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Author Berthelot, A.; Bogaerts, A.
Title Modeling of CO2Splitting in a Microwave Plasma: How to Improve the Conversion and Energy Efficiency Type A1 Journal article
Year 2017 Publication The journal of physical chemistry: C : nanomaterials and interfaces Abbreviated Journal J Phys Chem C
Volume 121 Issue 121 Pages 8236-8251
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Microwave plasmas are one of the most promising techniques for CO2 conversion into value-added chemicals and fuels since they are very energy efficient. Nevertheless, experiments show that this high energy efficiency is only reached at low pressures and significantly drops toward atmospheric pressure, which is a clear limitation for industrial applications. In this paper, we use a zerodimensional reaction kinetics model to simulate a CO2 microwave plasma in a pressure range from 50 mbar to 1 bar, in order to evaluate the reasons for this decrease in energy efficiency at atmospheric pressure. The code includes a detailed description of the vibrational kinetics of CO2, CO, and O2 as well as the energy exchanges between them because the vibrational kinetics is known to be crucial for energy efficient CO2 splitting. First, we use a self-consistent gas temperature calculation in order to assess the key performance indicators for CO2 splitting, i.e., the CO2 conversion and corresponding energy efficiency. Our results indicate that lower pressures and higher power densities lead to more vibrational excitation, which is beneficial for the conversion. We also demonstrate the key role of the gas temperature. The model predicts the highest conversion and energy efficiencies at pressures around 300 mbar, which is in agreement with experiments from the literature. We also show the beneficial aspect of fast gas cooling in the afterglow at high pressure. In a second step, we study in more detail the effects of pressure, gas temperature, and power density on the vibrational distribution function and on the dissociation and recombination mechanisms of CO2, which define the CO2 splitting efficiency. This study allows us to identify the limiting factors of CO2 conversion and to propose potential solutions to improve the process.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000400039300002 Publication Date 2017-04-20
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 1932-7447 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.536 Times cited 47 Open Access OpenAccess
Notes Federaal Wetenschapsbeleid; Approved Most recent IF: 4.536
Call Number PLASMANT @ plasmant @ c:irua:142809 Serial 4567
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Author Trenchev, G.; Kolev, S.; Wang, W.; Ramakers, M.; Bogaerts, A.
Title CO2Conversion in a Gliding Arc Plasmatron: Multidimensional Modeling for Improved Efficiency Type A1 Journal article
Year 2017 Publication The journal of physical chemistry: C : nanomaterials and interfaces Abbreviated Journal J Phys Chem C
Volume 121 Issue 44 Pages 24470-24479
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract The gliding arc plasmatron (GAP) is a highly efficient atmospheric plasma source, which is very promising for CO2 conversion applications. To understand its operation principles and to improve its application, we present here comprehensive modeling results, obtained by means of computational fluid dynamics simulations and plasma modeling. Because of the complexity of the CO2 plasma, a full 3D plasma model would be computationally impractical. Therefore, we combine a 3D turbulent gas flow model with a 2D plasma and gas heating model in order to calculate the plasma parameters and CO2 conversion characteristics. In addition, a complete 3D gas flow and plasma model with simplified argon chemistry is used to evaluate the gliding arc evolution in space and time. The calculated values are compared with experimental data from literature as much as possible in order to validate the model. The insights obtained in this study are very helpful for improving the application of CO2 conversion, as they allow us to identify the limiting factors in the performance, based on which solutions can be provided on how to further improve the capabilities of CO2 conversion in the GAP.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000415140400014 Publication Date 2017-11-09
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 1932-7447 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.536 Times cited Open Access OpenAccess
Notes H2020 Marie Sklodowska-Curie Actions, 657304 ; Fonds Wetenschappelijk Onderzoek, 11U5316N G038316N ; Approved Most recent IF: 4.536
Call Number PLASMANT @ plasmant @c:irua:147193 Serial 4765
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Author Heijkers, S.; Bogaerts, A.
Title CO2Conversion in a Gliding Arc Plasmatron: Elucidating the Chemistry through Kinetic Modeling Type A1 Journal article
Year 2017 Publication The journal of physical chemistry: C : nanomaterials and interfaces Abbreviated Journal J Phys Chem C
Volume 121 Issue 41 Pages 22644-22655
Keywords A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract By means of chemical kinetics modeling, it is possible to elucidate the main dissociation mechanisms of CO2 in a gliding arc plasmatron (GAP). We obtain good agreement between the calculated and experimental conversions and energy efficiencies, indicating that the model can indeed be used to study the underlying mechanisms. The calculations predict that vibration-induced dissociation is the main dissociation mechanism of CO2, but it occurs mainly from the lowest vibrational levels because of fast thermalization of the vibrational distribution. Based on these findings, we propose ideas for improving the performance of the GAP, but testing of these ideas in the simulations reveals that they do not always lead to significant enhancement, because of other side effects, thus illustrating the complexity of the process. Nevertheless, the model allows more insight into the underlying mechanisms to be obtained and limitations to be identified.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000413617900007 Publication Date 2017-10-19
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 1932-7447 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.536 Times cited 6 Open Access OpenAccess
Notes Federaal Wetenschapsbeleid, IAP/7 ; Fonds Wetenschappelijk Onderzoek, G.0383.16N ; Approved Most recent IF: 4.536
Call Number PLASMANT @ plasmant @c:irua:147436 Serial 4801
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Author Wang, W.; Snoeckx, R.; Zhang, X.; Cha, M.S.; Bogaerts, A.
Title Modeling Plasma-based CO2and CH4Conversion in Mixtures with N2, O2, and H2O: The Bigger Plasma Chemistry Picture Type A1 Journal article
Year 2018 Publication The journal of physical chemistry: C : nanomaterials and interfaces Abbreviated Journal J Phys Chem C
Volume 122 Issue 16 Pages 8704-8723
Keywords A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Because of the unique properties of plasma technology, its use in gas conversion applications is gaining significant interest around the globe. Plasma-based CO2 and CH4 conversion has become a major research area. Many investigations have already been performed regarding the single-component gases, that is, CO2 splitting and CH4 reforming, as well as for two-component mixtures, that is, dry reforming of methane

(CO2/CH4), partial oxidation of methane (CH4/O2), artificial photosynthesis (CO2/H2O), CO2 hydrogenation (CO2/H2), and even first steps toward the influence of N2 impurities have been taken, that is, CO2/N2 and CH4/N2. In this Feature Article we briefly discuss the advances made in literature for these different steps from a plasma chemistry modeling point of view. Subsequently, we present a comprehensive plasma chemistry set, combining the knowledge gathered in this field so far and supported with extensive experimental data. This set can be used for chemical kinetics plasma modeling for all possible combinations of CO2, CH4, N2, O2, and H2O to investigate the bigger picture of the underlying plasmachemical pathways for these mixtures in a dielectric barrier discharge plasma. This is extremely valuable

for the optimization of existing plasma-based CO2 conversion and CH4 reforming processes as well as for investigating the influence of N2, O2, and H2O on these processes and even to support plasma-based multireforming processes.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000431151200002 Publication Date 2018-04-26
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 1932-7447 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.536 Times cited 28 Open Access OpenAccess
Notes Federaal Wetenschapsbeleid, IAP/7 ; King Abdullah University of Science and Technology; H2020 Marie Sklodowska-Curie Actions, 657304 ; Fonds Wetenschappelijk Onderzoek, G.0217.14N G.0383.16N G.0254.14N ; Approved Most recent IF: 4.536
Call Number PLASMANT @ plasmant @c:irua:150969 Serial 4922
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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 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 (up) 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 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 (up) 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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Author Heijkers, S.; Martini, L.M.; Dilecce, G.; Tosi, P.; Bogaerts, A.
