Enhanced photocatalytic synthesis of H2O2 by triplet electron transfer at g-C3N4@BN van der Waals heterojunction interface

Abstract

The van der Waals heterojunctions demonstrate exceptional advantages due to their outstanding charge separation capabilities and remarkable flexibility in tuning electronic properties. This study explores the potential application of the 2D/2D g-C₃N₄@BN van der Waals heterojunction in the photocatalytic synthesis of hydrogen peroxide (H₂O₂). Based on this heterojunction, we investigated the energy transfer process between triplet excitons and singlet oxygen, emphasizing the importance of catalyst structure for charge separation and the stable generation of triplet electrons. By constructing a charge transfer pathway, the built-in electric field within the heterojunction effectively drives the directional migration of charge carriers, significantly extending their lifetime. We employed two modification strategies to regulate the excited state electronic properties of the catalyst, including adjusting the interlayer arrangement to enhance charge transport capability and halogen modification to improve the light responsiveness of materials. Experimental validation indicates that the representative chlorinated-CN@BN effectively suppresses exciton recombination compared to CN, extending the lifetime of excited-state carriers by 3.52 times. Furthermore, the photocatalytic yield of H₂O₂ is improved by 2.73 times. This study provides a theoretical basis for developing novel photocatalysts and inspires the design of catalysts for direct synthesis of H₂O₂ from oxygen.