Electrosynthesis of Hydrogen Peroxide through Selective Oxygen Reduction: A Carbon Innovation from Active Site Engineering to Device Design.

Electrochemical synthesis of hydrogen peroxide (H 2 O 2 ) through the selective oxygen reduction reaction (ORR) offers a promising alternative to the energy-intensive anthraquinone method, while its success relies largely on the development of efficient electrocatalyst. Currently, carbon-based materials (CMs) are the most widely studied electrocatalysts for electrosynthesis of H 2 O 2 via ORR due to their low cost, earth abundance, and tunable catalytic properties. To achieve a high 2e - ORR selectivity, great progress is made in promoting the performance of carbon-based electrocatalysts and unveiling their underlying catalytic mechanisms. Here, a comprehensive review in the field is presented by summarizing the recent advances in CMs for H 2 O 2 production, focusing on the design, fabrication, and mechanism investigations over the catalytic active moieties, where an enhancement effect of defect engineering or heteroatom doping on H 2 O 2 selectivity is discussed thoroughly. Particularly, the influence of functional groups on CMs for a 2e - -pathway is highlighted. Further, for commercial perspectives, the significance of reactor design for decentralized H 2 O 2 production is emphasized, bridging the gap between intrinsic catalytic properties and apparent productivity in electrochemical devices. Finally, major challenges and opportunities for the practical electrosynthesis of H 2 O 2 and future research directions are proposed.