Oxygen Enrichment on Carbon Nanoreactors and *OOH Modulation on Sn1 Sites Cooperatively Promote Industrial-Scale H2O2 Electrosynthesis.

Industrial‑scale H2O2 electrosynthesis faces two major challenges: oxygen depletion at the catalytic interface, which causes diffusion limitations, and a strong dependence of product selectivity on the adsorption behavior of the *OOH intermediate. Constructing an O2‑enriched microenvironment alleviates transport issues, while tuning *OOH adsorption prevents excessive O─O bond cleavage; their synergy is expected to boost ORR performance. Guided by theory, we developed a Sn single‑atom-anchored hollow mesoporous carbon nanoreactor (Sn1/HMCS). The hollow mesoporous carbon nanoreactor facilitates an oxygen‑enriched microenvironment at the catalytic interface via spontaneous O2 adsorption and diffusion, while the N/O‑coordinated Sn sites enable optimal *OOH adsorption regulation, delivering ∼100% H2O2 selectivity. The adaptive matching between the spontaneous oxygen supply kinetics and the electrocatalytic reaction allows the system to maintain both optimal thermodynamic potential and high selectivity at industrially relevant high‑current conditions. Assembling Sn1/HMCS in a solid‑electrolyte cell delivered an industrial‑scale system for high‑purity H2O2 with low energy consumption and excellent stability. At 500 mA cm- 2, it produced ∼4.51 wt% H2O2 at a rate of 31.8 mol gcatalyst - 1 h- 1, with stable operation over 300 h. This work provides a practical way to prepare catalysts meeting industrial‑scale current density requirements and facilitates the development of economically feasible H2O2 electrosynthesis schemes.