To exploit the ammonia as a carrier for sustainable energy, development of efficient catalysts is highly desired. Oxide supported Ru catalysts have been widely studied in ammonia synthesis for their superior catalytic performances under mild conditions. Here, sub-nanometer Ru clusters on La₂O₃ (Ru clusters/La₂O₃) catalyst has been synthesized and exhibits superior catalytic performance in ammonia synthesis under mild conditions. Multiple characterizations results reveal that surface La-H species, in situ generated on the surface of catalyst, can significantly boost the activity of Ru clusters/La₂O₃ catalyst in ammonia synthesis. Detailed mechanistic studies demonstrate that the active La-H species on the La₂O₃ can not only promote activation and dissociation of nitrogen molecules but also directly involve in ammonia synthesis reaction process via a La-H species-mediated reaction pathway. This work promotes molecular level understanding the active sites and reaction mechanism under real reaction conditions, and will also offer opportunity for guiding the design of efficient Ru-based catalysts for ammonia synthesis.

为了利用氨作为可持续能源的载体，非常需要开发高效的催化剂。氧化物负载的 Ru 催化剂因其在温和条件下优异的催化性能而在氨合成中得到广泛研究。_{在此，合成了 La 2} O ₃上的亚纳米 Ru 簇（Ru 簇/La ₂ O ₃）催化剂，并在温和条件下在氨合成中表现出优异的催化性能。多重表征结果表明，在催化剂表面原位生成的表面 La-H 物种可以显着提高 Ru 团簇/La ₂ O _3的活性合成氨的催化剂。详细的机理研究表明，La ₂ O ₃上的活性La-H物种不仅可以促进氮分子的活化和解离，而且还通过La-H物种介导的反应途径直接参与氨合成反应过程。这项工作促进了分子水平上对真实反应条件下活性位点和反应机理的理解，也将为指导用于氨合成的高效钌基催化剂的设计提供机会。