Boosting Electroreduction of CO2 over Cationic Covalent Organic Frameworks: Hydrogen Bonding Effects of Halogen Ions

We present the first example of charged imidazolium functionalized porphyrin-based covalent organic framework (Co-iBFBim-COF-X) for electrocatalytic CO2 reduction reaction, where the free anions (e.g., F-, Cl-, Br-, and I-) of imidazolium ions nearby the active Co sites can stabilize the key intermediate *COOH and inhibit hydrogen evolution reaction. Thus, Co-iBFBim-COF-X exhibits higher activity than the neutral Co-BFBim-COF, following the trend of F-

Automated summary

We present the first example of a charged imidazolium functionalized porphyrin-based covalent organic framework for electrocatalytic CO2 reduction reaction. The free anions of imidazolium ions nearby the active sites can stabilize the key intermediate and inhibit hydrogen evolution reaction. Thus, the charged imidazolium functionalized covalent organic framework exhibits higher activity than the neutral version and follows a trend depending on the anion.