Formic acid (FA), as a promising hydrogen storage carrier, plays a key role in the implementation of a hydrogen economy with its efficient hydrogen evolution, especially for additive-free systems. To this end, we construct a series of tetrahydroquinoxaline-dioximino iridium complexes (Ir/Ln) that meet the above criteria. After optimization of the ligand structure, Ir/L8 (L8 = 6,7-dimethyl-2,3-dioxo-1,2,3,4-tetrahydroquinoxaline) exhibits an initial TOF of 80,000 h⁻¹ at 60 °C (337,500 h⁻¹ at 80 °C), outperforming the previous reported counterparts for additive-free systems. Besides, a possible dehydrogenation mechanism, i.e. the synergistic auxiliary effect of β-NH units, water and HCOOH molecules favored Ir/L8-driven FA decomposition, is adequately elucidated by experimental and theoretical studies, filling the gap in the existing mechanism system. In brief, the ingenious design and systematic research lay the foundation for the efficient release of hydrogen from FA, promising the overall implementation of “green hydrogen economy”.

甲酸（FA）作为一种很有前途的储氢载体，以其高效的析氢性能在氢经济的实施中发挥着关键作用，特别是对于无添加剂系统。为此，我们构建了一系列符合上述标准的四氢喹喔啉-二肟基铱配合物（Ir/Ln）。优化配体结构后，Ir/L8 (L8 = 6,7-dimethyl-2,3-dioxo-1,2,3,4-tetrahydroquinoxaline)在 60 °C ( ^337,500 h ^-1在 80 °C 下），优于之前报道的无添加剂系统。此外，通过实验和理论研究充分阐明了可能的脱氢机制，即β-NH单元、水和HCOOH分子的协同辅助作用有利于Ir/L8驱动的FA分解，填补了现有机制体系简介的空白，巧妙的设计和系统的研究为FA的高效释放氢奠定了基础，有望全面实施“绿色氢经济”。