Current achievements and the future direction of electrochemical CO₂ reduction: A short review

Abstract

Electrochemical CO₂ reduction (CO2RR) has received much attention for its ability to generate value-added chemicals from a molecule that would otherwise be a waste end-product. Numerous studies have emerged in the past decades, but the renewable and sustainable carbon-neutral CO₂ reduction process is yet to be industrialized. Here, we review the progress and bottlenecks of the electrochemical CO₂ reduction technologies over the past 15 years (2004–2018) to examine whether CO2RR process is to be applicable in a large-scale. Although the techno-economic analysis and pilot plants based on liquid-phase electrolysis have shown some positive results, current densities of the liquid-phase electrochemical CO₂ reduction are well below what techno-economic analyzes have projected due to its intrinsic limitations of solubility. On the other hand, the gas-phase electrolysis of CO₂ has shown superior performance parameters compared to the liquid-phase electrolysis, especially in the current densities, showing commercial viability although its techno-economic analysis is yet to be performed. Herein, we offer some perspectives and guidelines where future research in CO₂ electrolysis should aim. Based on the performance parameters obtained from the lab-scale gas-phase reactions, we believe that the current negative outlooks towards the industrial feasibility of the CO₂ electrolysis system could turn to positive views.

Keywords:

• CO₂ electrolysis
• liquid-phase electrolysis
• gas-phase electrolysis

Acknowledgment

This work has been supported by ‘‘Next Generation Carbon Upcycling Project’’ (Project No. 2017M1A2A2043150 and No. 2017M1A2A2043122) through the National Research Foundation (NRF) funded by the Ministry of Science and ICT, Republic of Korea.