Solar-driven seawater production H₂O₂ catalyzed by hydroxyl functionalized crystalline K-doped g-C₃N₄ under ambient conditions

Three hydroxyl functionalized crystalline K-doped g-C₃N₄ were synthesized from dicyandiamide, melamine, ammonium chloride, ammonium oxalate, and ammonium citrate via ionothermal polycondensation using KCl as molten salt under N₂ atmosphere, which served as efficient recyclable photocatalysis realized that generating H₂O₂ directly from seawater with air by 2e⁻ ORR pathway under stimulated solar irradiation in ambient conditions. Under optimized conditions, the highest H₂O₂ production rate of 1622 μmol g⁻¹ h⁻¹ for duration of 10 h was obtained. The cycling performances of HPCN-2 displayed reusable for five times without noticeably loss of its catalytic activity. This work presents a real safer, sustainable, and economical approach for production of H₂O₂ directly from abundant natural seawater.