Title Nanosecond Pulsed Discharge for CO2Conversion: Kinetic Modeling To Elucidate the Chemistry and Improve the Performance Type A1 Journal article
Year 2019 Publication The journal of physical chemistry: C : nanomaterials and interfaces Abbreviated Journal J Phys Chem C
Volume 123 Issue 19 Pages 12104-12116
Keywords A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract We study the mechanisms of CO2 conversion in a nanosecond repetitively pulsed (NRP) discharge, by means of a chemical kinetics model. The calculated conversions and energy efficiencies are in reasonable agreement with experimental results over a wide range of specific energy input values, and the same applies to the evolution of gas temperature and CO2 conversion as a function of time in the afterglow, indicating that our model provides a realistic picture of the underlying mechanisms in the NRP discharge and can be used to identify its limitations and thus to suggest further improvements. Our model predicts that vibrational excitation is very important in the NRP discharge, explaining why this type of plasma yields energy-efficient CO2 conversion. A significant part of the CO2 dissociation occurs by electronic excitation from the lower vibrational levels toward repulsive electronic states, thus resulting in dissociation. However, vibration−translation (VT) relaxation (depopulating the higher vibrational levels) and CO + O recombination (CO + O + M → CO2 + M), as well as mixing of the converted gas with fresh gas entering the plasma in between the pulses, are limiting factors for the conversion and energy efficiency. Our model predicts that extra cooling, slowing down the rate of VT relaxation and of the above recombination reaction, thus enhancing the contribution of the highest vibrational levels to the overall CO2 dissociation, can further improve the performance of the NRP discharge for energy-efficient CO2 conversion.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000468368800009 Publication Date 2019-05-16
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 1932-7447 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.536 Times cited 4 Open Access Not_Open_Access: Available from 26.04.2020
Notes Fonds Wetenschappelijk Onderzoek, G.0383.16N ; The authors acknowledge financial support from the Fund for Scientific Research, Flanders (FWO; Grant no. G.0383.16N). Approved Most recent IF: 4.536
Call Number PLASMANT @ plasmant @UA @ admin @ c:irua:159976 Serial 5174
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Author Vermeiren, V.; Bogaerts, A.
Title Improving the Energy Efficiency of CO2Conversion in Nonequilibrium Plasmas through Pulsing Type A1 Journal article
Year 2019 Publication The journal of physical chemistry: C : nanomaterials and interfaces Abbreviated Journal J Phys Chem C
Volume 123 Issue 29 Pages 17650-17665
Keywords A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Nonequilibrium plasmas offer a pathway for energy-efficient CO2 conversion through vibrationally induced dissociation. However, the efficiency of this pathway is limited by a rise in gas temperature, which increases vibrational−translational (VT) relaxation and quenches the vibrational levels. Therefore, we investigate here the effect of plasma pulsing on the VT nonequilibrium and on the CO2 conversion by means of a zerodimensional chemical kinetics model, with self-consistent gas temperature calculation. Specifically, we show that higher energy efficiencies can be reached by correctly tuning the plasma pulse and interpulse times. The ideal plasma pulse time corresponds to the time needed to reach the highest vibrational temperature. In addition, the highest energy efficiencies are obtained with long interpulse times, that is, ≥0.1 s, in which the gas temperature can entirely drop to room temperature. Furthermore, additional cooling of the reactor walls can give higher energy efficiencies at shorter interpulse times of 1 ms. Finally, our model shows that plasma pulsing can significantly improve the energy efficiency at low reduced electric fields (50 and 100 Td, typical for microwave and gliding arc plasmas) and intermediate ionization degrees (5 × 10−7 and 10−6).
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000477785000003 Publication Date 2019-07-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 1932-7447 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.536 Times cited 1 Open Access
Notes Fonds Wetenschappelijk Onderzoek, G.0383.16N ; This research was supported by the FWO project (grant G.0383.16N). The calculations were performed using the Turing HPC infrastructure at the CalcUA core facility of the Universiteit Antwerpen (UAntwerpen), a division of the Flemish Supercomputer Center VSC, funded by the Hercules Foundation, the Flemish Government (department EWI), and the UAntwerpen. We also like to thank N. Britun (ChIPS) for the interesting discussions. Approved Most recent IF: 4.536
Call Number PLASMANT @ plasmant @c:irua:161621 Serial 5289
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Author Van Alphen, S.; Vermeiren, V.; Butterworth, T.; van den Bekerom, D.C.M.; van Rooij, G.J.; Bogaerts, A.
Title Power Pulsing To Maximize Vibrational Excitation Efficiency in N2Microwave Plasma: A Combined Experimental and Computational Study Type A1 Journal article
Year 2020 Publication Journal Of Physical Chemistry C Abbreviated Journal J Phys Chem C
Volume 124 Issue 3 Pages 1765-1779
Keywords A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Plasma is gaining increasing interest for N2 fixation, being a flexible, electricity-driven alternative for the current conventional fossil fuel-based N2 fixation processes. As the vibrational-induced dissociation of N2 is found to be an energy-efficient pathway to acquire atomic N for the fixation processes, plasmas that are in vibrational nonequilibrium seem promising for this application. However, an important challenge in using nonequilibrium plasmas lies in preventing vibrational−translational (VT) relaxation processes, in which vibrational energy crucial for N2 dissociation is lost to gas heating. We present here both experimental and modeling results for the vibrational and gas temperature in a microsecond-pulsed microwave (MW) N2 plasma, showing how power pulsing can suppress this unfavorable VT relaxation and achieve a maximal vibrational nonequilibrium. By means of our kinetic model, we demonstrate that pulsed plasmas take advantage of the long time scale on which VT processes occur, yielding a very pronounced nonequilibrium over the whole N2 vibrational ladder. Additionally, the effect of pulse parameters like the pulse frequency and pulse width are investigated, demonstrating that the advantage of pulsing to inhibit VT relaxation diminishes for high pulse frequencies (around 7000 kHz) and long power pulses (above 400 μs). Nevertheless, all regimes studied here demonstrate a clear vibrational nonequilibrium while only requiring a limited power-on time, and thus, we may conclude that a pulsed plasma seems very interesting for energyefficient vibrational excitation.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000509438600001 Publication Date 2020-01-23
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 1932-7447 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.7 Times cited Open Access
Notes Fonds Wetenschappelijk Onderzoek, 30505023 GoF9618n ; This research was supported by the Excellence of Science FWO-FNRS project (FWO Grant ID GoF9618n, EOS ID 30505023). The calculations were performed using the Turing HPC infrastructure at the CalcUA core facility of the Universiteit Antwerpen (UAntwerpen), a division of the Flemish Supercomputer Center VSC, funded by the Hercules Foundation, the Flemish Government (department EWI) and the UAntwerpen. Approved Most recent IF: 3.7; 2020 IF: 4.536
Call Number PLASMANT @ plasmant @c:irua:165586 Serial 5443
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Author Heijkers, S.; Aghaei, M.; Bogaerts, A.
