Highly Perfluorinated Covalent Triazine Frameworks Derived from a Low‐Temperature Ionothermal Approach Towards Enhanced CO<sub>2</sub> Electroreduction
Xian Suo, Fengtao Zhang, Zhenzhen Yang, Hao Chen, Tao Wang, Zongyu Wang, Takeshi Kobayashi, Chi‐Linh Do‐Thanh, Dmitry S. Maltsev, Zhimin Liu, Sheng Dai
Abstract
Abstract 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 ZnCl 2 ‐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 °C). Fabricating F‐CTFs with high fluorine contents (>30 wt %) remains challenging. Herein, we present a low‐temperature ionothermal approach (275 °C) to prepare F‐CTFs, which is achieved via polymerization of tetrafluoroterephthalonitrile (TFPN) over the Lewis superacids, e.g., zinc triflimide [Zn(NTf 2 ) 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 CO 2 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.