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Author Mees, M.J.; Pourtois, G.; Neyts, E.C.; Thijsse, B.J.; Stesmans, A.
Title Uniform-acceptance force-bias Monte Carlo method with time scale to study solid-state diffusion Type A1 Journal article
Year 2012 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 85 Issue 13 Pages 134301-134301,9
Keywords (up) A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Monte Carlo (MC) methods have a long-standing history as partners of molecular dynamics (MD) to simulate the evolution of materials at the atomic scale. Among these techniques, the uniform-acceptance force-bias Monte Carlo (UFMC) method [ G. Dereli Mol. Simul. 8 351 (1992)] has recently attracted attention [ M. Timonova et al. Phys. Rev. B 81 144107 (2010)] thanks to its apparent capacity of being able to simulate physical processes in a reduced number of iterations compared to classical MD methods. The origin of this efficiency remains, however, unclear. In this work we derive a UFMC method starting from basic thermodynamic principles, which leads to an intuitive and unambiguous formalism. The approach includes a statistically relevant time step per Monte Carlo iteration, showing a significant speed-up compared to MD simulations. This time-stamped force-bias Monte Carlo (tfMC) formalism is tested on both simple one-dimensional and three-dimensional systems. Both test-cases give excellent results in agreement with analytical solutions and literature reports. The inclusion of a time scale, the simplicity of the method, and the enhancement of the time step compared to classical MD methods make this method very appealing for studying the dynamics of many-particle systems.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000302290500001 Publication Date 2012-04-03
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 31 Open Access
Notes Approved Most recent IF: 3.836; 2012 IF: 3.767
Call Number UA @ lucian @ c:irua:97160 Serial 3809
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Author Zhang, Y.-R.; Van Laer, K.; Neyts, E.C.; Bogaerts, A.
Title Can plasma be formed in catalyst pores? A modeling investigation Type A1 Journal article
Year 2016 Publication Applied catalysis : B : environmental Abbreviated Journal Appl Catal B-Environ
Volume 185 Issue 185 Pages 56-67
Keywords (up) A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract tWe investigate microdischarge formation inside catalyst pores by a two-dimensional fluid model forvarious pore sizes in the m-range and for various applied voltages. Indeed, this is a poorly understoodphenomenon in plasma catalysis. The calculations are performed for a dielectric barrier discharge inhelium, at atmospheric pressure. The electron and ion densities, electron temperature, electric field andpotential, as well as the electron impact ionization and excitation rate and the densities of excited plasmaspecies, are examined for a better understanding of the characteristics of the plasma inside a pore. Theresults indicate that the pore size and the applied voltage are critical parameters for the formation of amicrodischarge inside a pore. At an applied voltage of 20 kV, our calculations reveal that the ionizationmainly takes place inside the pore, and the electron density shows a significant increase near and inthe pore for pore sizes larger than 200m, whereas the effect of the pore on the total ion density isevident even for 10m pores. When the pore size is fixed at 30m, the presence of the pore has nosignificant influence on the plasma properties at an applied voltage of 2 kV. Upon increasing the voltage,the ionization process is enhanced due to the strong electric field and high electron temperature, andthe ion density shows a remarkable increase near and in the pore for voltages above 10 kV. These resultsindicate that the plasma species can be formed inside pores of structured catalysts (in the m range),and they may interact with the catalyst surface, and affect the plasma catalytic process.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000369452000006 Publication Date 2015-12-11
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0926-3373 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 9.446 Times cited 75 Open Access
Notes This work was supported by the Fund for Scientific ResearchFlanders (FWO) (Grant no. G.0217.14N), the National Natural Sci-ence Foundation of China (Grant no. 11405019), and the ChinaPostdoctoral Science Foundation (Grant no. 2015T80244). Theauthors are very grateful to V. Meynen for the useful discussions oncatalysts. This work was carried out in part using the Turing HPCinfrastructure at the CalcUA core facility of the Universiteit Antwer-pen, a division of the Flemish Supercomputer Center VSC, fundedby the Hercules Foundation, the Flemish Government (departmentEWI) and the University of Antwerp. Approved Most recent IF: 9.446
Call Number c:irua:129808 Serial 3984
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Author Bogaerts, A.; Khosravian, N.; Van der Paal, J.; Verlackt, C.C.W.; Yusupov, M.; Kamaraj, B.; Neyts, E.C.
Title Multi-level molecular modelling for plasma medicine Type A1 Journal article
Year 2016 Publication Journal of physics: D: applied physics Abbreviated Journal J Phys D Appl Phys
Volume 49 Issue 49 Pages 054002
Keywords (up) A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Modelling at the molecular or atomic scale can be very useful for obtaining a better insight in plasma medicine. This paper gives an overview of different atomic/molecular scale modelling approaches that can be used to study the direct interaction of plasma species with biomolecules or the consequences of these interactions for the biomolecules on a somewhat longer time-scale. These approaches include density functional theory (DFT), density functional based tight binding (DFTB), classical reactive and non-reactive molecular dynamics (MD) and united-atom or coarse-grained MD, as well as hybrid quantum mechanics/molecular mechanics (QM/MM) methods. Specific examples will be given for three important types of biomolecules, present in human cells, i.e. proteins, DNA and phospholipids found in the cell membrane. The results show that each of these modelling approaches has its specific strengths and limitations, and is particularly useful for certain applications. A multi-level approach is therefore most suitable for obtaining a global picture of the plasma–biomolecule interactions.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000368944100003 Publication Date 2015-12-16
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0022-3727 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.588 Times cited 11 Open Access
Notes This work is financially supported by the Fund for Scientific Research Flanders (FWO) and the Francqui Foundation. The calculations were carried out in part using the Turing HPC infrastructure of 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. Approved Most recent IF: 2.588
Call Number c:irua:131571 Serial 3985
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Author Van der Paal, J.; Neyts, E.C.; Verlackt, C.C.W.; Bogaerts, A.
