Nitrogen Speciation Dictates Industrial-Current Oxygen Reduction in Metal-Free Macrocycles for H2O2 Synthesis.

Oxygen activation is a cornerstone of sustainable electrosynthesis, yet controlling reactive intermediates without metallic centers remains challenging at industrial current densities. Here we establish nitrogen speciation as a molecular descriptor for governing oxygen activation in metal-free macrocycles. Guided by density functional theory, we designed a tetra-aza macrocycle with nearly exclusive pyridinic nitrogen, distinct from the mixed-nitrogen environments of conventional porphyrins and phthalocyanines. This configuration uniquely stabilizes the key *OOH intermediate while strengthening interfacial electronic coupling with carbon supports. When integrated into a flow-cell electrolyzer, the catalyst achieves ∼95% H2O2 Faradaic efficiency and stability for over 800 h at 300 mA cm-2, continuously generating >3 wt.% H2O2. Furthermore, in situ generated reactive oxygen species enable selective ambient upgrading of furfural to oxime (>90% yield). Techno-economic analysis supports the economic viability of the process. By linking well-defined nitrogen coordination to scalable device performance, this work provides a blueprint for translating molecular precision into practical electrocatalytic manufacturing.