Membrane-free Electrolysis Production of Hydrogen Peroxide on Low-cost Metal-free Electrocatalysts for Dye Degradation

The efficient production of hydrogen peroxide (H₂O₂) solution was achieved by combining cathodic two-electron oxygen reduction (2e⁻ ORR) and anodic two-electron water oxidation (2e⁻ WOR) in two half-reaction cells. h-BN loaded on carbon fibers (h-BN@C) is prepared and employed as an anode material to catalyze 2e⁻ WOR, while sulfonated commercial BP-2000 carbons (BP-2000-SO₃H) were prepared as the cathode materials for 2e⁻ ORR. In a 2 M KHCO₃ solution, an overall Faradaic efficiency of 97 % and a total H₂O₂ production rate of 1872 mmol g⁻¹ h⁻¹ over metal-free electrodes were accomplished in a membrane-free flow cell. The dilute H₂O₂ solution could be directly used to degrade Rhodamine B, methyl blue and methylene orange dyes in water. This work proved low-cost production of dilute H₂O₂ solution in simple membrane-free flow cells with single electrolyte and on-site utilization for efficient dye degradation.