Mesoporous Co–O–C nanosheets for electrochemical production of hydrogen peroxide in acidic medium.

The electrochemical two-electron oxygen reduction reaction (2e⁻ ORR) for the production of hydrogen peroxide (H₂O₂) enables a promising electro-Fenton process for on-site and on-demand environmental remediation. However, there is still a lack of low-cost electrocatalysts for efficient H₂O₂ electrosynthesis, particularly in acidic media. Herein, we designed and synthesized cobalt species incorporated in oxygen-rich mesoporous carbon nanosheets (MesoC-Co), resulting in electrochemical H₂O₂ production with a selectivity above 80% over a wide potential range in 0.10 M HClO₄. In our reported electrocatalysts, atomic Co sites contribute to the high ORR activity of carbon-based materials in an acidic medium, and the oxygen-containing functional groups and mesoporous structure endow the catalysts with high H₂O₂ selectivity. The ORR current density over MesoC-Co with uniform mesopores and well-defined Co species reaches −1 mA cm⁻² at 0.4 V versus reversible hydrogen electrode with very good durability. In addition, the cumulative concentration of H₂O₂ is 7.2 mmol L⁻¹ within 24 h, allowing for the effective electro-Fenton degradation of organic pollutants. Our results might shed light on the design of catalytic systems for sustainable electro-Fenton processes. [ABSTRACT FROM AUTHOR]