Refining Metal-Free Carbon Nanoreactors through Electronic and Geometric Comodification for Boosted H₂O₂ Electrosynthesis toward Efficient Water Decontamination

Hydrogen peroxide (H₂O₂) electrosynthesis using metal-free carbon materials via the 2e^- oxygen reduction pathway has sparked considerable research interest. However, the scalable preparation of carbon electrocatalysts to achieve satisfactory H₂O₂ yield in acidic media remains a grand challenge. Here, we present the design of a carbon nanoreactor series that integrates precise O/N codoping alongside well-regulated geometric structures targeting high-efficiency electrosynthesis of H₂O₂. Theoretical computations reveal that strategic N/O codoping facilitates partial electron transfer from C sites to O sites, realizing electronic rearrangement that optimizes C-site adsorption of *OOH. Concurrently, the O-O bond in *OOH is strengthened by charge transfer from antibonding to π-orbitals, stabilizing the O-O bond and preventing its dissociation. The carbon nanoreactor with a hollow bowl geometry also facilitates the mass transport of O₂ and H₂O₂, achieving an H₂O₂ selectivity of 96% in acidic media. Furthermore, a flow cell integrated with the refined nanoreactor catalyst achieves an impressive H₂O₂ production rate of 2942.4 mg L^-1 h^-1, coupled with stable operation of nearly 80 h, surpassing the state-of-the-art metal-free analogs. The feasibility of the electro-synthesized H₂O₂ is further demonstrated to be highly efficient in wastewater remediation.