Title Plasma-Based CH4Conversion into Higher Hydrocarbons and H2: Modeling to Reveal the Reaction Mechanisms of Different Plasma Sources Type A1 Journal article
Year 2020 Publication Journal Of Physical Chemistry C Abbreviated Journal J Phys Chem C
Volume 124 Issue 13 Pages 7016-7030
Keywords A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Plasma is gaining interest for CH4 conversion into higher hydrocarbons and H2. However, the performance in terms of conversion and selectivity toward different hydrocarbons is different for different plasma types, and the underlying mechanisms are not yet fully understood. Therefore, we study here these mechanisms in different plasma sources, by means of a chemical kinetics model. The model is first validated by comparing the calculated conversions and hydrocarbon/H2 selectivities with experimental results in these different plasma types and over a wide range of specific energy input (SEI) values. Our model predicts that vibrational−translational nonequilibrium is negligible in all CH4 plasmas investigated, and instead, thermal conversion is important. Higher gas temperatures also lead to a more selective production of unsaturated hydrocarbons (mainly C2H2) due to neutral dissociation of CH4 and subsequent dehydrogenation processes, while three-body recombination reactions into saturated hydrocarbons (mainly C2H6, but also higher hydrocarbons) are dominant in low temperature plasmas.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000526328500007 Publication Date 2020-04-02
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 1932-7447 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.7 Times cited Open Access OpenAccess
Notes Universiteit Antwerpen; Vlaamse regering; Fonds Wetenschappelijk Onderzoek, G.0383.16N ; H2020 European Research Council, 810182 ; We acknowledge financial support from the Fund for Scientific Research, Flanders (FWO; Grant No. G.0383.16N), the Methusalem Grant, and the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (Grant Agreement No. 810182 − SCOPE ERC Synergy project). This work was carried out in part using the Turing HPC infrastructure at the CalcUA core facility of the Universiteit Antwerpen, a division of the Flemish Supercomputer Center VSC, funded by the Hercules Foundation, the Flemish Government (department EWI) and the University of Antwerp. Approved Most recent IF: 3.7; 2020 IF: 4.536
Call Number PLASMANT @ plasmant @c:irua:168096 Serial 6358
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Author Jafarzadeh, A.; Bal, K.M.; Bogaerts, A.; Neyts, E.C.
Title Activation of CO2on Copper Surfaces: The Synergy between Electric Field, Surface Morphology, and Excess Electrons Type A1 Journal article
Year 2020 Publication Journal Of Physical Chemistry C Abbreviated Journal J Phys Chem C
Volume 124 Issue 12 Pages 6747-6755
Keywords A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract In this work, we use density functional theory calculations to study the combined effect of external electric fields, surface morphology, and surface charge on CO2 activation over Cu(111), Cu(211), Cu(110), and Cu(001) surfaces. We observe that the binding energy of the CO2 molecule on Cu surfaces increases significantly upon increasing the applied electric field strength. In addition, rougher surfaces respond more effectively to the presence of the external electric field toward facilitating the formation of a carbonate-like CO2 structure and the transformation of the most stable adsorption mode from physisorption to chemisorption. The presence of surface charges further strengthens the electric field effect and consequently causes an improved bending of the CO2 molecule and C−O bond length elongation. On the other hand, a net charge in the absence of an externally applied electric field shows only a marginal effect on CO2 binding. The chemisorbed CO2 is more stable and further activated when the effects of an external electric field, rough surface, and surface charge are combined. These results can help to elucidate the underlying factors that control CO2 activation in heterogeneous and plasma catalysis, as well as in electrochemical processes.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000526396900030 Publication Date 2020-03-26
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 1932-7447 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.7 Times cited Open Access
Notes Bijzonder Onderzoeksfonds, 32249 ; The financial support from the TOP research project of the Research Fund of the University of Antwerp (grant ID: 32249) is highly acknowledged by the authors. The computational resources used in this study were provided by the VSC (Flemish Supercomputer Center), funded by the FWO and the Flemish Governmentdepartment EWI. Approved Most recent IF: 3.7; 2020 IF: 4.536
Call Number PLASMANT @ plasmant @c:irua:168606 Serial 6361
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Author Vermeiren, V.; Bogaerts, A.
Title Plasma-Based CO2Conversion: To Quench or Not to Quench? Type A1 Journal article
Year 2020 Publication Journal Of Physical Chemistry C Abbreviated Journal J Phys Chem C
Volume 124 Issue 34 Pages 18401-18415
Keywords A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Plasma technology is gaining increasing interest for CO2 conversion. The gas temperature in (and after) the plasma reactor largely affects the performance. Therefore, we examine the effect of cooling/quenching, during and after the plasma, on the CO2 conversion and energy efficiency, for typical “warm” plasmas, by means of chemical kinetics modeling. For plasmas at low specific energy input (SEI ∼ 0.5 eV/molecule), it is best to quench at the plasma end, while for high-SEI plasmas (SEI ∼ 4 eV/molecule), quenching at maximum conversion is better. For low-SEI plasmas, quenching can even increase the conversion beyond the dissociation in the plasma, known as superideal quenching. To better understand the effects of quenching at different plasma conditions, we study the dissociation and recombination rates, as well as the vibrational distribution functions (VDFs) of CO2, CO, and O2. When a high vibrational−translational (VT) nonequilibrium exists at the moment of quenching, the dissociation and recombination reaction rates both increase. Depending on the conversion degree at the moment of quenching, this can lead to a net increase or decrease of CO2 conversion. In general, however, and certainly for equilibrium plasmas at high temperature, quenching after the plasma helps prevent recombination reactions and clearly enhances the final CO2 conversion. We also investigate the effect of different quenching cooling rates on the CO2 conversion and energy efficiency. Finally, we compare plasma-based conversion to purely thermal conversion. For warm plasmas with typical temperatures of 3000−4000 K, the conversion is roughly thermal.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000566481000003 Publication Date 2020-08-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 1932-7447 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.7 Times cited Open Access OpenAccess
Notes Fonds Wetenschappelijk Onderzoek, G.0383.16N ; H2020 European Research Council, 810182 ; This research was supported by the FWO project (grant no. G.0383.16N) and the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (grant agreement no. 810182SCOPE ERC Synergy project). The calculations were performed using the Turing HPC infrastructure at the CalcUA core facility of the Universiteit Antwerpen (UAntwerpen), a division of the Flemish Supercomputer Center VSC, funded by the Hercules Foundation, the Flemish Government (department EWI), and the UAntwerpen. Approved Most recent IF: 3.7; 2020 IF: 4.536
Call Number PLASMANT @ plasmant @c:irua:172052 Serial 6407
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Author van ‘t Veer, K.; Engelmann, Y.; Reniers, F.; Bogaerts, A.
