Formation of a Complex Active Center by Ba₂RuH₆ for Nondissociative Dinitrogen Activation and Ammonia Formation

Mild-condition ammonia synthesis from N2 and H2 is a long-thought-after scientific goal practical need, especially for the intensively pursued “green ammonia” production using renewable H2. Barium-containing materials have recently attracted significant attention as promising catalysts, catalyst supports, or mediators effective under mild conditions. Here, we report that ternary barium–ruthenium complex hydride, Ba2RuH6, displays outstanding catalytic activity, which nearly an order of magnitude higher than active BaO-promoted Ru metal (BaO-Ru/MgO) at temperatures below 573 K. Different catalyst, kinetic parameters Ba2RuH6 exhibit interesting temperature dependence. The center, function mechanism, behaviors are investigated with combined experimental computational approach. We find reduction reaction (NRR) preferentially carried out on defected (110) surface Ba H vacancies, in center consisting three atoms one atom plus coordinating hydridic hydrogens catalyze nondissociative hydrogenolysis through dynamic synergistic engagement all components mediating electron proton transfers. Specifically, barium plays unique vital role whole process by directly donating electrons bonding reacting NxHy species. Based proposed pathway, performances analyzed energetic span model, calculated turnover frequencies comparable to results conditions applied this study.