Organic Sodium Salt‐Assisted Synthesis of Multi‐Defective Highly Dense Structural Carbon Nitride for Efficient Photocatalytic H ₂ O ₂ Production

The construction of multi-defective highly dense structural CN with a large surface area has shown great promise in photosynthesis of H₂O_2, whereas there remains a great challenge. In the present work, a novel and facile approach is proposed to prepare porous carbon nitride (CN) enriched with cyano groups, nitrogen vacancies, sodium doping, and oxygen-containing functional groups by pre-constructing sodium-containing supramolecular precursors under the assistance of sodium dichloroisocyanurate (DCCNa) with subsequent pyrolysis, which integrates the merits of alkali-metals-assisted pyrolysis and supramolecular structures. Such multi-defective features not only improve the visible light absorption capacity and oxygen reduction ability but also facilitate efficient separation and transfer of photo-generated electrons and holes, which is beneficial to enhance its photocatalytic performance for H₂O₂ production. The optimal CN-DCCNa_0.5 exhibits a high H₂O₂ yield of 1032.8 µm within 4 h, which is 8.32 times higher than pristine CN (123.2 µm). This study provides new insights into optimizing CN-based photocatalysts for efficient and green photocatalytic H₂O₂ synthesis.