Received: 19 May 2016 | Revised: 26 August 2016 | Accepted: 26 August 2016 DOI 10.1002/ppap.201600070 FEATURE ARTICLE Plasma based CO 2 and CH 4 conversion: A modeling perspective Annemie Bogaerts 1 * | Christophe De Bie 1 | Ramses Snoeckx 1 | Tomas Kozák 1,2 1 Research Group PLASMANT, Department of Chemistry, University of Antwerp, Wilrijk-Antwerp, Belgium 2 Department of Physics and NTIS-European Centre of Excellence, University of West Bohemia, Plzen, Czech Republic *Correspondence Annemie Bogaerts, Research Group PLASMANT, Department of Chemistry, University of Antwerp, Universiteitsplein 1, Wilrijk-Antwerp B-2610, Belgium. Email: annemie.bogaerts@uantwerpen.be Funding information Inter-university Attraction Pole (IAP/7), Belgian Federal Office for Science Policy (BELSPO), Francqui Research Foundation, Fund for Scientific Research Flanders, Grant number G.0383.16N; Hercules Foundation, Flemish Government, UAntwerpen This paper gives an overview of our plasma chemistry modeling for CO 2 and CH 4 conversion in a dielectric barrier discharge (DBD) and microwave (MW) plasma. We focus on pure CO 2 splitting and pure CH 4 reforming, as well as mixtures of CO 2 /CH 4 , CH 4 /O 2 , and CO 2 /H 2 O. We show calculation results for the conversion, energy efficiency, and product formation, in comparison with experiments where possible. We also present the underlying chemical reaction pathways, to explain the ob- served trends. For pure CO 2 , a comparison is made between a DBD and MW plasma, illustrating that the higher energy efficiency of the latter is attributed to the more important role of the vibra- tional levels. KEYWORDS 0D chemical kinetics model, CO 2 and CH 4 conversion, dielectric barrier discharges, microwave plasmas, plasma chemistry modeling 1 | INTRODUCTION In recent years, there is increasing interest in plasma used for CO 2 and CH 4 conversion. Several types of plasma reactors are being investigated for this purpose, including (packed bed) dielectric barrier discharges (DBDs), [1–14] microwave (MW) plasmas, [15–20] ns-pulsed, [21] spark, [22–24] and gliding arc (GA) [25–32] discharges. Research focuses on pure CO 2 splitting into CO and O 2 , on CH 4 (and other hydrocarbons) reforming, and on mixtures of CO 2 with a hydrogen-source, that is, mainly CH 4 , but sometimes also H 2 O or H 2 , to produce value-added chemicals like syngas, hydrocarbons, and oxygenated products. Key performance indicators are the conversion and the energy efficiency of the process, as well as the possibility to produce specific value-added chemicals with good yields and selectivity. To realize the latter, the plasma should be combined with a catalyst (e.g., [3–9,33,34] ), as the plasma itself is a too reactive environment, and thus produces a wealth of reactive species, which easily recombine to form new molecules, without any selectivity. To improve the conversion, product yields and energy efficiency of this process, a good insight in the underlying plasma chemistry is crucial. This can be obtained by experiments, but measuring the reactive species densities inside the plasma is far from evident. Therefore, modeling of the plasma chemistry can be a valuable alternative, as it provides information on the most important chemical reaction pathways, and how to tune them to improve the conversion, energy efficiency, and product formation. In the 80s and 90s, some papers have been published on CO 2 plasma chemistry modeling, with applications to CO 2 lasers. [35–37] These models, however, did not consider the vibrational kinetics, which are important for energy efficient CO 2 conversion. [38] Some other papers have described the vibrational kinetics for gas flow applications, [39,40] but without focusing on the plasma chemistry. In 1981 Rusanov Plasma Process. Polym. 2016; 9999: 1–21 © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim | 1 www.plasma-polymers.com Early View Publication; these are NOT the final page numbers, use DOI for citation !! R