Title Plasma-Catalytic Ammonia Synthesis in a DBD Plasma: Role of Microdischarges and Their Afterglows Type A1 Journal article
Year 2020 Publication Journal Of Physical Chemistry C Abbreviated Journal J Phys Chem C
Volume 124 Issue 42 Pages 22871-22883
Keywords A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT); Movement Antwerp (MOVANT)
Abstract Plasma-catalytic ammonia synthesis is receiving ever increasing attention, especially in packed bed dielectric barrier discharge (DBD) reactors. The latter typically operate in the filamentary regime when used for gas conversion applications. While DBDs are in principle well understood and already applied in the industry, the incorporation of packing materials and catalytic surfaces considerably adds to the complexity of the plasma physics and chemistry governing the ammonia formation. We employ a plasma kinetics model to gain insights into the ammonia formation mechanisms, paying special attention to the role of filamentary microdischarges and their afterglows. During the microdischarges, the synthesized ammonia is actually decomposed, but the radicals created upon electron impact dissociation of N2 and H2 and the subsequent catalytic reactions cause a net ammonia gain in the afterglows of the microdischarges. Under our plasma conditions, electron impact dissociation of N2 in the gas phase followed by the adsorption of N atoms is identified as a rate-limiting step, instead of dissociative adsorption of N2 on the catalyst surface. Both elementary Eley−Rideal and Langmuir−Hinshelwood reaction steps can be found important in plasma-catalytic NH3 synthesis.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000585970300002 Publication Date 2020-10-22
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 1932-7447 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.7 Times cited Open Access OpenAccess
Notes Fonds Wetenschappelijk Onderzoek, 30505023 GoF9618n ; Fonds De La Recherche Scientifique – FNRS, 30505023 GoF9618n ; H2020 European Research Council, 810182 ;This research was supported by the Excellence of Science FWOFNRS project (FWO grant ID GoF9618n, EOS ID 30505023) and by the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement no 810182-SCOPE ERC Synergy project). The calculations were performed using the Turing HPC infrastructure at the CalcUA core facility of the Universiteit Antwerpen (UAntwerpen), a division of the Flemish Supercomputer Center VSC, funded by the Hercules Foundation, the Flemish Government (department EWI) and the UAntwerpen. The authors would also like to thank Järi Van den Hoek and Dr. Yury Gorbanev for providing the experimentally measured electrical characteristics and Dr. Fatme Jardali for creating the TOC graphics. Approved Most recent IF: 3.7; 2020 IF: 4.536
Call Number PLASMANT @ plasmant @c:irua:173587 Serial 6428
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Author Michiels, R.; Engelmann, Y.; Bogaerts, A.
Title Plasma Catalysis for CO2Hydrogenation: Unlocking New Pathways toward CH3OH Type A1 Journal article
Year 2020 Publication Journal Of Physical Chemistry C Abbreviated Journal J Phys Chem C
Volume 124 Issue 47 Pages 25859-25872
Keywords A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT); Movement Antwerp (MOVANT)
Abstract We developed a microkinetic model to reveal the effects of plasma-generated radicals, intermediates, and vibrationally excited species on the catalytic hydrogenation of CO2 to CH3OH on a Cu(111) surface. As a benchmark, we first present the mechanisms of thermal catalytic CH3OH formation. Our model predicts that the reverse water-gas shift reaction followed by CO hydrogenation, together with the formate path, mainly contribute to CH3OH formation in thermal catalysis. Adding plasma-generated radicals and intermediates results in a higher CH3OH turnover frequency (TOF) by six to seven orders of magnitude, showing the potential of plasma-catalytic CO2 hydrogenation into CH3OH, in accordance with the literature. In addition, CO2 vibrational excitation further increases the CH3OH TOF, but the effect is limited due to relatively low vibrational temperatures under typical plasma catalysis conditions. The predicted increase in CH3OH formation by plasma catalysis is mainly attributed to the increased importance of the formate path. In addition, the conversion of plasma-generated CO to HCO* and subsequent HCOO* or H2CO* formation contribute to CH3OH formation. Both pathways bypass the HCOO* formation from CO2, which is the main bottleneck in the process. Hence, our model points toward the important role of CO, but also O, OH, and H radicals, as they influence the reactions that consume CO2 and CO. In addition, our model reveals that the H pressure should not be smaller than ca. half of the O pressure in the plasma as this would cause O* poisoning, which would result in very small product TOFs. Thus, plasma conditions should be targeted with a high CO and H content as this is favorable for CH3OH formation, while the O content should be minimized.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000595545800023 Publication Date 2020-11-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 1932-7447 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.7 Times cited Open Access Not_Open_Access: Available from 15.07.2021
Notes Universiteit Antwerpen; Fonds Wetenschappelijk Onderzoek, 1114921N ; H2020 European Research Council, 810182 ; We acknowledge the financial support from the Fund for Scientific Research (FWO-Vlaanderen; grant ID 1114921N) and from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement no. 810182 − SCOPE ERC Synergy project) as well as from the DOC-PRO3 and the TOPBOF projects of the University of Antwerp. Approved Most recent IF: 3.7; 2020 IF: 4.536
Call Number PLASMANT @ plasmant @c:irua:173864 Serial 6443
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Author Loenders, B.; Engelmann, Y.; Bogaerts, A.
