Imidazolium‐Functionalized Cationic Covalent Triazine Frameworks Stabilized Copper Nanoparticles for Enhanced CO2 Electroreduction

Abstract The highly selective production of reduced multicarbon products with long‐term durability for CO 2 electroreduction reaction (CO 2 RR) using clean and renewable electricity is currently a major challenge. Copper nanoparticles (Cu NPs) are exceptionally advantageous for CO 2 RR to yield multielectron transfer chemical products such as ethylene and ethanol. However, Cu NPs for CO 2 RR generally require high overpotential to produce multiple electron transfer C 2+ products with poor stability. Herein, an imidazolium‐functionalized covalent triazine framework (ICTF) stabilized Cu NPs (Cu/ICTF) for the enhanced CO 2 RR to produce ethylene is reported. The imidazolium groups in the cationic ICTF not only can enhance CO 2 capture capacity and lower the energetic barrier to activate CO 2 , but also the in situ formed N‐heterocyclic carbenes (NHC) could stabilize Cu NPs to prevent their deactivation. Thus, the Cu/ICTF demonstrated higher selectivity (35 %) for the electroreduction of CO 2 to ethylene with larger partial current density of ethylene (4.14 mA cm −2 ) over the unmodified neutral CTF stabilized Cu NPs (Cu/CTF) with 29 % Faradaic efficiency (FE) of ethylene and current density of 3.69 mA cm −2 . Moreover, the active sites could be stabilized by the in situ produced NHC in ICTF and the current density and C 2 H 4 FE of Cu/ICTF 50 were almost maintained after 10 h continuous electrolysis experiment, while the C 2 H 4 FE of Cu/CTF 50 were lost ca. 42 % of its original value after 7 h. This strategy provides a facile approach to stabilize active sites for CO 2 RR and may bring new inspiration to apply in energy storage and conversion.