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.