Title Effect of lipid peroxidation on membrane permeability of cancer and normal cells subjected to oxidative stress Type A1 Journal article
Year 2016 Publication Chemical science Abbreviated Journal Chem Sci
Volume 7 Issue 7 Pages 489-498
Keywords (up) A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract We performed molecular dynamics simulations to investigate the effect of lipid peroxidation products on the structural and dynamic properties of the cell membrane. Our simulations predict that the lipid order in a phospholipid bilayer, as a model system for the cell membrane, decreases upon addition of lipid peroxidation products. Eventually, when all phospholipids are oxidized, pore formation can occur. This will allow reactive species, such as reactive oxygen and nitrogen species (RONS), to enter the cell and cause oxidative damage to intracellular macromolecules, such as DNA or proteins. On the other hand, upon increasing the cholesterol fraction of lipid bilayers, the cell membrane order increases, eventually reaching a certain threshold, from which cholesterol is able to protect the membrane against pore formation. This finding is crucial for cancer treatment by plasma technology, producing a large number of RONS, as well as for other cancer treatment methods that cause an increase in the concentration of extracellular RONS. Indeed, cancer cells contain less cholesterol than their healthy counterparts. Thus, they will be more vulnerable to the consequences of lipid peroxidation, eventually enabling the penetration of RONS into the interior of the cell, giving rise to oxidative stress, inducing pro-apoptotic factors. This provides, for the first time, molecular level insight why plasma can selectively treat cancer cells, while leaving their healthy counterparts undamaged, as is indeed experimentally demonstrated.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000366826900058 Publication Date 2015-10-16
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2041-6520 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 8.668 Times cited 106 Open Access
Notes The authors acknowledge nancial support from the Fund for Scientic Research (FWO) Flanders, grant number G012413N. The calculations were performed in part using the Turing HPC infrastructure of 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. Approved Most recent IF: 8.668
Call Number c:irua:131058 Serial 3986
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Author Bal, K.M.; Neyts, E.C.
Title Merging Metadynamics into Hyperdynamics: Accelerated Molecular Simulations Reaching Time Scales from Microseconds to Seconds Type A1 Journal article
Year 2015 Publication Journal of chemical theory and computation Abbreviated Journal J Chem Theory Comput
Volume 11 Issue 11 Pages 4545-4554
Keywords (up) A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract The hyperdynamics method is a powerful tool to simulate slow processes at the atomic level. However, the construction of an optimal hyperdynamics potential is a task that is far from trivial. Here, we propose a generally applicable implementation of the hyperdynamics algorithm, borrowing two concepts from metadynamics. First, the use of a collective variable (CV) to represent the accelerated dynamics gives the method a very large flexibility and simplicity. Second, a metadynamics procedure can be used to construct a suitable history-dependent bias potential on-the-fly, effectively turning the algorithm into a self-learning accelerated molecular dynamics method. This collective variable-driven hyperdynamics (CVHD) method has a modular design: both the local system properties on which the bias is based, as well as the characteristics of the biasing method itself, can be chosen to match the needs of the considered system. As a result, system-specific details are abstracted from the biasing algorithm itself, making it extremely versatile and transparent. The method is tested on three model systems: diffusion on the Cu(001) surface and nickel-catalyzed methane decomposition, as examples of reactive processes with a bond-length-based CV, and the folding of a long polymer-like chain, using a set of dihedral angles as a CV. Boost factors up to 109, corresponding to a time scale of seconds, could be obtained while still accurately reproducing correct dynamics.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000362921700004 Publication Date 2015-09-02
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1549-9618 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 5.245 Times cited 41 Open Access
Notes K.M.B. is funded as Ph.D. fellow (aspirant) of the FWOFlanders (Fund for Scientific Research-Flanders), Grant No. 11 V8915N. The computational resources and services used in this work were provided by the VSC (Flemish Supercomputer Center) and the HPC infrastructure of the University of Antwerp (CalcUA), funded by the Hercules Foundation and the Flemish Government−Department EWI. Approved Most recent IF: 5.245; 2015 IF: 5.498
Call Number c:irua:128183 Serial 3991
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Author Neyts, E.C.; Ostrikov, K.K.; Sunkara, M.K.; Bogaerts, A.
Title Plasma Catalysis: Synergistic Effects at the Nanoscale Type A1 Journal article
Year 2015 Publication Chemical reviews Abbreviated Journal Chem Rev
Volume 115 Issue 115 Pages 13408-13446
Keywords (up) A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Thermal-catalytic gas processing is integral to many current industrial processes. Ever-increasing demands on conversion and energy efficiencies are a strong driving force for the development of alternative approaches. Similarly, synthesis of several functional materials (such as nanowires and nanotubes) demands special processing conditions. Plasma catalysis provides such an alternative, where the catalytic process is complemented by the use of plasmas that activate the source gas. This combination is often observed to result in a synergy between plasma and catalyst. This Review introduces the current state-of-the-art in plasma catalysis, including numerous examples where plasma catalysis has demonstrated its benefits or shows future potential, including CO2 conversion, hydrocarbon reforming, synthesis of nanomaterials, ammonia production, and abatement of toxic waste gases. The underlying mechanisms governing these applications, as resulting from the interaction between the plasma and the catalyst, render the process highly complex, and little is known about the factors leading to the often-observed synergy. This Review critically examines the catalytic mechanisms relevant to each specific application.
Address Department of Chemistry, Research Group PLASMANT, Universiteit Antwerpen , Universiteitsplein 1, 2610 Wilrijk-Antwerp, Belgium
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Wos 000367563000006 Publication Date 2015-11-30
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0009-2665 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 47.928 Times cited 204 Open Access
Notes ECN and AB gratefully acknowledge financial support from the Fund of Scientific Research Flanders (FWO), Belgium, Grant Number G.0217.14N. KO acknowledges partial support by the Australian Research Council and CSIRO’s OCE Science Leaders Program. MKS acknowledges partial support from US National Science Foundation through grants DMS 1125909 and EPSCoR 1355448 and also PhD students Babajide Ajayi, Apolo Nambo and Maria Carreon for their help. Approved Most recent IF: 47.928; 2015 IF: 46.568
Call Number c:irua:130001 Serial 3993
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Author Neyts, E.C.
Title Plasma-Surface Interactions in Plasma Catalysis Type A1 Journal article
Year 2016 Publication Plasma chemistry and plasma processing Abbreviated Journal Plasma Chem Plasma P
Volume 36 Issue 36 Pages 185-212
Keywords (up) A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract In this paper the various elementary plasma—surface interaction processes occurring in plasma catalysis are critically evaluated. Specifically, plasma catalysis at atmospheric pressure is considered. The importance of the various processes is analyzed for the most common plasma catalysis sources, viz. the dielectric barrier discharge and the gliding arc. The role and importance of surface chemical reactions (including adsorption, surface-mediated association and dissociation reactions, and desorption), plasma-induced surface modification, photocatalyst activation, heating, charging, surface discharge formation and electric field enhancement are discussed in the context of plasma catalysis. Numerous examples are provided to demonstrate the importance of the various processes.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000370720800011 Publication Date 2015-10-16
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0272-4324 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.355 Times cited 66 Open Access
Notes The author is indebted to many colleagues for fruitful discussions. In particular discussions with A. Bogaerts (University of Antwerp, Belgium), H.-H. Kim (AIST, Japan), J. C. Whitehead (University of Manchester, UK) and T. Nozaki (Tokyo Institute of Technology, Japan) are greatfully acknowledged and appreciated. Approved Most recent IF: 2.355
Call Number c:irua:130742 Serial 4004
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Author Bal, K.M.; Neyts, E.C.
