Redefining the Microwave Plasma-Mediated CO2 Reduction Efficiency Limit: The Role of O-CO2 Association

A. van de Steeg, P. Viegas, A. Silva, T. Butterworth, A. van Bavel, J. Smits, P. Diomede, M. van de Sanden, G. van Rooij*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

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Reduction of CO2 to CO for sustainable fuel production is studied in high-temperature (>3500 K) microwave plasma. Raman scattering and chemical kinetics modeling reveal chemistry rates with spatial resolution that explain previously reported peak energy efficiency values of 50%. The necessary product quenching is established by fast transport in the core, at frequencies of 10(5) s(-1), facilitating rapid mass and energy transfer between products and feedstock CO,. Moreover, the resulting chemical nonequilibrium yields additional CO2 dissociation in O-CO2 association, a reaction responsible for up to 45% of CO production. Three different thermal chemistry sets are invoked to qualitatively confirm this picture. It is shown how these lack predictive accuracy in the high gas temperature regime studied, which indicates that new CO2 chemistry rate coefficients are highly desirable. Improving reactor design with the identified enhancement mechanisms in mind can increase efficiency up to the newly defined thermal limit of 70%.
Original languageEnglish
Pages (from-to)2876-2881
Number of pages6
JournalACS Energy Letters
Issue number8
Publication statusPublished - 13 Aug 2021



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