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

Copper-based nanomaterials are attractive in CO 2 electroreduction into valuable chemicals but still suffer from limited selectivity of C 2+ 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 ((CH 3 O) 3 Si–) and trifluoromethyl (–CF 3 ) 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 C 2+ 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 –CF 3 and enhanced coverage of *CO. This work offers a new insight in tuning the electrocatalytic microenvironment through the surface polymerization process.