Title Direct observation of realistic-temperature fuel combustion mechanisms in atomistic simulations Type A1 Journal article
Year 2016 Publication Chemical science Abbreviated Journal Chem Sci
Volume 7 Issue 7 Pages 5280-5286
Keywords (up) A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Atomistic simulations can in principle provide an unbiased description of all mechanisms, intermediates, and products of complex chemical processes. However, due to the severe time scale limitation of conventional simulation techniques, unrealistically high simulation temperatures are usually applied, which are a poor approximation of most practically relevant low-temperature applications. In this work, we demonstrate the direct observation at the atomic scale of the pyrolysis and oxidation of n-dodecane at temperatures as low as 700 K through the use of a novel simulation technique, collective variable-driven hyperdynamics (CVHD). A simulated timescale of up to 39 seconds is reached. Product compositions and dominant mechanisms are found to be strongly temperature-dependent, and are consistent with experiments and kinetic models. These simulations provide a first atomic-level look at the full dynamics of the complicated fuel combustion process at industrially relevant temperatures and time scales, unattainable by conventional molecular dynamics simulations.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000380893900059 Publication Date 2016-05-05
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2041-6520 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 8.668 Times cited 22 Open Access
Notes K. M. B. is funded as PhD fellow (aspirant) of the FWO-Flanders (Fund for Scientic Research-Flanders), Grant 11V8915N. The computational resources and services used in this work were provided by the VSC (Flemish Supercomputer Center) and the HPC infrastructure of the University of Antwerp (CalcUA), funded by the Hercules Foundation and the Flemish Government – department EWI. The authors would also like to thank S. Banerjee for assisting with the interpretation of the experimental results. Approved Most recent IF: 8.668
Call Number c:irua:134577 c:irua:135670 Serial 4105
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Author Tinck, S.; Tillocher, T.; Dussart, R.; Neyts, E.C.; Bogaerts, A.
Title Elucidating the effects of gas flow rate on an SF6inductively coupled plasma and on the silicon etch rate, by a combined experimental and theoretical investigation Type A1 Journal article
Year 2016 Publication Journal of physics: D: applied physics Abbreviated Journal J Phys D Appl Phys
Volume 49 Issue 49 Pages 385201
Keywords (up) A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Experiments show that the etch rate of Si with SF6 inductively coupled plasma (ICP) is significantly influenced by the absolute gas flow rate in the range of 50–600 sccm, with a maximum at around 200 sccm. Therefore, we numerically investigate the effects of the gas flow rate on the bulk plasma properties and on the etch rate, to obtain more insight in the underlying reasons of this effect. A hybrid Monte Carlo—fluid model is applied to simulate an SF6 ICP. It is found that the etch rate is influenced by two simultaneous effects: (i) the residence time of the gas and (ii) the temperature profile of the plasma in the ICP volume, resulting indeed in a maximum etch rate at 200 sccm.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000384095900011 Publication Date 2016-08-24
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0022-3727 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.588 Times cited 1 Open Access
Notes We are very grateful to Mark Kushner for providing the computational model. The Fund for Scientific Research Flanders (FWO; grant no. 0880.212.840) is acknowledged for financial support of this work. The 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: 2.588
Call Number c:irua:134867 Serial 4108
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Author Heyne, M.H.; Chiappe, D.; Meersschaut, J.; Nuytten, T.; Conard, T.; Bender, H.; Huyghebaert, C.; Radu, I.P.; Caymax, M.; de Marneffe, J.F.; Neyts, E.C.; De Gendt, S.;
Title Multilayer MoS2 growth by metal and metal oxide sulfurization Type A1 Journal article
Year 2016 Publication Journal of materials chemistry C : materials for optical and electronic devices Abbreviated Journal J Mater Chem C
Volume 4 Issue 4 Pages 1295-1304
Keywords (up) A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract We investigated the deposition of MoS2 multilayers on large area substrates. The pre-deposition of metal or metal oxide with subsequent sulfurization is a promising technique to achieve layered films. We distinguish a different reaction behavior in metal oxide and metallic films and investigate the effect of the temperature, the H2S/H-2 gas mixture composition, and the role of the underlying substrate on the material quality. The results of the experiments suggest a MoS2 growth mechanism consisting of two subsequent process steps. At first, the reaction of the sulfur precursor with the metal or metal oxide occurs, requiring higher temperatures in the case of metallic film compared to metal oxide. At this stage, the basal planes assemble towards the diffusion direction of the reaction educts and products. After the sulfurization reaction, the material recrystallizes and the basal planes rearrange parallel to the substrate to minimize the surface energy. Therefore, substrates with low roughness show basal plane assembly parallel to the substrate. These results indicate that the substrate character has a significant impact on the assembly of low dimensional MoS2 films.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000370723300020 Publication Date 2016-01-05
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2050-7526; 2050-7534 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 5.256 Times cited Open Access
Notes Approved Most recent IF: 5.256
Call Number UA @ lucian @ c:irua:132327 Serial 4211
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Author Neyts, E.C.
Title The role of ions in plasma catalytic carbon nanotube growth : a review Type A1 Journal article
Year 2015 Publication Frontiers of Chemical Science and Engineering Abbreviated Journal Front Chem Sci Eng
Volume 9 Issue 9 Pages 154-162
Keywords (up) A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract While it is well-known that the plasma-enhanced catalytic chemical vapor deposition (PECVD) of carbon nanotubes (CNTs) offers a number of advantages over thermal CVD, the influence of the various individual contributing factors is not well understood. Especially the role of ions is unclear, since ions in plasmas are generally associated with sputtering rather than with growing a material. Even so, various studies have demonstrated the beneficial effects of ion bombardment during the growth of CNTs. This review looks at the role of the ions in plasma-enhanced CNT growth as deduced from both experimental and simulation studies. Specific attention is paid to the beneficial effects of ion bombardment. Based on the available literature, it can be concluded that ions can be either beneficial or detrimental for carbon nanotube growth, depending on the exact conditions and the control over the growth process.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000360319600003 Publication Date 2015-06-11
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2095-0179 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.712 Times cited 8 Open Access
Notes Approved Most recent IF: 1.712; 2015 IF: NA
Call Number UA @ lucian @ c:irua:127815 Serial 4239
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Author Ali, S.; Myasnichenko, V.S.; Neyts, E.C.
