Fabrication of - Heterostructured Photocatalysts with Triazine-Based Covalent Organic Framework and CuInS for High-Efficiency CO Reduction.

The application of covalent organic frameworks (COFs) for the photocatalytic reduction of CO is mostly limited by severe charge recombination and low sunlight utilization. Herein, a triazine-based COF with an electron-rich and large π-conjugated system (TCOF) was employed as a building block and integrated with CuInS (CIS) to construct a noble-metal-free and high-efficiency photocatalyst for CO reduction. The in situ growth of CIS nanosheets on TCOF creates a - heterojunction, named CIS@TCOF. Compared with TCOF, the CIS@TCOF heterostructure exhibits a dramatically boosted photocatalytic performance in the reduction of CO. The produced HCOOH yield over 10 wt % CIS@TCOF can be up to 171.2 μmol g h under visible light irradiation with good reproducibility, which is about 3 times as high as that over TCOF. Further in-depth studies indicate that the introduction of CIS not only enhances the visible light utilization but also restrains the recombination of photogenerated electron-hole pairs efficiently and facilitates the photoinduced charge transfer via the - heterojunction system due to the unique structural and compositional features. This research shows the great potential of COFs as efficient photocatalytic carbon fixation materials and provides a versatile route to construct semiconductor-COF heterostructures for photocatalysis.