Dual-Mechanism Study of Metal-Free g-C₃N₄ Catalysts for Advanced Oxidation Under Non-Photocatalytic Conditions

Metal-free materials have been proved to be promising replacements of traditional metal-based catalysts for advanced oxidation reactions. Carbon nitride was found to be able to activate H₂O₂ and generate hydroxyl radicals (•OH). Nevertheless, the performance of carbon nitride is highly dependent on an external light source. In this work, we report a light-independent, metal-free catalyst based on g-C₃N₄ prepared using a facile calcination method. It is revealed that two reaction pathways, a radical (•OH) one and a nonradical (H₂O₂) one, coexist in organics oxidation on g-C₃N₄. The dominant reaction pathway is dependent on the condensation temperature of UCN. In addition, this g-C₃N₄ exhibited excellent stability after being recycled and reused for five cycles. The findings in this work can be used for the design of efficient and robust metal-free catalysts with both superior catalytic performance and high stability for various heterogeneous catalytic processes.