Highly efficient electrochemical reduction of CO₂ to CH₄ in an ionic liquid using a metal–organic framework cathode

Abstract

Highly efficient electrochemical reduction of CO₂ to CH₄ is of great importance, but is challenging. Herein, Zn-1,3,5-benzenetricarboxylic acid metal-organic frameworks (Zn-BTC MOFs) deposited on carbon paper (CP) were used as cathodes in electrochemical reduction of CO₂ using ionic liquids (ILs) as the electrolytes, which was the first work on combination of a MOF electrode and an pure IL electrolyte in the electrochemical reduction of CO₂. It was found that the efficiency of the reaction depended strongly on the morphology of the Zn-MOFs. Compared with the commonly used metal electrodes, the electrochemical reaction showed much higher selectivity to CH₄ and current density, and the overpotentials for CH₄ is much lower. The excellent combination of the MOF cathodes and ILs opens a way for reduction of CO₂ to CH₄ effectively.