Platinum single-atoms anchored covalent triazine framework for efficient photoreduction of CO2 to CH4

Achieving maximum atom-utilization efficiency is desirable to facilitate the charge separation and CO2 activation for photocatalytic CO2 reduction. Herein, we report a well-defined positioned synthesis of Pt single atoms in ethylene glycol (EG)-modified covalent triazine framework (Pt-SA/CTF-1) via a photo-deposition method for efficient photoreduction CO2 to CH4 under visible light irradiation. The well-defined coordination structure of Pt-N(C) sites in the Pt-SA/CTF-1 catalyst has been probed by HAADF-STEM and EXAFS. Results show that Pt single atoms confined into CTF-1 not only improved CO2 adsorption and activation but also accelerated the separation and transfer of photogenerated carriers in CTF-1. Consequently, Pt-SA/CTF-1 exhibited superior photoactivity and stability, which significantly surpass the Pt nanoparticles-based CTF-1, affording CH4 as the main reduction product. This work showcases an operable avenue to develop single-metal-atom photocatalysts and a mechanistic insight into photoreduction of CO2 by CTF-based composite.