Electrochemical Reduction of CO2 in Atmospheric Level Using Bimetallic Catalysts on Liquid-Electrolyte Free Cathodic Half Cell

Abstract

The climate crisis, caused by anthropogenic greenhouse gas (GHG), is one of the most urgent environmental issues. CO2 is one of the GHGs that contributes the most to global warming. Electrochemical CO2 reduction is considered one of the most promising technologies to solve the global warming problem and realize resource recovery. CO2 reduction technology is practically limited because most CO2 reduction techniques are theoretically based on gas-liquid or gas-liquid-solid reactions. Conventional electrochemical CO2 reduction has applied liquid electrolytes, which have the limitation of mass transfer and the problem of liquid product separation. Up to now, most studies have focused on applying high-level CO2 (pure CO2 and % level), which is also practically limited to field application.This study aimed to establish the gas-solid reaction to enable the electrochemical reduction of CO2 at the atmospheric level (hundreds ppm level). We proposed agar gel solid electrolyte inserted between the bimetallic catalysts and ion exchange membranes system for the gas phase CO2 reduction at liquid electrolyte free state. A bimetallic (Cu-Ni or Cu-Zn) metal-organic frameworks (MOFs) used, as electrocatalyst, after coating on 3D foam base. The electrode surface characteristics were confirmed through x-ray diffraction (XRD) and scanning electron microscope (SEM) analysis, and the presence of bimetals on the electrode was confirmed through energy dispersive X-ray spectrometer (EDS). The redox behaviors of the electrode and it’s catalytic CO2 reaction were confirmed through gas-phase cyclic voltammetry and linear sweep voltammetry. It was observed in the experiment that CO2 removal reached up to 99%, and initial product analysis ended with methane, methanol, and dimethyl ether, which will be analyzed and discussed.AcknowledgmentThis research was supported by Basic Science Research Program through the National Research Foundation of Korea(NRF) funded by the Ministry of Education(NRF-2021R1I1A1A01049901)