Silver frameworks based on a tetraphenylethylene-imidazole ligand for electrocatalytic reduction of CO₂ to CO

Metal-organic frameworks (MOFs) can be used as electrocatalysts for the CO₂ reduction reaction (CO₂RR) because of their well-dispersed metal centers. Silver is a common electrocatalyst for reduction of CO₂ to CO. In this study, two Ag-MOFs with different structures of [Ag₈O₂(TIPE)₆](NO₃)₄ (Ag-MOF1) and [Ag(TIPE)_0.5CF₃SO₃] (Ag-MOF2) [TIPE = 1,1,2,2-tetrakis(4-(imidazol-1-yl)phenyl)ethene] were synthesized and used for CO₂ electroreduction. The results show that Ag-MOF2 is superior to Ag-MOF1 and exhibits high CO faradaic efficiency (FE) of 92.21% with partial current density of 29.51 mA cm^-2 at -0.98 V versus reversible hydrogen electrode (RHE). The FE_CO is higher than 80% in the potential range of -0.78 to -1.18 V. The difference may be caused by different framework structures leading to different electrochemical active surface areas and charge transfer kinetics. This study provides a new strategy for designing and constructing CO₂ electroreduction catalysts and provides potential ways for solving environmental and energy problems caused by excessive CO₂ emission.