Molecular engineering of covalent triazine frameworks for highly enhanced photocatalytic aerobic oxidation of sulfides

Abstract

Conjugated porous organic polymers have emerged as promising candidates for photocatalytic applications on account of their diverse designability and tunability in structure and function. In order to enhance the photocatalytic activity of conjugated porous organic polymers, organic electron donor and acceptor moieties constituting their backbones are typically employed to promote efficient charge separation and transfer. Here we present the fine-tuning band structures of three covalent triazine frameworks (CTFs) by integrating various electron-donating units into their polymeric skeletons. Among them, the newly designed CTF containing the phenothiazine moiety reveals extended absorption in the visible light region as well as enhanced charge separation/transfer efficiency, thereby giving rise to a remarkably increased photocatalytic performance as exemplified by the selective aerobic oxidation of sulfides to sulfoxides under visible light and air. This study will offer a valuable insight into the structural design of CTF based polymeric photocatalysts at the molecular level.