Radiation-Synthesized Metal-Organic Frameworks with Ligand-Induced Lewis Pairs for Selective CO₂ Electroreduction

The electrochemical activation of inert CO₂ molecules through C─C coupling reactions under ambient conditions remains a significant challenge but holds great promise for sustainable development and the reduction of CO₂ emission. Lewis pairs can capture and react with CO₂, offering a novel strategy for the electrosynthesis of high-value-added C2 products. Herein, an electron-beam irradiation strategy is presented for rapidly synthesizing a metal-organic framework (MOF) with well-defined Lewis pairs (i.e., Cu- N_pyridinic). The synthesized MOFs exhibit a total C2 product faradic efficiency of 70.0% at -0.88 V versus RHE. In situ attenuated total reflection Fourier transform infrared and Raman spectra reveal that the electron-deficient Lewis acidic Cu sites and electron-rich Lewis basic pyridinic N sites in the ligand facilitate the targeted chemisorption, activation, and conversion of CO₂ molecules. DFT calculations further elucidate the electronic interactions of key intermediates in the CO₂ reduction reaction. The work not only advances Lewis pair-site MOFs as a new platform for CO₂ electrochemical conversion, but also provides pioneering insights into the underlying mechanisms of electron-beam irradiated synthesis of advanced nanomaterials.