Mesoporous Boron-Doped Carbon with Curved B4C Active Sites for Highly Efficient H2O2 Electrosynthesis in Neutral Media and Air-Supplied Environments

Abstract

Hydrogen peroxide (H₂O₂) electrosynthesis via the 2e⁻ oxygen reduction reaction (ORR) is considered as a cost-effective and safe alternative to the energy-intensive anthraquinone process. However, in more practical environments, namely, the use of neutral media and air-fed cathode environments, slow ORR kinetics and insufficient oxygen supply pose significant challenges to efficient H₂O₂ production at high current densities. In this work, mesoporous B-doped carbons with novel curved B₄C active sites, synthesized via a carbon dioxide (CO₂) reduction using a pore-former agent, to simultaneously achieve excellent 2e⁻ ORR activity and improved mass transfer properties are introduced. Through a combination of experimental analysis and theoretical calculations, it is confirmed that the curved B₄C configuration, formed by mesopores in the carbon, demonstrates superior selectivity and activity for 2e⁻ ORR due to its weaker interaction with *OOH intermediates compared to planar B₄C in neutral media. Moreover, the mesopores facilitate oxygen supply and suppress the hydrogen evolution reaction, achieving a Faradaic efficiency of 86.2% at 150 mA cm⁻² under air-supplied conditions, along with an impressive O₂ utilization efficiency of 93.6%. This approach will provide a route to catalyst design for efficient H₂O₂ electrosynthesis in a practical environment.