Abstract
The electrochemical two-electron oxygen reduction reaction (2e
−
ORR) for the production of hydrogen peroxide (H
2
O
2
) 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 H
2
O
2
electrosynthesis, particularly in acidic media. Herein, we designed and synthesized cobalt species incorporated in oxygen-rich mesoporous carbon nanosheets (MesoC-Co), resulting in electrochemical H
2
O
2
production with a selectivity above 80% over a wide potential range in 0.10 M HClO
4
. 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 H
2
O
2
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 H
2
O
2
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.