Combined Cathodic and Anodic Hydrogen Peroxide Electrosynthesis Over Mesoporous Carbon-Doped Boron Nitrides

By pairing two-electron oxygen reduction (2e-ORR) at cathodes and two-electron water oxidation reaction (2e-WOR) at anodes, hydrogen peroxide (H2O2) solution could be simultaneously produced in two half-reaction cells. But it was challenged by short of efficient electrocatalysts with the matched current density. In this work, mesoporous carbon-doped boron nitrides (C-doped BN) prepared by annealing organic resin polymer/silica in NaBH4 and NaNH2 inorganic salts were found to be efficient metal-free bifunctional electrocatalyst for both 2e-ORR and 2e-WOR. It could efficiently catalyze 2e-ORR to H2O2 in 0.2 M H3PO4 acidic electrolytes with higher Faraday efficiency of about 77% in half reaction, while it was very active for 2e-WOR to H2O2 in 2 M KHCO3 with 7.4 μmol cm-2 min-1 in half reaction. When pairing them in one H-type cell, H2O2 solution could be totally produced over C-doped BN in both anode and cathode cells. The C-doped BN not only served an effective bifunctional electrocatalyst for 2e-ORR and 2e-WOR, but also testified a possible pair electrosynthesis method for H2O2 based on the efficient metal-free electrocatalyst.