Chlorine-mediated photocatalytic hydrogen production based on triazine covalent organic framework

Covalent triazine-based frameworks (CTFs), as a type of 2D conjugated polymer, have attracted keen attention because of the promising visible-light-driven photocatalytic performance for water splitting. Nonetheless, amelioration on the configuration and electronic microstructure of CTFs for enhanced photocatalytic performance is still challenging and anticipated. Herein, we developed a new strategy to synthesize visible-light-driven Cl-intercalated CTF-1 photocatalysts (labeled as Cl-ECF) via a ball-milling exfoliation-assisted acidification method. Many characterizations confirm the formation of Cl-C and Cl-N bonds in the Cl-ECF. The effects of the Cl-intercalation on the crystal structure, microstructure and charge transfer behaviors of CTF-1 were systematically studied by various characterizations and DFT calculation. The results revealed that Cl-ECF exhibited significantly promoted charge transfer, narrowed bandgap and enhanced photocatalytic activity of H-2 production because Cl-C and Cl-N covalent bonds can form covalently interlayer channels in the Cl-ECF. The as-prepared Cl-ECF shows a hydrogen production rate of 1.296 mmol.g(-1) h(-1) under visible light irradiation, which is 2.2 times higher than that of CTF-1. This work could provide new insights into the new approach of intercalation modification to improve photocatalytic performance of 2D layered photocatalysts.