Title Size-dependent strain and surface energies of gold nanoclusters Type A1 Journal article
Year 2016 Publication Physical chemistry, chemical physics Abbreviated Journal Phys Chem Chem Phys
Volume 18 Issue 18 Pages 792-800
Keywords (up) A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Gold nanocluster properties exhibit unique size-dependence. In this contribution, we employ reactive molecular dynamics simulations to calculate the size- and temperature-dependent surface energies, strain energies and atomic displacements for icosahedral, cuboctahedral, truncated octahedral and decahedral Au-nanoclusters. The calculations demonstrate that the surface energy decreases with increasing cluster size at 0 K but increases with size at higher temperatures. The calculated melting curves as a function of cluster size demonstrate the Gibbs-Thomson effect. Atomic displacements and strain are found to strongly depend on the cluster size and both are found to increase with increasing cluster size. These results are of importance for understanding the size-and temperature-dependent surface processes on gold nanoclusters.
Address
Corporate Author Thesis
Publisher Place of Publication Cambridge Editor
Language Wos 000369480600017 Publication Date 2015-11-18
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1463-9076 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.123 Times cited 37 Open Access
Notes Approved Most recent IF: 4.123
Call Number UA @ lucian @ c:irua:131626 Serial 4243
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Author Zhang, Y.-R.; Neyts, E.C.; Bogaerts, A.
Title Influence of the Material Dielectric Constant on Plasma Generation inside Catalyst Pores Type A1 Journal article
Year 2016 Publication The journal of physical chemistry: C : nanomaterials and interfaces Abbreviated Journal J Phys Chem C
Volume 120 Issue 120 Pages 25923-25934
Keywords (up) A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Plasma catalysis is gaining increasing interest for various environmental applications, but the crucial question is whether plasma can be created inside catalyst pores and under which conditions. In practice, various catalytic support materials are used, with various dielectric constants. We investigate here the influence of the dielectric constant on the plasma properties inside catalyst pores and in the sheath in front of the pores, for various pore sizes. The calculations are performed by a two-dimensional fluid model for an atmospheric pressure dielectric barrier discharge in helium. The electron impact ionization rate, electron temperature, electron and ion density, as well as the potential distribution and surface charge density, are analyzed for a better understanding of the discharge behavior inside catalyst pores. The results indicate that, in a 100 μm pore, the electron impact ionization in the pore, which is characteristic for the plasma generation inside the pore, is greatly enhanced for dielectric constants below 300. Smaller pore sizes only yield enhanced ionization for smaller dielectric constants, i.e., up to εr = 200, 150, and 50 for pore sizes of 50, 30, and 10 μm. Thus, the most common catalyst supports, i.e., Al2O3 and SiO2, which have dielectric constants around εr = 8−11 and 4.2, respectively, should allow more easily that microdischarges can be formed inside catalyst pores, even for smaller pore sizes. On the other hand, ferroelectric materials with dielectric constants above 300 never seem to yield plasma enhancement inside catalyst pores, not even for 100 μm pore sizes. Furthermore, it is clear that the dielectric constant of the material has a large effect on the extent of plasma enhancement inside the catalyst pores, especially in the range between εr = 4 and εr = 200. The obtained results are explained in detail based on the surface charge density at the pore walls,

and the potential distribution and electron temperature inside and above the pores. The results obtained with this model are

important for plasma catalysis, as the production plasma species in catalyst pores might affect the catalyst properties, and thus

improve the applications of plasma catalysis.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000388429100029 Publication Date 2016-11-17
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 34 Open Access
Notes This work was supported by the Fund for Scientific Research Flanders (FWO) (Grant G.0217.14N), the National Natural Science Foundation of China (Grant 11405019), and the China Postdoctoral Science Foundation (Grant 2015T80244). 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: 4.536
Call Number PLASMANT @ plasmant @ c:irua:138602 Serial 4319
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Author Shirazi, M.; Neyts, E.C.; Bogaerts, A.
Title DFT study of Ni-catalyzed plasma dry reforming of methane Type A1 Journal article
Year 2017 Publication Applied catalysis : B : environmental Abbreviated Journal Appl Catal B-Environ
Volume 205 Issue 205 Pages 605-614
Keywords (up) A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract tWe investigated the plasma-assisted catalytic reactions for the production of value-added chemicalsfrom Ni-catalyzed plasma dry reforming of methane by means of density functional theory (DFT). Weinspected many activation barriers, from the early stage of adsorption of the major chemical fragmentsderived fromCH4andCO2molecules up to the formation of value-added chemicals at the surface, focusingon the formation of methanol, as well as the hydrogenation of C1and C2hydrocarbon fragments. Theactivation barrier calculations show that the presence of surface-bound H atoms and in some cases alsoremaining chemical fragments at the surface facilitates the formation of products. This implies that thehydrogenation of a chemical fragment on the hydrogenated crystalline surface is energetically favouredcompared to the simple hydrogenation of the chemical fragment at the bare Ni(111) surface. Indeed, thepresence of hydrogen modifies the electronic structure of the surface and the course of the reactions.We therefore conclude that surface-bound H atoms, and to some extent also the remaining chemicalfragments at the crystalline surface, induce the following effects: they facilitate associative desorption ofmethanol and ethane by increasing the rate of H-transfer to the adsorbed fragments while they impedehydrogenation of ethylene to ethane, thus promoting again the desorption of ethylene. Overall, they thusfacilitate the catalytic conversion of the formed fragments from CH4and CO2, into value-added chemicals.Finally, we believe that the retention of methane fragments, especially CH3, in the presence of surface-boundHatoms (as observed here for Ni) can be regarded as an identifier for the proper choice of a catalystfor the production of value-added chemicals.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000393931000063 Publication Date 2017-01-05
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0926-3373 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 9.446 Times cited 26 Open Access OpenAccess
Notes Financial support from the Reactive Atmospheric Plasmaprocessing –eDucation network (RAPID), through the EU 7thFramework Programme (grant agreement no. 606889) is grate-fully acknowledged. The calculations were performed using theTuring HPC infrastructure at the CalcUA core facility of the Univer-siteit Antwerpen, a division of the Flemish Supercomputer CenterVSC, funded by the Hercules Foundation, the Flemish Approved Most recent IF: 9.446
Call Number PLASMANT @ plasmant @ c:irua:139514 Serial 4343
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Author Yusupov, M.; Van der Paal, J.; Neyts, E.C.; Bogaerts, A.
Title Synergistic effect of electric field and lipid oxidation on the permeability of cell membranes Type A1 Journal article
Year 2017 Publication Biochimica et biophysica acta : G : general subjects Abbreviated Journal Bba-Gen Subjects
Volume 1861 Issue 1861 Pages 839-847
Keywords (up) A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Background: Strong electric fields are knownto affect cell membrane permeability,which can be applied for therapeutic purposes, e.g., in cancer therapy. A synergistic enhancement of this effect may be accomplished by the presence of reactive oxygen species (ROS), as generated in cold atmospheric plasmas. Little is known about the synergy between lipid oxidation by ROS and the electric field, nor on howthis affects the cell membrane permeability.

