Fabrication of superhydrophilic porous carbon materials through a porogen-free method: Surface and structure modification promoting the two-electron oxygen reduction activity.

HYPOTHESIS:Electrochemical manufacture of H2O2 through the two-electron oxygen reduction reaction (2e- ORR), providing prospects of the distributed production of H2O2 in remote regions, is considered a promising alternative to the energy-intensive anthraquinone oxidation process. EXPERIMENTS:In this study, one glucose-derived oxygen-enriched porous carbon material (labeled as HGC500) is developed through a porogen-free strategy integrating structural and active site modification. FINDINGS:The superhydrophilic surface and porous structure together promote the mass transfer of reactants and accessibility of active sites in the aqueous reaction, while the abundant CO species (e.g., aldehyde groups) are taken for the main active site to facilitate the 2e- ORR catalytic process. Benefiting from the above merits, the obtained HGC500 possesses superior performance with a selectivity of 92 % and mass activity of 43.6 A gcat-1 at 0.65 V (vs. RHE). Besides, the HGC500 can operate steadily for 12 h with the accumulation of H2O2 reaching up to 4090±71 ppm and a Faradic efficiency of 95 %. The H2O2 generated from the electrocatalytic process in 3 h can degrade a variety of organic pollutants (10 ppm) in 4-20 min, displaying the potential in practical applications.