Construction of covalent organic framework and g-C3N4 heterojunction for photocatalytic degradation of tetracycline and photocatalytic production of hydrogen peroxide

Organic semiconductors, notably graphitic carbon nitride (g-C3N4, CN), are increasingly recognized as effective photocatalysts for environmental remediation and energy harvesting. In this study, we introduce a Van der Waals metal-free heterojunction (TTO/CN), composed of g-C3N4 and a vinyl-linked covalent organic framework (COF), fabricated via a simple self-assembly process. This novel heterojunction is adeptly utilized for the photocatalytic degradation of tetracycline (TC) in aqueous environments and for the generation of hydrogen peroxide (H2O2). The synthesized TTO/CN heterojunction demonstrates an expanded specific surface area and broadened absorption spectrum in the visible light range, coupled with enhanced efficiency in photogenerated carrier separation and transfer. These attributes collectively contribute to its remarkable photocatalytic performance. Notably, the TTO/CN-1 variant emerges as a highly efficient photocatalyst, exhibiting degradation rate constants for TC that surpass those of TTO-COF and CN by 2.0 and 6.2 times, respectively. Furthermore, TTO/CN-1 distinguishes itself as a dual-functional photocatalyst, showcasing exceptional activity in H2O2 production (745.3 μM·h−1, or 1863.3 μmol·g−1·h−1). This research heralds a potent strategy for the design and synthesis of van der Waals heterojunction photocatalysts, and the distinctive heterostructures of COF and CN hold significant promise for enhancing the performance and broadening the applicability of CN-based photocatalysts.