Visible light-driven hydrogen production using an imine-based hybrid covalent organic framework with triazine and sulfone amine linkers

The design of novel semiconducting photocatalysts is crucial for hydrogen production using sunlight. Covalent organic frameworks (COFs), which are porous materials formed solely by the covalent bonding of light elements, have garnered significant attention as efficient photocatalysts. However, common COFs face challenges related to visible light absorption, the recombination rate of electron-hole pairs, and hydrogen production activity. In this study, we successfully synthesized a 1,3,5-Triformylphloroglucinol (TP) -based hybrid COF {(TP-TTA/TP-TSN)-COF}, using a simple hydrothermal method, incorporating two amine linkers: 4,4',4''-(1,3,5-triazine-2,4,6-triyl) trianiline (TTA) and 3,7-diamino-2,8-dimethyldibenzothiophenesulfone (TSN). This hybrid COF exhibits excellent optical and electrochemical properties due to the large electron transport characteristics of the triazine ring and the electron-withdrawing nature of the sulfonic group. It achieved a hydrogen production rate of 2200 μmol g⁻¹ h⁻¹, approximately twice that of conventional TP-TTA-COF (980 μmol g⁻¹ h⁻¹) and TP-TSN-COF (1100 μmol g⁻¹ h⁻¹). This study presents an effective strategy for enhancing the photocatalytic activity of COF-based materials.