Review on CO2 Management: From CO2 Sources, Capture, and Conversion to Future Perspectives of Gas-Phase Electrochemical Conversion and Utilization

Fossil organic chemicals are the main resources for both energy demands and industrial organic chemistry. Burning or decomposing of these materials releases carbon dioxide (CO2) and carbon monoxide (CO), causing global environmental changes. This issue is the main concern related to the current earth situation. It could be a critical task that excess CO2 be captured and converted into the original resources. In this overview, CO2 origin and withdrawing mechanism and the thermodynamics, kinetics, and pathway of the CO2 reduction reaction are summarized, and then the methods of CO2 reduction are briefly compared with respect to commercialization capability. Electrochemistry is known as a green and cost-effective technique, which motivates many chemical reactions in technological areas. Conversion of CO2 into the intrinsic chemicals assisted by electrochemistry is an imperative subject in terms of both energy demand and greenhouse gas control. However, some drawbacks such as less dissolution of CO2 gas in aqueous electrolytes and low selectivity of products decrease the efficiency of CO2 recycling by use of electrochemical procedures. Next, recent trends in development of electrocatalysts and various factors in electrochemical reduction are reviewed. After that, challenges in liquid-phase CO2 reduction and insights into gas-phase CO2 reduction assisted by electrochemical gas diffusion electrode (GDE) are summarized. Taking into account techno-economic analysis, the future of GDE in electrochemical CO2 conversion and the development of new advanced procedures toward improving selectivity and stability with high faradaic efficiency are discussed. Finally, a brief discussion about Li/CO2 batteries and H2/CO2 fuel cells combined with CO2/H2O electrolysis cells as a future of CO2 management and utilization are presented.