bond dissociation of NH₃, and the resulting H atom readily spills over to CeO₂, preventing H-poisoning of the Ni sites. Concurrently, CeO₂ donates electrons to Ni, promoting the recombination of N species to form N₂, 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.