Method: We here conduct molecular dynamics simulations to elucidate the dynamics of the permeation process under the influence of combined lipid oxidation and electroporation. A phospholipid bilayer (PLB), consisting of di-oleoyl-phosphatidylcholine molecules covered with water layers, is used as a model system for the plasma membrane.

Results and conclusions:Weshow howoxidation of the lipids in the PLB leads to an increase of the permeability of the bilayer to ROS, although the permeation free energy barriers still remain relatively high. More importantly, oxidation of the lipids results in a drop of the electric field threshold needed for pore formation (i.e., electroporation) in the PLB. The created pores in the membrane facilitate the penetration of reactive plasma species deep into the cell interior, eventually causing oxidative damage.

General significance: This study is of particular interest for plasma medicine, as plasma generates both ROS and electric fields, but it is also of more general interest for applications where strong electric fields and ROS both come into play.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000397366200012 Publication Date 2017-01-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0304-4165 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.702 Times cited Open Access OpenAccess
Notes This work is financially supported by the Fund for Scientific Research Flanders (FWO; grant numbers: 1200216N and 11U5416N). The work was carried out using the Turing HPC infrastructure of the CalcUA core facility of the Universiteit Antwerpen, a division of the Flemish Supercomputer Center VSC, funded by the Hercules Foundation, the Flem Approved Most recent IF: 4.702
Call Number PLASMANT @ plasmant @ c:irua:140095 Serial 4413
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Author Verlackt, C.C.W.; Neyts, E.C.; Bogaerts, A.
Title Atomic scale behavior of oxygen-based radicals in water Type A1 Journal article
Year 2017 Publication Journal of physics: D: applied physics Abbreviated Journal J Phys D Appl Phys
Volume 50 Issue 50 Pages 11LT01
Keywords (up) A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Cold atmospheric pressure plasmas in and in contact with liquids represent a growing field of research for various applications. Understanding the interactions between the plasma generated species and the liquid is crucial. In this work we perform molecular dynamics (MD) simulations based on a quantum mechanical method, i.e. density-functional based tight-binding (DFTB), to examine the interactions of OH radicals and O atoms in bulk water. Our calculations reveal that the transport of OH radicals through water is not only governed by diffusion, but also by an equilibrium reaction of H-abstraction with water molecules. Furthermore, when two OH radicals encounter each other, they either form a stable cluster, or react, resulting in the formation of a new water molecule and an O atom. In addition,

the O atoms form either oxywater (when in singlet configuration) or they remain stable in solution (when in triplet configuration), stressing the important role that O atoms can play in aqueous solution, and in contact with biomolecules. Our observations are in line with both experimental and ab initio results from the literature.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000415252400001 Publication Date 2017-02-13
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0022-3727 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.588 Times cited 11 Open Access OpenAccess
Notes The authors thank Peter Bruggeman (University of Minnesota, USA) and Jan Benedikt (Ruhr-Universität Bochum, Germany) for the interesting discussions regarding the existence of O in aqueous solutions. Furthermore, they acknowledge financial support from the Fund for Scientific Research (FWO) Flanders (project number G012413N). The calculations were performed 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. Approved Most recent IF: 2.588
Call Number PLASMANT @ plasmant @ c:irua:140845 Serial 4420
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Author Neyts, E.C.; Brault, P.
Title Molecular Dynamics Simulations for Plasma-Surface Interactions: Molecular Dynamics Simulations… Type A1 Journal article
Year 2017 Publication Plasma processes and polymers Abbreviated Journal Plasma Process Polym
Volume 14 Issue 14 Pages 1600145
Keywords (up) A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Plasma-surface interactions are in general highly complex due to the interplay of many concurrent processes. Molecular dynamics simulations provide insight in some of these processes, subject to the accessible time and length scales, and the availability of suitable force fields. In this introductory tutorial-style review, we aim to describe the current capabilities and limitations of molecular dynamics simulations in this field, restricting ourselves to low-temperature nonthermal plasmas. Attention is paid to the simulation of the various fundamental processes occurring, including sputtering, etching, implantation, and deposition, as well as to what extent the basic plasma components can be accounted for, including ground state and excited species, electric fields, ions, photons, and electrons. A number of examples is provided, giving an bird’s eye overview of the current state of the field.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000393184600009 Publication Date 2016-09-07
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1612-8850 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.846 Times cited 13 Open Access Not_Open_Access
Notes Approved Most recent IF: 2.846
Call Number PLASMANT @ plasmant @ c:irua:141758 Serial 4488
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Author Khalilov, U.; Bogaerts, A.; Neyts, E.C.
Title Atomic-scale mechanisms of plasma-assisted elimination of nascent base-grown carbon nanotubes Type A1 Journal article
Year 2017 Publication Carbon Abbreviated Journal Carbon
Volume 118 Issue 118 Pages 452-457
Keywords (up) A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Selective etching allows for obtaining carbon nanotubes with a specific chirality. While plasma-assisted etching has already been used to separate metallic tubes from their semiconducting counterparts, little is known about the nanoscale mechanisms of the etching process. We combine (reactive) molecular dynamics (MD) and force-bias Monte Carlo (tfMC) simulations to study H-etching of CNTs. In particular, during the hydrogenation and subsequent etching of both the carbon cap and the tube, they sequentially transform to different carbon nanostructures, including carbon nanosheet, nanowall, and polyyne chains, before they are completely removed from the surface of a substrate-bound Ni-nanocluster.We also found that onset of the etching process is different in the cases of the cap and the tube, although the overall etching scenario is similar in both cases. The entire hydrogenation/etching process for both cases is analysed in detail, comparing with available theoretical and experimental evidences.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000401120800053 Publication Date 2017-03-26
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0008-6223 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.337 Times cited 2 Open Access OpenAccess
Notes U. K. gratefully acknowledges financial support from the Research Foundation – Flanders (FWO), Belgium (Grant No. 12M1315N). The work was carried out in part using the Turing HPC infrastructure of the CalcUA core facility of the Universiteit Antwerpen, a division of the Flemish Supercomputer Centre VSC, funded by the Hercules Foundation, the Flemish Government (department EWI) and the Universiteit Antwerpen. The authors also thank Prof. A. C. T. van Duin for sharing the ReaxFF code. Approved Most recent IF: 6.337
Call Number PLASMANT @ plasmant @ c:irua:141915 Serial 4531
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Author Khalilov, U.; Bogaerts, A.; Hussain, S.; Kovacevic, E.; Brault, P.; Boulmer-Leborgne, C.; Neyts, E.C.
