Sustainable conversion of carbon dioxide into diverse hydrocarbon fuels via molten salt electrolysis

Al-Juboori, O., Sher, F. ORCID: 0000-0003-2890-5912, Rahman, S., Rasheed, T. and Chen, G.Z., 2020. Sustainable conversion of carbon dioxide into diverse hydrocarbon fuels via molten salt electrolysis. ACS Sustainable Chemistry and Engineering, 8 (51), pp. 19178-19188. ISSN 2168-0485

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Abstract

In recent decades, the unlimited use of fossil fuels mostly for power generation has emitted a huge amount of carbon dioxide into the atmosphere which in return has led to global warming. Here we use green technology, the molten salt electrochemical system comprising titanium and mild steel as a cathode with a graphite anode, whereas molten carbonate (Li2CO3–Na2CO3–K2CO3; 43.5:31.5:25 mol %), hydroxide (LiOH–NaOH; 27:73 and KOH–NaOH; 50:50 mol %), and chlorides (KCl–LiCl; 41–59 mol %) salts as electrolytes This study investigates the effect of temperature, feed gas ratio CO2/H2O, and use of different cathode materials on hydrocarbon product along with current efficiencies. Gas chromatography and mass spectroscopy have been applied to analyze the gas products. According to GC results, more specific results in terms of high molecular weight and long chain hydrocarbons were obtained using titanium cathodic material rather than mild steel. The results revealed that among all the electrolytes, molten carbonates at 1.5 V and 425 °C produced higher hydrocarbons as C7H16 while all other produced CH4. The optimum conditions for hydrocarbon formation and higher current efficiencies in the case of molten carbonates were found to be 500 °C under a molar ratio of CO2/H2O of 15.6. However, the current efficiencies do not change on increasing the temperature from 425 to 500 °C and is maintained at 99% under a molar ratio of CO2/H2O of 15.6. The total current efficiency of the entire cathodic product reduced clearly from 95 to 79% by increasing the temperature under a CO2/H2O ratio of 9.2 due to the reduction of hydrocarbon generation in this case, despite the formation of C7H16. Therefore, due to its fast electrolytic conversion rate and low cost (no use of catalyst) the practice of molten salts could be an encouraging and promising technology for future investigation for hydrocarbon fuel formation.

Item Type: Journal article
Publication Title: ACS Sustainable Chemistry and Engineering
Creators: Al-Juboori, O., Sher, F., Rahman, S., Rasheed, T. and Chen, G.Z.
Publisher: American Chemical Society (ACS)
Date: 28 December 2020
Volume: 8
Number: 51
ISSN: 2168-0485
Identifiers:
NumberType
10.1021/acssuschemeng.0c08209DOI
1567838Other
Rights: This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS Sustainable Chemistry and Engineering, copyright © 2020 American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1021/acssuschemeng.0c08209
Divisions: Schools > School of Science and Technology
Record created by: Laura Ward
Date Added: 25 Jul 2022 14:31
Last Modified: 25 Jul 2022 14:33
URI: http://irep.ntu.ac.uk/id/eprint/46704

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