Editors: | F. Kongoli, R. Fehrmann, V. Papangelakis, I.Paspaliaris, G. Saevarsdottir. |
Publisher: | Flogen Star OUTREACH |
Publication Year: | 2022 |
Pages: | 100 pages |
ISBN: | 978-1-989820-40-7(CD) |
ISSN: | 2291-1227 (Metals and Materials Processing in a Clean Environment Series) |
The global warming, caused by the increase in the emission of greenhouse gases, such as carbon dioxide (CO2), methane (CH4) and others, has been recognized as a serious environmental problem of the humanity. At the present time, the annual increase in CO2 is 3200-3600 million tons. According to the calculations of the International Group of Experts on Climate Change (IGECC), if CO2 emissions continue to increase at this rate, the average annual temperature on the Earth will increase by 1.5-4.5 ºC by the end of the 21st century. Therefore, the effective utilization of carbon dioxide is a topical scientific and environmental problem. The CO2 utilization methods can be conditionally divided into biological, chemical and physical ones. Among the chemical methods, the electrochemical method is an efficient but still poorly developed method. It involves the electrochemical decomposition of CO2 at the cathode. Depending on the electrolysis conditions (electrolytic bath composition, temperature, current density, electrode materials), the chemical composition of cathodic products can change dramatically. The electroreduction of carbon dioxide in molten salts can be considered one of the possible ways of solving this problem. A peculiarity of the electroreduction of CO2 dissolved in molten salts is the deposition of a solid carbon phase on the cathode in contrast to aqueous, organic (ionic liquids) and solid-oxide electrolytes. The investigation of this process is dealt with in a large number of original papers and reviews [1-3]. These works contain certain contradictions as to the compositions of electrolysis products; there are also contradictions in the interpretation of obtained data and proposed mechanisms of electrode processes. The aim of this report is to consider the present state of research on the electrochemical conversion of carbon dioxide from different types of electrolytes: aqueous, organic (ionic liquids), solid-oxide and molten salt. The comparative analysis of the effectiveness of using these electrolytes, as well as cathodic products obtained by carbon dioxide decomposition and prospects for their use will be done. Special emphasis is made on the electrochemical decomposition of carbon dioxide in salt melts, several variants of decomposition are shown, the advantages and disadvantages of each variant are analyzed.
[1] D. Chery, V. Lair, and M. Cassir, Frontiers in Energy Research 3 (2015) 43. [2] I.A. Novoselova, S.V. Kuleshov, S.V. Volkov, and V.N. Bykov, Electrochimica Acta 211 (2016) 343-355. [3] R. Jiang, M. Gao, X.Mao, and D. Wang, Current Opinion in Electrochemistry 17 (2019) 38-46.