Title Plasma-Catalytic Partial Oxidation of Methane on Pt(111): A Microkinetic Study on the Role of Different Plasma Species Type A1 Journal article
Year 2021 Publication Journal Of Physical Chemistry C Abbreviated Journal J Phys Chem C
Volume 125 Issue 5 Pages 2966-2983
Keywords A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT); Movement Antwerp (MOVANT)
Abstract We use microkinetic modeling to examine the potential of plasma-catalytic partial oxidation (POX) of CH4 as a promising new approach to produce oxygenates. We study how different plasma species affect POX of CH4 on the Pt(111) surface, and we discuss the associated kinetic and mechanistic changes. We discuss the effect of vibrationally excited CH4 and O2, as well as plasma-generated radicals and stable intermediates. Our results show that vibrational excitation enhances the turnover frequency (TOF) of catalytic CH4 dissociation and has good potential for improving the selectivities toward CH3OH, HCOOH, and C2 hydrocarbons. Nevertheless, when also considering plasma-generated radicals, we find that these species mainly govern the surface chemistry. Additionally, we find that plasma-generated radicals and stable intermediates enhance the TOFs of COx and oxygenates, increase the selectivity toward oxygenates, and make the formation of HCOOH more significant on Pt(111). We also briefly illustrate the potential impact of Eley−Rideal reactions that involve plasma-generated radicals. Finally, we reveal how various radicals affect the catalyst surface chemistry and we link this to the formation of different products. This allows us to make suggestions on how the plasma composition should be altered to improve the formation of desired products.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000619760700017 Publication Date 2021-02-11
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 1932-7447 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.536 Times cited Open Access OpenAccess
Notes Universiteit Antwerpen; Fonds Wetenschappelijk Onderzoek, S001619N ; H2020 European Research Council, 810182 ; We thank Tom Butterworth for the interesting discussions regarding the calculation of the vibrational populations of methane and for taking the time to share his thoughts and experiences on the matter. This research is supported by the FWO-SBO project PLASMACATDesign (grant number S001619N). We also acknowledge financial support from the TOP-BOF project of the University of Antwerp and from the European Research Council (ERC) under the European Union’s Horizon 2020 Research and Innovation Program (grant agreement no. 810182SCOPE ERC Synergy project). The calculations were carried out using the Turing HPC infrastructure at the CalcUA core facility of the Universiteit Antwerpen, a division of the Flemish Supercomputer Center VSC, funded by the Hercules Foundation, the Flemish Government (Department EWI), and the University of Antwerp. Approved Most recent IF: 4.536
Call Number PLASMANT @ plasmant @c:irua:175873 Serial 6672
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Author Jafarzadeh, A.; Bal, K.M.; Bogaerts, A.; Neyts, E.C.
Title CO2 activation on TiO2-supported Cu5 and Ni5 nanoclusters : effect of plasma-induced surface charging Type A1 Journal article
Year 2019 Publication The journal of physical chemistry: C : nanomaterials and interfaces Abbreviated Journal J Phys Chem C
Volume 123 Issue 11 Pages 6516-6525
Keywords A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Surface charging is an often overlooked factor in many plasma-surface interactions and in particular in plasma catalysis. In this study, we investigate the effect of excess electrons induced by a plasma on the adsorption properties of CO2 on titania-supported Cu-5 and Ni-5 clusters using spin-polarized and dispersion-corrected density functional theory calculations. The effect of excess electrons on the adsorption of Ni and Cu pentamers as well as on CO2 adsorption on a pristine anatase TiO2(101) slab is studied. Our results indicate that adding plasma-induced excess electrons to the system leads to further stabilization of the bent CO2 structure. Also, dissociation of CO2 on charged clusters is energetically more favorable than on neutral clusters. We hypothesize that surface charge is a plausible cause for the synergistic effects sometimes observed in plasma catalysis.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000462260700024 Publication Date 2019-02-21
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 1932-7447; 1932-7455 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.536 Times cited 4 Open Access OpenAccess
Notes Approved Most recent IF: 4.536
Call Number UA @ admin @ c:irua:159422 Serial 5281
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Author Wendelen, W.; Dzhurakhalov, A.A.; Peeters, F.M.; Bogaerts, A.
Title Combined molecular dynamics: continuum study of phase transitions in bulk metals under ultrashort pulsed laser irradiation Type A1 Journal article
Year 2010 Publication The journal of physical chemistry: C : nanomaterials and interfaces Abbreviated Journal J Phys Chem C
Volume 114 Issue 12 Pages 5652-5660
Keywords A1 Journal article; Integrated Molecular Plant Physiology Research (IMPRES); Condensed Matter Theory (CMT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract The phase transition processes induced by ultrashort, 100 fs pulsed laser irradiation of Au, Cu, and Ni are studied by means of a combined atomistic-continuum approach. A moderately low absorbed laser fluence range, from 200 to 600 J/m2 is considered to study phase transitions by means of a local and a nonlocal order parameter. At low laser fluences, the occurrence of layer-by-layer evaporation has been observed, which suggests a direct solid to vapor transition. The calculated amount of molten material remains very limited under the conditions studied, especially for Ni. Therefore, our results show that a kinetic equation that describes a direct solid to vapor transition might be the best approach to model laser-induced phase transitions by continuum models. Furthermore, the results provide more insight into the applicability of analytical superheating theories that were implemented in continuum models and help the understanding of nonequilibrium phase transitions.
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000275855600044 Publication Date 2010-01-26
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 1932-7447;1932-7455; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.536 Times cited 2 Open Access
Notes ; A.D. gratefully acknowledges Professor M. Hot (ULB, Brussels) for the basic MD-code that was modified further for the laser-induced melting processes. W.W, and A.D. are thankful to Professor L.V. Zhigilei for useful discussions and advices. The calculations were performed on the CALCUA computing facility of the University of Antwerp. This work was supported by the Belgian Science Policy (IAP). ; Approved Most recent IF: 4.536; 2010 IF: 4.524
Call Number UA @ lucian @ c:irua:81391 Serial 402
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Author Tinck, S.; Neyts, E.C.; Bogaerts, A.
Title Fluorinesilicon surface reactions during cryogenic and near room temperature etching Type A1 Journal article
Year 2014 Publication The journal of physical chemistry: C : nanomaterials and interfaces Abbreviated Journal J Phys Chem C
Volume 118 Issue 51 Pages 30315-30324
Keywords A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Cyrogenic etching of silicon is envisaged to enable better control over plasma processing in the microelectronics industry, albeit little is known about the fundamental differences compared to the room temperature process. We here present molecular dynamics simulations carried out to obtain sticking probabilities, thermal desorption rates, surface diffusion speeds, and sputter yields of F, F2, Si, SiF, SiF2, SiF3, SiF4, and the corresponding ions on Si(100) and on SiF13 surfaces, both at cryogenic and near room temperature. The different surface behavior during conventional etching and cryoetching is discussed. F2 is found to be relatively reactive compared to other species like SiF03. Thermal desorption occurs at a significantly lower rate under cryogenic conditions, which results in an accumulation of physisorbed species. Moreover, ion incorporation is often observed for ions with energies of 30400 eV, which results in a relatively low net sputter yield. The obtained results suggest that the actual etching of Si, under both cryogenic and near room temperature conditions, is based on the complete conversion of the Si surface to physisorbed SiF4, followed by subsequent sputtering of these molecules, instead of direct sputtering of the SiF03 surface.
