Trinuclear Cu(I) Metal-Organic Framework Inspires the Activation of *CO2 Via Electrostatic Tension to Boost the Electrochemical Conversion of CO2-to-Methanol.

The metal-organic frameworks (MOFs) as favorable candidates, are applied to the reduction reaction of CO2 due to the unique affinity for CO2 molecules and abundant monometallic active sites. However, most MOF-based electrocatalysts require a carbonization process to overcome their potentially poor conductivity and inert catalytic activity. Here, a semiconducting trinuclear Cu(I)-MOF undergone low-temperature activation (CuTz-1-300) is directly employed as an electrocatalyst for producing methanol. The CuTz-1-300 achieves a methanol faradaic efficiency of 56.41% at the working potential of -0.97 V versus the reversible hydrogen electrode in 0.5 m KHCO3 electrolyte. The experiments and DFT calculations imply that the generation of *COOH is the rate-determining step for methanol, and *CO prefers to be further reduced instead of releasing as a CO product. Specifically, the unique CuN3 is correspond to nearby BF4, - producing subtle synergistic electronic effects that CO2 binding with a relatively strong C···F interaction to BF4 - and weak C─H···O interactions from phenyl groups to enhance the localized CO2 concentration by electrostatic tension. This work demonstrates the use of ionic MOF with positive univalent Cu to improve the efficiency of electrocatalytic CO2 reduction.