Functionalizing Cu nanoparticles with fluoric polymer to enhance C2+ product selectivity in membraned CO2 reduction

Copper-based nanomaterials are attractive in CO2 electroreduction into valuable chemicals but still suffer from limited selectivity of C2+ products due to the parasitic hydrogen evolution reaction and inefficient dimerization of absorbed CO intermediate (⁎CO). Herein, we report an in situ polymerization strategy to coat hydrophobic polymer containing methoxyl silane ((CH3O)3Si–) and trifluoromethyl (–CF3) functional groups on Cu nanoparticles. The optimized Cu-poly exhibits a high Faradaic efficiency of 71.08% and a remarkable partial current density of 355.4 mA cm−2 for C2+ products in a membrane electrode assembly electrolyzer using a bicarbonate electrolyte. A combined study of density functional theory calculations and in situ infrared characterizations indicates that the enhanced performances could be ascribed to the decreased formation energy of ⁎COCOH, induced by the withdraw-electron effect of –CF3 and enhanced coverage of ⁎CO. This work offers a new insight in tuning the electrocatalytic microenvironment through the surface polymerization process.