Title Nanoscale mechanisms of CNT growth and etching in plasma environment Type A1 Journal article
Year 2017 Publication Journal of physics: D: applied physics Abbreviated Journal J Phys D Appl Phys
Volume 50 Issue 50 Pages 184001
Keywords (up) A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Plasma-enhanced chemical deposition (PECVD) of carbon nanotubes has already been shown to allow chirality control to some extent. In PECVD, however, etching may occur simultaneously with the growth, and the occurrence of intermediate processes further significantly complicates the growth process.

We here employ a computational approach with experimental support to study the plasma-based formation of Ni nanoclusters, Ni-catalyzed CNT growth and subsequent etching processes, in order to understand the underpinning nanoscale mechanisms. We find that hydrogen is the dominant factor in both the re-structuring of a Ni film and the subsequent appearance of Ni nanoclusters, as well as in the CNT nucleation and etching processes. The obtained results are compared with available theoretical and experimental studies and provide a deeper understanding of the occurring nanoscale mechanisms in plasma-assisted CNT nucleation and growth.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000398300900001 Publication Date 2017-04-03
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0022-3727 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.588 Times cited 6 Open Access OpenAccess
Notes UK gratefully acknowledges financial support from the Research Foundation – Flanders (FWO), Belgium (Grant No. 12M1315N). The work was carried out in part using the Turing HPC infrastructure of the CalcUA core facility of the Universiteit Antwerpen, a division of the Flemish Supercomputer Centre VSC, funded by the Hercules Foundation, the Flemish Government (department EWI) and the Universiteit Antwerpen. The authors also thank Prof A C T van Duin for sharing the ReaxFF code. Approved Most recent IF: 2.588
Call Number PLASMANT @ plasmant @ c:irua:141918 Serial 4533
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Author Khalilov, U.; Bogaerts, A.; Neyts, E.C.
Title Toward the Understanding of Selective Si Nano-Oxidation by Atomic Scale Simulations Type A1 Journal article
Year 2017 Publication Accounts of chemical research Abbreviated Journal Accounts Chem Res
Volume 50 Issue 50 Pages 796-804
Keywords (up) A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract The continuous miniaturization of nanodevices, such as transistors, solar cells, and optical fibers, requires the controlled synthesis of (ultra)thin gate oxides (<10 nm), including Si gate-oxide (SiO2) with high quality at the atomic scale. Traditional thermal growth of SiO2 on planar Si surfaces, however, does not allow one to obtain such ultrathin oxide due to either the high oxygen diffusivity at high temperature or the very low sticking ability of incident oxygen at low temperature. Two recent techniques, both operative at low (room) temperature, have been put forward to overcome these obstacles: (i) hyperthermal oxidation of planar Si surfaces and (ii) thermal or plasma-assisted oxidation of nonplanar Si surfaces, including Si nanowires (SiNWs). These nanooxidation processes are, however, often difficult to study experimentally, due to the key intermediate processes taking place on the nanosecond time scale.

In this Account, these Si nano-oxidation techniques are discussed from a computational point of view and compared to both hyperthermal and thermal oxidation experiments, as well as to well-known models of thermal oxidation, including the Deal−Grove, Cabrera−Mott, and Kao models and several alternative mechanisms. In our studies, we use reactive molecular dynamics (MD) and hybrid MD/Monte Carlo simulation techniques, applying the Reax force field. The incident energy of oxygen species is chosen in the range of 1−5 eV in hyperthermal oxidation of planar Si surfaces in order to prevent energy-induced damage. It turns out that hyperthermal growth allows for two growth modes, where the ultrathin oxide thickness depends on either (1) only the kinetic energy of the incident oxygen species at a growth temperature below Ttrans = 600 K, or (2) both the incident energy and the growth temperature at a growth temperature above Ttrans. These modes are specific to such ultrathin oxides, and are not observed in traditional thermal oxidation, nor theoretically considered by already existing models. In the case of thermal or plasma-assisted oxidation of small Si nanowires, on the other hand, the thickness of the ultrathin oxide is a function of the growth temperature and the nanowire diameter. Below Ttrans, which varies with the nanowire diameter, partially oxidized SiNW are formed, whereas complete oxidation to a SiO2 nanowire occurs only above Ttrans. In both nano-oxidation processes at lower temperature (T < Ttrans), final sandwich c-Si|SiOx|a-SiO2 structures are obtained due to a competition between overcoming the energy barrier to penetrate into Si subsurface layers and the compressive stress (∼2−3 GPa) at the Si crystal/oxide interface. The overall atomic-simulation results strongly indicate that the thickness of the intermediate SiOx (x < 2) region is very limited (∼0.5 nm) and constant irrespective of oxidation parameters. Thus, control over the ultrathin SiO2 thickness with good quality is indeed possible by accurately tuning the oxidant energy, oxidation temperature and surface curvature.

In general, we discuss and put in perspective these two oxidation mechanisms for obtaining controllable ultrathin gate-oxide films, offering a new route toward the fabrication of nanodevices via selective nano-oxidation.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000399859800016 Publication Date 2017-04-18
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0001-4842 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 20.268 Times cited 5 Open Access OpenAccess
Notes Fonds Wetenschappelijk Onderzoek, 12M1315N ; Approved Most recent IF: 20.268
Call Number PLASMANT @ plasmant @ c:irua:142638 Serial 4561
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Author Bruggeman, P.J.; Kushner, M.J.; Locke, B.R.; Gardeniers, J.G.E.; Graham, W.G.; Graves, D.B.; Hofman-Caris, R.C.H.M.; Maric, D.; Reid, J.P.; Ceriani, E.; Fernandez Rivas, D.; Foster, J.E.; Garrick, S.C.; Gorbanev, Y.; Hamaguchi, S.; Iza, F.; Jablonowski, H.; Klimova, E.; Kolb, J.; Krcma, F.; Lukes, P.; Machala, Z.; Marinov, I.; Mariotti, D.; Mededovic Thagard, S.; Minakata, D.; Neyts, E.C.; Pawlat, J.; Petrovic, Z.L.; Pflieger, R.; Reuter, S.; Schram, D.C.; Schröter, S.; Shiraiwa, M.; Tarabová, B.; Tsai, P.A.; Verlet, J.R.R.; von Woedtke, T.; Wilson, K.R.; Yasui, K.; Zvereva, G.