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000347360200101 Publication Date 2014-11-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 1932-7447;1932-7455; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.536 Times cited 11 Open Access
Notes Approved Most recent IF: 4.536; 2014 IF: 4.772
Call Number UA @ lucian @ c:irua:122957 Serial 1239
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Author Aerts, R.; Martens, T.; Bogaerts, A.
Title Influence of vibrational states on CO2 splitting by dielectric barrier discharges Type A1 Journal article
Year 2012 Publication The journal of physical chemistry: C : nanomaterials and interfaces Abbreviated Journal J Phys Chem C
Volume 116 Issue 44 Pages 23257-23273
Keywords A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract In this paper, the splitting of CO2 in a pulsed plasma system, such as a dielectric barrier discharge (DBD), is evaluated from a chemical point of view by means of numerical modeling. For this purpose, a chemical reaction set of CO2 in an atmospheric pressure plasma is developed, including the vibrational states of CO2, O2, and CO. The simulated pulses are matched to the conditions of a filament (or microdischarge) and repeated with intervals of 1 μs. The influence of vibrationally excited CO2 as well as other neutral species, ions, and electrons on the CO2 splitting is discussed. Our calculations predict that the electrons have the largest contribution to the CO2 splitting at the conditions under study, by electron impact dissociation. The contribution of vibrationally excited CO2 levels in the splitting of CO2 is found be 6.4%, when only considering one microdischarge pulse and its afterglow, but it can be much higher for consecutive discharge pulses, as is typical for a filamentary DBD, when the interpulse time is short enough and accumulation effects in the vibrationally excited CO2 densities can occur.
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000310769300012 Publication Date 2012-10-19
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 1932-7447;1932-7455; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.536 Times cited 112 Open Access
Notes Approved Most recent IF: 4.536; 2012 IF: 4.814
Call Number UA @ lucian @ c:irua:101764 Serial 1659
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Author Khalilov, U.; Pourtois, G.; Huygh, S.; van Duin, A.C.T.; Neyts, E.C.; Bogaerts, A.
Title New mechanism for oxidation of native silicon oxide Type A1 Journal article
Year 2013 Publication The journal of physical chemistry: C : nanomaterials and interfaces Abbreviated Journal J Phys Chem C
Volume 117 Issue 19 Pages 9819-9825
Keywords A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Continued miniaturization of metal-oxide-semiconductor field-effect transistors (MOSFETs) requires an ever-decreasing thickness of the gate oxide. The structure of ultrathin silicon oxide films, however, critically depends on the oxidation mechanism. Using reactive atomistic simulations, we here demonstrate how the oxidation mechanism in hyperthermal oxidation of such structures may be controlled by the oxidation temperature and the oxidant energy. Specifically, we study the interaction of hyperthermal oxygen with energies of 15 eV with thin SiOx (x ≤ 2) films with a native oxide thickness of about 10 Å. We analyze the oxygen penetration depth probability and compare with results of the hyperthermal oxidation of a bare Si(100){2 × 1} (c-Si) surface. The temperature-dependent oxidation mechanisms are discussed in detail. Our results demonstrate that, at low (i.e., room) temperature, the penetrated oxygen mostly resides in the oxide region rather than at the SiOx|c-Si interface. However, at higher temperatures, starting at around 700 K, oxygen atoms are found to penetrate and to diffuse through the oxide layer followed by reaction at the c-Si boundary. We demonstrate that hyperthermal oxidation resembles thermal oxidation, which can be described by the DealGrove model at high temperatures. Furthermore, defect creation mechanisms that occur during the oxidation process are also analyzed. This study is useful for the fabrication of ultrathin silicon oxide gate oxides for metal-oxide-semiconductor devices as it links parameters that can be straightforwardly controlled in experiment (oxygen temperature, velocity) with the silicon oxide structure.
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000319649100032 Publication Date 2013-04-23
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 1932-7447;1932-7455; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.536 Times cited 24 Open Access
Notes Approved Most recent IF: 4.536; 2013 IF: 4.835
Call Number UA @ lucian @ c:irua:107989 Serial 2321
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Author Kolev, I.; Bogaerts, A.
Title Numerical study of the sputtering in a dc magnetron Type A1 Journal article
Year 2009 Publication Journal of vacuum science and technology: A: vacuum surfaces and films Abbreviated Journal J Phys Chem C
Volume 27 Issue 1 Pages 20-28
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Molecular dynamics simulations were used to investigate the size-dependent melting mechanism of nickel nanoclusters of various sizes. The melting process was monitored by the caloric curve, the overall cluster Lindemann index, and the atomic Lindemann index. Size-dependent melting temperatures were determined, and the correct linear dependence on inverse diameter was recovered. We found that the melting mechanism gradually changes from dynamic coexistence melting to surface melting with increasing cluster size. These findings are of importance in better understanding carbon nanotube growth by catalytic chemical vapor deposition as the phase state of the catalyst nanoparticle codetermines the growth mechanism.
Address
Corporate Author Thesis
Publisher Place of Publication New York, N.Y. Editor
Language Wos 000263299600018 Publication Date 2009-02-03
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 1932-7447;1932-7455; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.536 Times cited 66 Open Access
Notes Approved Most recent IF: 4.536; 2009 IF: 4.224
Call Number UA @ lucian @ c:irua:71634 Serial 2411
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Author De Bie, C.; van Dijk, J.; Bogaerts, A.
Title The Dominant Pathways for the Conversion of Methane into Oxygenates and Syngas in an Atmospheric Pressure Dielectric Barrier Discharge Type A1 Journal article
Year 2015 Publication The journal of physical chemistry: C : nanomaterials and interfaces Abbreviated Journal J Phys Chem C
Volume 119 Issue 119 Pages 22331-22350
Keywords A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract A one-dimensional fluid model for a dielectric barrier discharge in CH4/O2 and CH4/CO2 gas mixtures is developed. The model describes the gas-phase chemistry for partial oxidation and for dry reforming of methane. The spatially averaged densities of the various plasma species are presented as a function of time and initial gas mixing ratio. Besides, the conversion of the inlet gases and the selectivities of the reaction products are calculated. Syngas, higher hydrocarbons, and higher oxygenates are typically found to be important reaction products. Furthermore, the main underlying reaction pathways for the formation of syngas, methanol, formaldehyde, and other higher oxygenates are determined.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000362385700010 Publication Date 2015-09-10
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 1932-7447;1932-7455; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.536 Times cited 46 Open Access
Notes This work was carried out using the Turing HPC infrastructure at the CalcUA core facility of the Universiteit Antwerpen, a division of the Flemish Supercomputer Center VSC, funded by the Hercules Foundation, the Flemish Government (department EWI), and the Universiteit Antwerpen. The authors also acknowledge financial support from the IAP/7 (Interuniversity Attraction Pole) program “PSI-Physical Chemistry of Plasma- Surface Interactions” by the Belgian Federal Office for Science Policy (BELSPO) and from the Fund for Scientific Research Flanders (FWO). Approved Most recent IF: 4.536; 2015 IF: 4.772
Call Number c:irua:128774 Serial 3960
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Author Snoeckx, R.; Aerts, R.; Tu, X.; Bogaerts, A.
