Compensating the impurities on the Cu surface by MOFs for enhanced hydrocarbon production in the electrochemical reduction of carbon dioxide

Copper(Cu)provides a cost-effective means of producing value-added fuels through the electrochemical reduction of carbon dioxide(CO_(2)RR).However,we observed the production of hydrocarbons via CO_(2)RR on commercial Cu films is less efficient because of the surface impurities,i.e.,Fe.Carbon monoxide(CO),a reaction intermediate of CO_(2)RR to hydrocarbons,binds strongly to the Fe sites and interrupts the production of hydrocarbons,resulting in an active hydrogen evolution reaction(HER).Herein,we report a method of blocking the effect of Fe impurities on the Cu surface through the preferential growth of nano-sized metal-organic frameworks(MOFs)on Fe site.When zirconium(Zr)-based MOFs(UiO-66)forms a compensating layer on Cu film via the terephthalic acid(TPA)-Fe coordination bond,the Ui O-66 coated Cu film(UiO-66@Cu)presents significantly improved hydrocarbon Faradaic efficiency(FE)of 37.59%compared to 14.68%FE on commercial Cu film(99.9%purity)by suppressing HER.According to X-ray photoelectron spectroscopy(XPS)analysis,the UiO-66 ligand binds to entire metallic Fe site on the Cu surface,while metallic Cu is retained.Thus,UiO-66@Cu provides active sites of Cu for CO_(2)RR and leads to highly efficient and selective production of hydrocarbons.