Title Plasma–liquid interactions: a review and roadmap Type A1 Journal article
Year 2016 Publication Plasma sources science and technology Abbreviated Journal Plasma Sources Sci T
Volume 25 Issue 5 Pages 053002
Keywords (up) A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Plasma–liquid interactions represent a growing interdisciplinary area of research involving plasma science, fluid dynamics, heat and mass transfer, photolysis, multiphase chemistry and aerosol science. This review provides an assessment of the state-of-the-art of this multidisciplinary area and identifies the key research challenges. The developments in diagnostics, modeling and further extensions of cross section and reaction rate databases that are necessary to address these challenges are discussed. The review focusses on nonequilibrium plasmas.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000384715400001 Publication Date 2016-09-30
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1361-6595 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.302 Times cited 460 Open Access
Notes This manuscript originated from discussions at the Lorentz Center Workshop ‘Gas/Plasma–Liquid Interface: Transport, Chemistry and Fundamental Data’ that took place at the Lorentz Center, Leiden University in the Netherlands from August 4, through August 8, 2014, and follow-up discussions since the workshop. All authors acknowledge the support of the Lorentz Center, the COST action TD1208 (Electrical Discharges with Liquids for Future Applications) and the Royal Dutch Academy of Sciences for their financial support. PJB, MJK, DBG and JEF acknowledge the support of the ‘Center on Control of Plasma Kinetics’ of the United States Department of Energy Office of Fusion Energy Science (DE-SC0001319). In addition, PJB and BRL acknowledge the support of the National Science Foundation (PHY 1500135 and CBET 1236225, respectively). In addition the enormous help of Mrs. Victoria Piorek (University of Minnesota) in the formatting of the final document including the references is gratefully acknowledged. Approved Most recent IF: 3.302
Call Number PLASMANT @ plasmant @ c:irua:144654 Serial 4628
Permanent link to this record
 
 
Author Shirazi, M.; Bogaerts, A.; Neyts, E.C.
Title A DFT study of H-dissolution into the bulk of a crystalline Ni(111) surface: a chemical identifier for the reaction kinetics Type A1 Journal article
Year 2017 Publication Physical chemistry, chemical physics Abbreviated Journal Phys Chem Chem Phys
Volume 19 Issue 19 Pages 19150-19158
Keywords (up) A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract In this study, we investigated the diffusion of H-atoms to the subsurface and their further diffusion into the bulk of a Ni(111) crystal by means of density functional theory calculations in the context of thermal and plasma-assisted catalysis. The H-atoms at the surface can originate from the dissociative adsorption of H2 or CH4 molecules, determining the surface H-coverage. When a threshold H-coverage is passed, corresponding to 1.00 ML for the crystalline Ni(111) surface, the surface-bound H-atoms start to diffuse to the subsurface. A similar threshold coverage is observed for the interstitial H-coverage. Once the interstitial sites are filled up with a coverage above 1.00 ML of H, dissolution of interstitial H-atoms to the layer below the interstitial sites will be initiated. Hence, by applying a high pressure or inducing a reactive plasma and high temperature, increasing the H-flux to the surface, a large amount of hydrogen can diffuse in a crystalline metal like Ni and can be absorbed. The formation of metal hydride may modify the entire reaction kinetics of the system. Equivalently, the H-atoms in the bulk can easily go back to the surface and release a large amount of heat. In a plasma process, H-atoms are formed in the plasma, and therefore the energy barrier for dissociative adsorption is dismissed, thus allowing achievement of the threshold coverage without applying a high pressure as in a thermal process. As a result, depending on the crystal plane and type of metal, a large number of H-atoms can be dissolved (absorbed) in the metal catalyst, explaining the high efficiency of plasma-assisted catalytic reactions. Here, the mechanism of H-dissolution is established as a chemical identifier for the investigation of the reaction kinetics of a chemical process.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000406334300034 Publication Date 2017-06-22
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1463-9076 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.123 Times cited 10 Open Access OpenAccess
Notes Financial support from the Reactive Atmospheric Plasma processIng – eDucation (RAPID) network, through the EU 7th Framework Programme (grant agreement no. 606889), is gratefully acknowledged. The calculations were performed 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. Approved Most recent IF: 4.123
Call Number PLASMANT @ plasmant @ c:irua:144794 Serial 4633
Permanent link to this record
 
 
Author Neyts, E.C.; Bal, K.M.
Title Effect of electric fields on plasma catalytic hydrocarbon oxidation from atomistic simulations Type A1 Journal article
Year 2017 Publication Plasma processes and polymers Abbreviated Journal Plasma Process Polym
Volume 14 Issue 6 Pages e1600158
Keywords (up) A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract The catalytic oxidative dehydrogenation of hydrocarbons is an industrially important process, in which selectivity is a key issue. We here investigate the conversion of methanol to formaldehyde on a vanadia surface employing long timescale simulations, reaching a time scale of seconds. In particular, we compare the thermal process to the case where an additional external electric field is applied, as would be the case in a direct plasma-catalysis setup. We find that the electric field influences the retention time of the molecules at the catalyst surface. These simulations provide an atomic scale insight in the thermal catalytic oxidative dehydrogenation process, and in how an external electric field may affect this process.
Address
Corporate Author Thesis
Publisher Place of Publication Weinheim Editor
Language Wos 000403699900013 Publication Date 2016-11-08
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1612-8850 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.846 Times cited 2 Open Access Not_Open_Access
Notes Approved Most recent IF: 2.846
Call Number UA @ lucian @ c:irua:144210 Serial 4647
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Author Aussems, D.U.B.; Bal, K. M.; Morgan, T.W.; van de Sanden, M.C.M.; Neyts, E.C.
Title Atomistic simulations of graphite etching at realistic time scales Type A1 Journal article
Year 2017 Publication Chemical science Abbreviated Journal Chem Sci
Volume 8 Issue 10 Pages 7160-7168
Keywords (up) A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Hydrogen–graphite interactions are relevant to a wide variety of applications, ranging from astrophysics to fusion devices and nano-electronics. In order to shed light on these interactions, atomistic simulation using Molecular Dynamics (MD) has been shown to be an invaluable tool. It suffers, however, from severe timescale

limitations. In this work we apply the recently developed Collective Variable-Driven Hyperdynamics (CVHD) method to hydrogen etching of graphite for varying inter-impact times up to a realistic value of 1 ms, which corresponds to a flux of 1020 m2 s1. The results show that the erosion yield, hydrogen surface coverage and species distribution are significantly affected by the time between impacts. This can be explained by the higher probability of C–C bond breaking due to the prolonged exposure to thermal stress and the subsequent transition from ion- to thermal-induced etching. This latter regime of thermal-induced etching – chemical erosion – is here accessed for the first time using atomistic simulations. In conclusion, this study demonstrates that accounting for long time-scales significantly affects ion bombardment simulations and should not be neglected in a wide range of conditions, in contrast to what is typically assumed.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000411730500055 Publication Date 2017-08-24
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2041-6520 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 8.668 Times cited 3 Open Access OpenAccess
Notes DIFFER is part of the Netherlands Organisation for Scientic Research (NWO). K. M. B. is funded as a PhD fellow (aspirant) of the FWO-Flanders (Fund for Scientic Research-Flanders), Grant 11V8915N. The computational resources and services used in this work were provided by the VSC (Flemish Supercomputer Center), funded by the Research Foundation – Flanders (FWO) and the Flemish Government – department EWI. Approved Most recent IF: 8.668
Call Number PLASMANT @ plasmant @c:irua:145519 Serial 4707
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Author Bal, K.M.; Huygh, S.; Bogaerts, A.; Neyts, E.C.
