The Direct Air Synthesis of Hydrogen Peroxide Induced by The Giant Built-In Electric Field of Trz-CN

Graphitic carbon nitride (C₃N₄) has been identified as an optimal material for hydrogen peroxide (H₂O₂) photosynthesis, although its utility is hampered by a high photocarrier recombination rate. Herein, a novel carbon nitride material with a giant built-in electric field (BEF), Trz-CN, is synthesized through a hydrothermal-calcination tandem strategy. The giant BEF (4.8-fold) induced by the large dipole moment facilitated the efficient separation and directional migration of photogenerated carriers. Trz-CN exhibited an H₂O₂ production rate of 569.9 µmol·g^-1·h^-1 using O₂ as feedstock under visible light (λ > 420 nm), marking an impressive 11.2-fold enhancement compared to bulk C₃N₄. Utilizing air instead of pure O₂ as feedstock resulted in a trivial 1.6% decrease in the H₂O₂ generation by Trz-CN while maintaining a substantial production rate of 560.6 µmol·g^-1·h^-1. Notably, Trz-CN showcased a sterilization rate of 99.9% against Escherichia coli (E. coli) in natural seawater. Density functional theory (DFT) calculations revealed that incorporating a nitrogen-rich skeleton into the C₃N₄ enhanced its oxygen adsorption capacity and lowered the energy barrier for H₂O₂ formation. This leads to enhanced photocatalytic performance for H₂O₂ generation under ambient air conditions. Trz-CN provides a new exploratory idea for direct air synthesis of H₂O₂ and ballast water treatment.