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.