Recent progress in electrochemical reduction of CO2 into formate and C2 compounds

Global warming and climate change enhanced by the high atmospheric CO2 concentration have been correlated to the frequency of extreme weather causing a significant amount of property damage and loss of human lives. Among current atmospheric CO2 concentration control strategies, the electrochemical reduction of CO2 (eCO2R) process is a promising technology that can utilize CO2 gas as a feedstock to produce valuable C1 and C2 compounds at room temperature. Since the eCO2R reaction is limited by high activation energy and mass transfer, the choice of the electrocatalyst and the configuration of the CO2 electrolyzer have a significant impact on the activity and selectivity of the eCO2R process. This review discusses current technological advancements of electrocatalytic materials and the design of the gas diffusion electrodes that increase energy efficiency and reduce the mass transfer resistance of the CO2 conversion into C1 with a focus on formate and C2 chemical compounds. A techno-economic analysis is briefly provided, and future and technical challenges of the CO2 conversion at the industrial scale into formate and C2 products are also addressed.