Highly Perfluorinated Covalent Triazine Frameworks Derived from a Low-Temperature Ionothermal Approach Towards Enhanced CO2 Electroreduction

Perfluorinated covalent triazine frameworks (F-CTFs) have shown unique features and attractive performance in separation and catalysis. However, state-of-the-art F-CTFs synthesized via the ZnCl2-promoted procedure have quite low fluorine contents due to C-F bond cleavage induced by chloride (a Lewis base) and the harsh conditions deployed (400-700 degrees C). Fabricating F-CTFs with high fluorine contents (>30 wt %) remains challenging. Herein, we present a low-temperature ionothermal approach (275 degrees C) to prepare F-CTFs, which is achieved via polymerization of tetrafluoroterephthalonitrile (TFPN) over the Lewis superacids, e.g., zinc triflimide [Zn(NTf2)(2)] without side reactions. With low catalyst loading (equimolar), F-CTFs are afforded with high fluorine content (31 wt %), surface area up to 367 m(2) g(-1), and micropores around 1.1 nm. The highly hydrophobic F-CTF-1 exhibits good capability to boost electroreduction of CO2 to CO, with faradaic efficiency of 95.7 % at -0.8 V and high current density (-141 mA cm(-2)) surpassing most of the metal-free electrocatalysts.

Automated summary

A low-temperature ionothermal approach is utilized to prepare F-CTFs with high fluorine content and excellent performance. The highly hydrophobic F-CTF-1 shows promising capability in electroreduction of CO2 to CO.