Refining Metal-Free\nCarbon Nanoreactors through Electronic\nand Geometric Comodification for Boosted H<sub>2</sub>O<sub>2</sub> Electrosynthesis toward Efficient Water Decontamination

Hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) electrosynthesis\nusing metal-free carbon materials via the 2e<sup>–</sup> oxygen\nreduction pathway has sparked considerable research interest. However,\nthe scalable preparation of carbon electrocatalysts to achieve satisfactory\nH<sub>2</sub>O<sub>2</sub> yield in acidic media remains a grand challenge.\nHere, we present the design of a carbon nanoreactor series that integrates\nprecise O/N codoping alongside well-regulated geometric structures\ntargeting high-efficiency electrosynthesis of H<sub>2</sub>O<sub>2</sub>. Theoretical computations reveal that strategic N/O codoping facilitates\npartial electron transfer from C sites to O sites, realizing electronic\nrearrangement that optimizes C-site adsorption of *OOH. Concurrently,\nthe O–O bond in *OOH is strengthened by charge transfer from\nantibonding to π-orbitals, stabilizing the O–O bond and\npreventing its dissociation. The carbon nanoreactor with a hollow\nbowl geometry also facilitates the mass transport of O<sub>2</sub> and H<sub>2</sub>O<sub>2</sub>, achieving an H<sub>2</sub>O<sub>2</sub> selectivity of 96% in acidic media. Furthermore, a flow cell\nintegrated with the refined nanoreactor catalyst achieves an impressive\nH<sub>2</sub>O<sub>2</sub> production rate of 2942.4 mg L<sup>–1</sup> h<sup>–1</sup>, coupled with stable operation of nearly 80\nh, surpassing the state-of-the-art metal-free analogs. The feasibility\nof the electro-synthesized H<sub>2</sub>O<sub>2</sub> is further demonstrated\nto be highly efficient in wastewater remediation.