Title Plasma-based dry reforming : a computational study ranging from the nanoseconds to seconds time scale Type A1 Journal article
Year 2013 Publication The journal of physical chemistry: C : nanomaterials and interfaces Abbreviated Journal J Phys Chem C
Volume 117 Issue 10 Pages 4957-4970
Keywords A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract We present a computational study for the conversion of CH4 and CO2 into value-added chemicals, i.e., the so-called dry reforming of methane, in a dielectric barrier discharge reactor. A zero-dimensional chemical kinetics model is applied to study the plasma chemistry in a 1:1 CH4/CO2 mixture. The calculations are first performed for one microdischarge pulse and its afterglow, to study in detail the chemical pathways of the conversion. Subsequently, long time-scale simulations are carried out, corresponding to real residence times in the plasma, assuming a large number of consecutive microdischarge pulses, to mimic the conditions of the filamentary discharge regime in a dielectric barrier discharge (DBD) reactor. The conversion of CH4 and CO2 as well as the selectivity of the formed products and the energy cost and energy efficiency of the process are calculated and compared to experiments for a range of different powers and gas flows, and reasonable agreement is reached.
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000316308400010 Publication Date 2013-02-18
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 1932-7447;1932-7455; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.536 Times cited 118 Open Access
Notes Approved Most recent IF: 4.536; 2013 IF: 4.835
Call Number UA @ lucian @ c:irua:106516 Serial 2628
Permanent link to this record
 

 
Author Yusupov, M.; Bogaerts, A.; Huygh, S.; Snoeckx, R.; van Duin, A.C.T.; Neyts, E.C.
Title Plasma-induced destruction of bacterial cell wall components : a reactive molecular dynamics simulation Type A1 Journal article
Year 2013 Publication The journal of physical chemistry: C : nanomaterials and interfaces Abbreviated Journal J Phys Chem C
Volume 117 Issue 11 Pages 5993-5998
Keywords A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Nonthermal atmospheric pressure plasmas are gaining increasing attention for biomedical applications. However, very little fundamental information on the interaction mechanisms between the plasma species and biological cells is currently available. We investigate the interaction of important plasma species, such as OH, H2O2, O, O3, as well as O2 and H2O, with bacterial peptidoglycan by means of reactive molecular dynamics simulations, aiming for a better understanding of plasma disinfection. Our results show that OH, O, O3, and H2O2 can break structurally important bonds of peptidoglycan (i.e., CO, CN, or CC bonds), which consequently leads to the destruction of the bacterial cell wall. The mechanisms behind these breakups are, however, dependent on the impinging plasma species, and this also determines the effectiveness of the cell wall destruction.
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000316773000056 Publication Date 2013-02-23
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 1932-7447;1932-7455; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.536 Times cited 59 Open Access
Notes Approved Most recent IF: 4.536; 2013 IF: 4.835
Call Number UA @ lucian @ c:irua:107154 Serial 2636
Permanent link to this record
 

 
Author Somers, W.; Bogaerts, A.; van Duin, A.C.T.; Neyts, E.C.
Title Plasma species interacting with nickel surfaces : toward an atomic scale understanding of plasma-catalysis Type A1 Journal article
Year 2012 Publication The journal of physical chemistry: C : nanomaterials and interfaces Abbreviated Journal J Phys Chem C
Volume 116 Issue 39 Pages 20958-20965
Keywords A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract The adsorption probability and reaction behavior of CHx plasma species on various nickel catalyst surfaces is investigated by means of reactive molecular dynamics (MD) simulations using the ReaxFF potential. Such catalysts are used in the reforming of hydrocarbons and in the growth of carbon nanotubes, and further insight in the underlying mechanisms of these processes is needed to increase their applicability. Single and consecutive impacts of CHx radicals (x={1,2,3}) were performed on four different Ni surfaces, at a temperature of 400 K. The adsorption probability is shown to be related to the number of free electrons, i.e. a higher number leads to more adsorptions, and the steric hindrance caused by the hydrogen atoms bonded to the impacting CHx species. Furthermore, some of the CH bonds break after adsorption, which generally leads to diffusion of the hydrogen atom over the surface. Additionally, these adsorbed H-atoms can be used in reactions to form new molecules, such as CH4 and C2Hx, although this is dependent on the precise morphology of the surface. New molecules are also formed by subtraction of H-atoms from adsorbed radicals, leading to occasional formation of H2 and C2Hx molecules.
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000309375700040 Publication Date 2012-09-10
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 1932-7447;1932-7455; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.536 Times cited 37 Open Access
Notes Approved Most recent IF: 4.536; 2012 IF: 4.814
Call Number UA @ lucian @ c:irua:101522 Serial 2640
Permanent link to this record
 

 
Author Heijkers, S.; Snoeckx, R.; Kozák, T.; Silva, T.; Godfroid, T.; Britun, N.; Snyders, R.; Bogaerts, A.
Title CO2 conversion in a microwave plasma reactor in the presence of N2 : elucidating the role of vibrational levels Type A1 Journal article
Year 2015 Publication The journal of physical chemistry: C : nanomaterials and interfaces Abbreviated Journal J Phys Chem C
Volume 119 Issue 119 Pages 12815-12828
Keywords A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract A chemical kinetics model is developed for a CO2/N2 microwave plasma, focusing especially on the vibrational levels of both CO2 and N2. The model is used to calculate the CO2 and N2 conversion as well as the energy efficiency of CO2 conversion for different power densities and for N2 fractions in the CO2/N2 gas mixture ranging from 0 to 90%. The calculation results are compared with measurements, and agreements within 23% and 33% are generally found for the CO2 conversion and N2 conversion, respectively. To explain the observed trends, the destruction and formation processes of both CO2 and N2 are analyzed, as well as the vibrational distribution functions of both CO2 and N2. The results indicate that N2 contributes in populating the lower asymmetric levels of CO2, leading to a higher absolute CO2 conversion upon increasing N2 fraction. However, the effective CO2 conversion drops because there is less CO2 initially present in the gas mixture; thus, the energy efficiency also drops with rising N2 fraction.
