Research progress on carbon-based non-metallic nanomaterials as catalysts for the two-electron oxygen reduction for hydrogen peroxide production

The electrocatalytic two-electron oxygen reduction reaction (2e-ORR) is an effective, safe and green method to produce hydrogen peroxide (H₂O₂) as an alternative to the industrial anthraquinone process. Carbon-based nanomaterials with the advantages of high electrical conductivity, good structural stability, easy control of the nanostructure and low cost, are recognized as promising catalysts for H₂O₂ production by 2e-ORR. A detailed overview of the research progress on these carbon-based electrocatalysts, their intrinsic active centers and reaction mechanisms is helpful to obtain a comprehensive and systematic understanding of the latest progress in this field. Fundamental aspects and mechanisms of the two-electron and four-electron pathways for the ORR are introduced, followed by a comprehensive review of strategies to modify carbon-based nanomaterials such as single, dual or multiple heteroatom doping, defect design and surface modification, in order to obtain high activity and selectivity for H₂O₂ synthesis. Finally, the prospects and challenges in obtaining catalysts with high rate and yield are presented, which should shed light on future scientific research and their use for H₂O₂ synthesis.