Effective Modulation of Multifunctional Cu-Metal Organic Frameworks Coordination Structure for a Selective CH4 Production via CO2RR

Cu-MOFs have shown great potential as electrocatalysts for selective methane production through the carbon dioxide reduction reaction (CO 2 RR). However, achieving coordination-induced tuning over the desired coordination environment of multi-functional Cu-MOFs remains a challenge, which is closely related to regulating the surface binding energy with reactants. Here we develop a modulator-assisted synthesis method for fabricating nanosized Cu-aminoterephthalic acid (Cu-NH 2 BDC) MOFs, aiming to modify the coordination geometry, which leads to the regulation of charge transfer ability. By incorporating a trace amount of 2-methylimidazole (MIm), the crystallinity of Cu-NH 2 BDC can be improved compared to traditional synthesis, which can be attributed to the influence of the coordination environment within the MOFs. The modulation of electrochemical properties, including the redox potential for the evolution of Cu active species and charge transfer resistance, resulting from additional Cu oxidation state by the amino functional groups, contributed to the enhancement of CH 4 FE (63%) and partial current density (−53   mA   cm −2 ) in an H-type cell, while effectively suppressing the parasitic hydrogen evolution reaction. This modulator-assisted synthesis approach presents a promising strategy for optimizing the performance of Cu-NH 2 BDC electrocatalysts in CO 2 -to-CH 4 conversion, offering valuable insights into structural modifications and charge transfer processes involved in the reaction.