Exploring Earth-abundant metal oxides for ambient N₂ (Lewis base) reduction to value-added NH₃, an essential commodity for modern industries, has extreme significance. However, due to their insufficient Lewis acidity and unfavorable electronic parameters, resulting in poor N₂ adsorption, instability of key N intermediates (NNH*/NNH₂*/N*), and preference for hydrogen evolution, the NH₃ selectivity and yield rate with metal oxides are far from satisfactory. Herein, theoretical predictions reveal that tuning the electronic structure of defective Co₃O₄ (Co₃O_4-x) via a single-Ru-atom dopant can cooperatively enhance the N₂ adsorption, driven by strong Ru_4d-N_2p orbital coupling, and stabilize the key N-intermediates, further suppressing the H* dimerization and significantly boosting the NH₃ selectivity. Motivated by DFT predictions, we introduced optimal single-Ru-atom dopants to maximize the Lewis acidity of Co₃O₄ with in situ-generated oxygen defects (Ru_1.4Co₃O_4-x), which exhibited an excellent N₂-fixation activity with a high NH₃ Faradaic efficiency (40.2%) and yield rate (39.4 μg/h/mg_cat; 2.67 mg/h/mg_Ru) at 0 V (vs RHE), along with long-term stability and 2.5 times higher selectivity than pristine Co₃O_4-x, outperforming the state-of-the-art Ru/C.

中文翻译：

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单金属原子掺杂剂增加金属氧化物的路易斯酸度并促进固氮

探索地球上丰富的金属氧化物以将环境中的 N ₂（刘易斯碱）还原为具有附加值的 NH ₃，这是现代工业必不可少的商品，具有极其重要的意义。然而，由于它们的路易斯酸度不足和不利的电子参数，导致 N ₂吸附差，关键 N 中间体 (NNH*/NNH ₂ */N*)不稳定，并且偏爱析氢，NH ₃选择性和产率与金属氧化物相去甚远。在此，理论预测表明，调整缺陷 Co ₃ O ₄ (Co ₃ O _{4- x})通过单Ru原子掺杂剂可以协同增强N ₂吸附，在强Ru _4d -N _2p轨道耦合的驱动下，稳定关键的N-中间体，进一步抑制H*二聚化并显着提高NH ₃选择性。受 DFT 预测的启发，我们引入了最佳的单 Ru 原子掺杂剂，以最大限度地提高 Co ₃ O ₄的路易斯酸度，并具有原位产生的氧缺陷（Ru _1.4 Co ₃ O _{4- x}），表现出出色的 N ₂固定具有高 NH _{3 的}活性法拉第效率 (40.2%) 和产率 (39.4 μg/h/mg _cat ; 2.67 mg/h/mg _Ru ) 在 0 V (vs RHE)，以及长期稳定性和比原始 Co ₃ O高 2.5 倍的选择性_{4- x}，优于最先进的 Ru/C。