Carboxylated Hexagonal Boron Nitride/Graphene Configuration for Electrosynthesis of High-Concentration Neutral Hydrogen Peroxide

The electrosynthesis of hydrogen peroxide (H₂O₂) via two-electron (2e⁻) oxygen (O₂) reduction reaction (ORR) has great potential to replace the traditional energy-intensive anthraquinone process, but the design of low-cost and highly active and selective catalysts is greatly challenging for the long-term H₂O₂ production under industrial relevant current density, especially under neutral electrolytes. To address this issue, this work constructed a carboxylated hexagonal boron nitride/graphene (h-BN/G) heterojunction on the commercial activated carbon through the coupling of B, N co-doping with surface oxygen groups functionalization. The champion catalyst exhibited a high 2e⁻ ORR selectivity (>95 %), production rate (up to 13.4 mol g⁻¹ h⁻¹), and Faradaic efficiency (FE, >95 %). The long-term H₂O₂ production under the high current density of 100 mA cm⁻² caused the cumulative concentration as high as 2.1 wt %. The combination of in situ Raman spectra and theoretical calculation indicated that the carboxylated h-BN/G configuration promotes the adsorption of O₂ and the stabilization of the key intermediates, allowing a low energy barrier for the rate-determining step of HOOH* release from the active site and thus improving the 2e⁻ ORR performance. The fast dye degradation by using this electrochemical synthesized H₂O₂ further illustrated the promising practical application.