Synergistic multi-heteroatom doping in carbon nitride: Harnessing a giant built-in electric field for enhanced photocatalytic H₂O₂ generation

Efficient separation and rapid migration of photogenerated charges are crucial for achieving high photocatalytic H₂O₂ production. In this study, a K, P, and O co-doped carbon nitride (KPOCN- x ) was synthesized through simple one-pot polymerization for efficient photocatalytic H₂O₂ production. The synergistic doping of metal and non-metal elements enhances light absorption and simultaneously promotes both in-plane and interplane photogenerated charge transfer. Induced by multi-heteroatom doping, especially the form of K bridging, the built-in electric field of KPOCN-5 increases up to 2.27 times that of undoped polymeric carbon nitride (Bulk CN), facilitating the efficient separation of photogenerated charges. Meanwhile, the rod-shaped structure shortens the migration distances of photogenerated charges, further promoting electron transfer and minimizing recombination. As a result, the H₂O₂ production rate of KPOCN-5 reached 3306.6 μmol g −1 h −1 under visible light, approximately 50 times higher than that of Bulk CN. This work highlights the construction of a giant built-in electric field as a powerful strategy for boosting the photocatalytic production of H₂O₂.