Organic Intercalation Enables Controllable Single-Atom Coordination for Efficient H₂O₂ Electrosynthesis

The electrochemical two-electron oxygen reduction reaction mediated by single-atom catalysts provides a sustainable and efficient route for on-site H₂O₂ production. Although heteroatom engineering of the first coordination sphere has been shown to effectively tune catalytic performance, existing strategies typically introduce heteroatoms through multistep processes, making it difficult to control the formation of the target coordination environment prior to pyrolysis. Herein, we propose an organic intercalation-driven precursor modulation strategy that pre-organizes coordinating atom sources to alter the thermodynamic preference for first-coordination-sphere formation during pyrolysis, enabling the preferential formation of the Co-N₃O/C coordination environment. This potentially generalizable strategy offers a controllable alternative to conventional multi-step post-synthetic modification by enabling in situ coordination engineering. The resulting Co-N₃O/C catalyst achieves an H₂O₂ selectivity of >99.0% and maintains stable operation for 120 h under ambient-air-fed conditions at a current density of 100 mA cm^-2, accumulating a 3.2 wt% H₂O₂ solution. Crucially, the local coordination structure indicates that O incorporation tunes the electronic structure and modulates *OOH adsorption, thereby kinetically favoring *OOH protonation over O─O bond cleavage. This work provides a potentially generalizable strategy for controlling first-coordination-sphere formation in single-atom catalysts and offers deep insights into coordination-mediated enhancement for industrial-scale H₂O₂ electrosynthesis.