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Author Huygh, S.; Bogaerts, A.; Bal, K.M.; Neyts, E.C.
Title High Coke Resistance of a TiO2Anatase (001) Catalyst Surface during Dry Reforming of Methane Type A1 Journal Article
Year 2018 Publication Journal Of Physical Chemistry C Abbreviated Journal J Phys Chem C
Volume 122 Issue 17 Pages 9389-9396
Keywords (up) A1 Journal Article; Plasma, laser ablation and surface modeling Antwerp (PLASMANT) ;
Abstract The resistance of a TiO2 anatase (001) surface to coke formation was studied in the context of dry reforming of methane using density functional theory (DFT) calculations. As carbon atoms act as precursors for coke formation, the resistance to coke formation can be measured by the carbon coverage of the surface. This is related to the stability of different CHx (x = 0−3) species and their rate of hydrogenation and dehydrogenation on the TiO2 surface. Therefore, we studied the reaction mechanisms and their corresponding rates as a function of the temperature for the dehydrogenation of the species on the surface. We found that the stabilities of C and CH are significantly lower than those of CH3 and CH2. The hydrogenation rates of the different species are significantly higher than the dehydrogenation rates in a temperature range of 300−1000 K. Furthermore, we found that dehydrogenation of CH3, CH2, and CH will only occur at appreciable rates starting from 600, 900, and 900 K, respectively. On the basis of these results, it is clear that the anatase (001) surface has a high coke resistance, and it is thus not likely that the surface will become poisoned by coke during dry reforming of methane. As the rate limiting step in dry reforming is the dissociative adsorption of CH4, we studied an alternative approach to thermal catalysis. We found that the temperature threshold for dry reforming is at least 700 K. This threshold temperature may be lowered by the use of plasma-catalysis, where the appreciable rates of adsorption of plasma-generated CHx radicals result in bypassing the rate limiting step of the reaction.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000431723700014 Publication Date 2018-05-03
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1932-7447 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.536 Times cited 1 Open Access OpenAccess
Notes Federaal Wetenschapsbeleid, IAP/7 ; Fonds Wetenschappelijk Onderzoek, G.0217.14N ; Onderzoeksfonds, Universiteit Antwerpen, 32249 ; Approved Most recent IF: 4.536
Call Number PLASMANT @ plasmant @c:irua:151529c:irua:152816 Serial 5000
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Author Vermeiren, V.; Bogaerts, A.
Title Supersonic Microwave Plasma: Potential and Limitations for Energy-Efficient CO2Conversion Type A1 Journal Article
Year 2018 Publication Journal Of Physical Chemistry C Abbreviated Journal J Phys Chem C
Volume 122 Issue 45 Pages 25869-25881
Keywords (up) A1 Journal Article; Plasma, laser ablation and surface modeling Antwerp (PLASMANT) ;
Abstract Supersonic flows provide a high thermodynamic

nonequilibrium, which is crucial for energy-efficient conversion of

CO 2 in microwave plasmas and are therefore of great interest.

However, the effect of the flow on the chemical reactions is poorly

understood. In this work, we present a combined flow and plasma

chemical kinetics model of a microwave CO 2 plasma in a Laval

nozzle setup. The effects of the flow field on the different dissociation

and recombination mechanisms, the vibrational distribution, and the

vibrational transfer mechanism are discussed. In addition, the effect

of experimental parameters, like position of power deposition, outlet

pressure, and specific energy input, on the CO 2 conversion and

energy efficiency is examined. The short residence time of the gas in

the plasma region, the shockwave, and the maximum critical heat,

and thus power, that can be added to the flow to avoid thermal

choking are the main obstacles to reaching high energy efficiencies.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000451101400016 Publication Date 2018-11-15
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1932-7447 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.536 Times cited 5 Open Access Not_Open_Access
Notes Fonds Wetenschappelijk Onderzoek, G.0383.16N ; Approved Most recent IF: 4.536
Call Number PLASMANT @ plasmant @c:irua:155412 Serial 5070
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