Electrochemical Deposited Zeolitic Imidazolate Frameworks as an Efficient Electrocatalyst for CO2 Electrocatalytic Reduction

Abstract

AbstractElectrocatalytic reduction of CO2 over zeolitic imidazolate frameworks (ZIFs) generally has poor activity and low CO Faradaic efficiency due to the poor contact between conductive substrate and ZIFs synthesized by ex‐situ method. Here, ZIF‐8 films on Zn foils (ZIF‐8/Zn) fabricated by in‐situ electrochemical deposition were used for CO2 electroreduction in ionic liquid‐based ternary electrolyte. Tunable morphology and thickness of ZIF‐8 film can regulate the activity of CO2 electroreduction. The ZIF‐8/Zn‐40 electrode demonstrates the highest CO Faradaic efficiency (91.8 %) with the current density of 12.6 mA cm−2 at −1.9 V vs. Ag/Ag+, which is superior to the performance of ZIF‐8/CP electrode prepared by ex‐situ method. The excellent activity of ZIF‐8/Zn‐40 electrode is mainly attributed to abundant active sites in 3D structures with largest surface area, tight and good contact between ZIF‐8 film and Zn foil, faster rate CO2 diffusion, and synergistic effect between electrode and [Bmim]PF6‐containing electrolyte. The facile synthesis of ZIF‐8/Zn electrode provides a novel technology to design efficient electrodes for CO2 electroreduction.