Nitrogen fixation is a complex process involving the transfer of six electrons and protons. Diverging from the conventional Haber-Bosch process, which relies on hydrogen (H₂) to provide both electrons and protons to reduce nitrogen (N₂), homogeneous transition metal complex-catalyzed N₂ reduction reactions (NRR) employ an array of electron and proton donors or even electron donors combined with silanes. As the synthesis of diverse catalytic progress, the categories of donors have seen rapid expansion. However, existing literature only provides summaries regarding the metal, ligands, and mechanism. Despite the significance of electron and proton donor combinations in nitrogen reduction reactions, no literature has thoroughly reviewed this aspect. Therefore, we hereby compiled a comprehensive list of commonly used reagents in N₂ reduction and classified them according to their specific donor combinations. This review presents clear and organized information about these combinations, along with a summary of their general performance trend in NRR with related catalysts. Finally, we conclude the discussion by highlighting key points for researchers to consider when selecting catalysts and donor combinations, with the ultimate goal of advancing the field of nitrogen fixation.

固氮是一个复杂的过程，涉及六个电子和质子的转移。与传统的 Haber-Bosch 过程不同，传统的 Haber-Bosch 过程依靠氢 (H ₂ ) 提供电子和质子来还原氮 (N ₂ )，均相过渡金属络合物催化 N ₂ 还原反应 (NRR) 采用一系列电子和质子供体，甚至电子供体与硅烷组合。随着多种催化合成的进展，供体的类别迅速扩大。然而，现有文献仅提供了有关金属、配体和机理的总结。尽管电子和质子供体组合在氮还原反应中具有重要意义，但没有文献彻底综述这方面。因此，我们在此编制了一份N ₂ 常用试剂的综合列表，并根据其特定的供体组合对其进行了分类。本综述提供了有关这些组合的清晰且有条理的信息，并总结了它们与相关催化剂在 NRR 中的总体性能趋势。最后，我们通过强调研究人员在选择催化剂和供体组合时需要考虑的关键点来结束讨论，最终目标是推进固氮领域的发展。