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000356317500005 Publication Date 2015-05-13
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 1932-7447;1932-7455; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.536 Times cited 56 Open Access
Notes Approved Most recent IF: 4.536; 2015 IF: 4.772
Call Number c:irua:126325 Serial 3523
Permanent link to this record
 

 
Author Khosravian, N.; Bogaerts, A.; Huygh, S.; Yusupov, M.; Neyts, E.C.
Title How do plasma-generated OH radicals react with biofilm components? Insights from atomic scale simulations Type A1 Journal article
Year 2015 Publication Biointerphases Abbreviated Journal Biointerphases
Volume 10 Issue 10 Pages 029501
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract The application of nonthermal atmospheric pressure plasma is emerging as an alternative and efficient technique for the inactivation of bacterial biofilms. In this study, reactive molecular dynamics simulations were used to examine the reaction mechanisms of hydroxyl radicals, as key reactive oxygen plasma species in biological systems, with several organic molecules (i.e., alkane, alcohol, carboxylic acid, and amine), as prototypical components of biomolecules in the biofilm. Our results demonstrate that organic molecules containing hydroxyl and carboxyl groups may act as trapping agents for the OH radicals. Moreover, the impact of OH radicals on N-acetyl-glucosamine, as constituent component of staphylococcus epidermidis biofilms, was investigated. The results show how impacts of OH radicals lead to hydrogen abstraction and subsequent molecular damage. This study thus provides new data on the reaction mechanisms of plasma species, and particularly the OH radicals, with fundamental components of bacterial biofilms.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000357195600019 Publication Date 2014-12-17
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 1934-8630;1559-4106; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.603 Times cited 10 Open Access
Notes Approved Most recent IF: 2.603; 2015 IF: 3.374
Call Number c:irua:121371 Serial 1492
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Author Wende, K.; Williams, P.; Dalluge, J.; Van Gaens, W.; Aboubakr, H.; Bischof, J.; von Woedtke, T.; Goyal, S.M.; Weltmann, K.D.; Bogaerts, A.; Masur, K.; Bruggeman, P.J.;
Title Identification of the biologically active liquid chemistry induced by a nonthermal atmospheric pressure plasma jet Type A1 Journal article
Year 2015 Publication Biointerphases Abbreviated Journal Biointerphases
Volume 10 Issue 10 Pages 029518
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract The mechanism of interaction of cold nonequilibrium plasma jets with mammalian cells in physiologic liquid is reported. The major biological active species produced by an argon RF plasma jet responsible for cell viability reduction are analyzed by experimental results obtained through physical, biological, and chemical diagnostics. This is complemented with chemical kinetics modeling of the plasma source to assess the dominant reactive gas phase species. Different plasma chemistries are obtained by changing the feed gas composition of the cold argon based RF plasma jet from argon, humidified argon (0.27%), to argon/oxygen (1%) and argon/air (1%) at constant power. A minimal consensus physiologic liquid was used, providing isotonic and isohydric conditions and nutrients but is devoid of scavengers or serum constituents. While argon and humidified argon plasma led to the creation of hydrogen peroxide dominated action on the mammalian cells, argonoxygen and argonair plasma created a very different biological action and was characterized by trace amounts of hydrogen peroxide only. In particular, for the argonoxygen (1%), the authors observed a strong negative effect on mammalian cell proliferation and metabolism. This effect was distance dependent and showed a half life time of 30 min in a scavenger free physiologic buffer. Neither catalase and mannitol nor superoxide dismutase could rescue the cell proliferation rate. The strong distance dependency of the effect as well as the low water solubility rules out a major role for ozone and singlet oxygen but suggests a dominant role of atomic oxygen. Experimental results suggest that O reacts with chloride, yielding Cl2 − or ClO−. These chlorine species have a limited lifetime under physiologic conditions and therefore show a strong time dependent biological activity. The outcomes are compared with an argon MHz plasma jet (kinpen) to assess the differences between these (at least seemingly) similar plasma sources.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000357195600036 Publication Date 2015-05-06
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 1934-8630;1559-4106; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.603 Times cited 137 Open Access
Notes Approved Most recent IF: 2.603; 2015 IF: 3.374
Call Number c:irua:126774 Serial 1549
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Author Neyts, E.C.; Shibuta, Y.; van Duin, A.C.T.; Bogaerts, A.
Title Catalyzed growth of carbon nanotube with definable chirality by hybrid molecular dynamics-force biased Monte Carlo simulations Type A1 Journal article
Year 2010 Publication ACS nano Abbreviated Journal Acs Nano
Volume 4 Issue 11 Pages 6665-6672
Keywords A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Metal-catalyzed growth mechanisms of carbon nanotubes (CNTs) were studied by hybrid molecular dynamics−Monte Carlo simulations using a recently developed ReaxFF reactive force field. Using this novel approach, including relaxation effects, a CNT with definable chirality is obtained, and a step-by-step atomistic description of the nucleation process is presented. Both root and tip growth mechanisms are observed. The importance of the relaxation of the network is highlighted by the observed healing of defects.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000284438000043 Publication Date 2010-10-12
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 1936-0851;1936-086X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 13.942 Times cited 129 Open Access
Notes Approved Most recent IF: 13.942; 2010 IF: 9.865
Call Number UA @ lucian @ c:irua:84759 Serial 294
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Author Neyts, E.C.; Bogaerts, A.
Title Modeling the growth of SWNTs and graphene on the atomic scale Type A1 Journal article
Year 2012 Publication ECS transactions Abbreviated Journal
Volume 45 Issue 4 Pages 73-78
Keywords A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract The possibility of application of nanomaterials is determined by our ability to control the properties of the materials, which are ultimately determined by their structure and hence their growth processes. We employ hybrid molecular dynamics / Monte Carlo (MD/MC) simulations to explore the growth of SWNTs and graphene on nickel as a catalyst, with the specific goal of unraveling the growth mechanisms. While the general observations are in agreement with the literature, we find a number of interesting phenomena to be operative which are crucial for the growth, and which are not accessible by MD simulations alone due to the associated time scale. Specifically, we observe metal mediated healing and restructuring processes to take place, reorganizing the carbon network during the initial nucleation step. In the case of carbon nanotube growth, this leads to the growth of tubes with a determinable chirality. In the case of graphene formation, we find that graphene is only formed at temperatures above 700 K. These results are of importance for understanding the growth mechanisms of these carbon nanomaterials on the fundamental level.
Address
Corporate Author Thesis
Publisher Electrochemical Society Place of Publication Pennington Editor
Language Wos 000316890000008 Publication Date 2012-04-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 1938-6737;1938-5862; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited 2 Open Access
Notes Approved Most recent IF: NA
Call Number UA @ lucian @ c:irua:108535 Serial 2144
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