Fig. 5: Performance of paired HPL-electrodes in membrane-free electrolyzer.

a Effect of current density (10, 20, 30, 40, and 50 mA cm⁻²) on H₂O₂ accumulation in membrane-free electrolyzer with 0.1 M Na₂SO₄ solution after 5 h operation. b H₂O₂ production using HPL-coated electrodes in membrane-free electrolyzer over 100 h continuous operation at 20 mA cm⁻². The inset of b shows the H₂O₂ concentration before and after 100 h operation by using the potassium titanium (IV) oxalate method. c Comparison of H₂O₂ production rate in membrane-free electrolyzer with the literature (H₂O₂ concentration at 1 h). The c inset zooms in the current density of c between 0 and 50 mA cm^–2 on the horizontal axis and 0–0.5 g L^–1 on the vertical axis. d Schematic illustration and e digital image of the solar-driven membrane-free electrolyzer for H₂O₂ electrosynthesis and disinfection. f Surface water sterilization of the solar-driven membrane-free electrolyzer. The inset of f shows the pictures of the flat colony of E. coli in effluent. g Cost comparison between traditional electrolyzer and membrane-free electrolyzer. The error bars in panels a and f represent the standard deviation and were calculated on the basis of at least three experimental data points. Source data for a, b, f, and g are provided as a Source Data file.