Conversion of CO₂ to defective porous carbons in one electro-redox cycle for boosting electrocatalytic H₂O₂ production

Conversion of CO₂ to catalytically active carbons for electrochemical synthesis of hydroxide peroxide (H₂O₂) is highly desirable to replace the energy-intensive anthraquinone process, and achieve carbon utilization and emission reduction. Here, we develop an electrochemical reduction-reoxidation strategy in the in-situ conversion of absorbed CO₂ to defective porous carbons (DPCs) for boosting H₂O₂ production. By rationally varying oxidation conditions, hole and edge defects were controllably created on CO₂-derived carbons. Moreover, the defects dramatically enhanced the activity and selectivity toward the 2e^- oxygen reduction reaction (ORR). DPC0.5–5 obtained by electro-oxidizing the CO₂-derived carbon has edge and hole defects, delivering the H₂O₂ selectivity greater than 90%. By means of density functional theory calculations, the essential role of defects is demonstrated, and the types of defects with high activity are identified. The approach presented here not only sheds light on the value-added utilization of CO₂, but also develops the defect engineering of carbon materials.