Title Effect of plasma-induced surface charging on catalytic processes: application to CO2activation Type A1 Journal article
Year 2018 Publication Plasma sources science and technology Abbreviated Journal Plasma Sources Sci T
Volume 27 Issue 2 Pages 024001
Keywords (up) A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Understanding the nature and effect of the multitude of plasma–surface interactions in plasma catalysis is a crucial requirement for further process development and improvement. A particularly intriguing and rather unique property of a plasma-catalytic setup is the ability of the plasma to modify the electronic structure, and hence chemical properties, of the catalyst through charging, i.e. the absorption of excess electrons. In this work, we develop a quantum chemical model based on density functional theory to study excess negative surface charges in a heterogeneous catalyst exposed to a plasma. This method is specifically applied to investigate plasma-catalytic CO2 activation on supported M/Al2O3 (M=Ti, Ni, Cu) single atom catalysts. We find that (1) the presence of a negative surface charge dramatically improves the reductive power of the catalyst, strongly promoting the splitting of CO2 to CO and oxygen, and (2) the relative activity of the investigated transition metals is also changed upon charging, suggesting that controlled surface charging is a powerful additional parameter to tune catalyst activity and selectivity. These results strongly point to plasma-induced surface charging of the catalyst as an important factor contributing to the plasma-catalyst synergistic effects frequently reported for plasma catalysis.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000424520100001 Publication Date 2018-02-07
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1361-6595 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.302 Times cited 19 Open Access OpenAccess
Notes KMB is funded as PhD fellow (aspirant) of the FWO-Flanders (Research Foundation—Flanders), Grant 11V8915N. The computational resources and services used in this work were provided by the VSC (Flemish Supercomputer Center), funded by the FWO and the Flemish Government— department EWI. Approved Most recent IF: 3.302
Call Number PLASMANT @ plasmant @c:irua:149285 Serial 4813
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Author Razzokov, J.; Yusupov, M.; Vanuytsel, S.; Neyts, E.C.; Bogaerts, A.
Title Phosphatidylserine flip-flop induced by oxidation of the plasma membrane: a better insight by atomic scale modeling Type A1 Journal article
Year 2017 Publication Plasma processes and polymers Abbreviated Journal Plasma Process Polym
Volume 14 Issue 10 Pages 1700013
Keywords (up) A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract We perform molecular dynamics simulations to study the flip-flop motion of phosphatidylserine (PS) across the plasma membrane upon increasing oxidation degree of the membrane. Our computational results show that an increase of the oxidation degree in the lipids leads to a decrease of the free energy barrier for translocation of PS through the membrane. In other words, oxidation of the lipids facilitates PS flip-flop motion across the membrane, because in native phospholipid bilayers this is only a “rare event” due to the high energy barriers for the translocation of PS. The present study provides an atomic-scale insight into the mechanisms of the PS flip-flop upon oxidation of lipids, as produced for example by cold atmospheric plasma, in living cells.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000413045800010 Publication Date 2017-04-05
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1612-8850 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.846 Times cited 9 Open Access Not_Open_Access
Notes Fonds Wetenschappelijk Onderzoek, 1200216N ; Approved Most recent IF: 2.846
Call Number PLASMANT @ plasmant @c:irua:149567 Serial 4910
Permanent link to this record
 
 
Author Bal, K.M.; Neyts, E.C.
Title Modelling molecular adsorption on charged or polarized surfaces: a critical flaw in common approaches Type A1 Journal article
Year 2018 Publication Physical chemistry, chemical physics Abbreviated Journal Phys Chem Chem Phys
Volume 20 Issue 13 Pages 8456-8459
Keywords (up) A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract A number of recent computational material design studies based on density functional theory (DFT) calculations have put forward a new class of materials with electrically switchable chemical characteristics that can be exploited in the development of tunable gas storage and electrocatalytic applications. We find systematic flaws in almost every computational study of gas adsorption on polarized or charged surfaces, stemming from an improper and unreproducible treatment of periodicity, leading to very large errors of up to 3 eV in some cases. Two simple corrective procedures that lead to consistent results are proposed, constituting a crucial course correction to the research in the field.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000428779700007 Publication Date 2018-03-12
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1463-9076 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.123 Times cited 8 Open Access OpenAccess
Notes K. M. B. is funded as PhD fellow (aspirant) of the FWO-Flanders (Research Foundation – Flanders), Grant 11V8915N. The computational resources and services used in this work were provided by the VSC (Flemish Supercomputer Center), funded by the FWO and the Flemish Government – department EWI. Approved Most recent IF: 4.123
Call Number PLASMANT @ plasmant @c:irua:150357 Serial 4916
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Author Heyne, M.H.; de Marneffe, J.-F.; Nuytten, T.; Meersschaut, J.; Conard, T.; Caymax, M.; Radu, I.; Delabie, A.; Neyts, E.C.; De Gendt, S.
Title The conversion mechanism of amorphous silicon to stoichiometric WS2 Type A1 Journal article
Year 2018 Publication Journal of materials chemistry C : materials for optical and electronic devices Abbreviated Journal J Mater Chem C
Volume 6 Issue 15 Pages 4122-4130
Keywords (up) A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract The deposition of ultra-thin tungsten films and their related 2D chalcogen compounds on large area dielectric substrates by gas phase reactions is challenging. The lack of nucleation sites complicates the adsorption of W-related precursors and subsequent sulfurization usually requires high temperatures. We propose here a technique in which a thin solid amorphous silicon film is used as reductant for the gas phase precursor WF6 leading to the conversion to metallic W. The selectivity of the W conversion towards the underlying dielectric surfaces is demonstrated. The role of the Si surface preparation, the conversion temperature, and Si thickness on the formation process is investigated. Further, the in situ conversion of the metallic tungsten into thin stoichiometric WS2 is achieved by a cyclic approach based on WF6 and H2S pulses at the moderate temperature of 450 1C, which is much lower than usual oxide sulfurization processes.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000430538000036 Publication Date 2018-03-20
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2050-7526 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 5.256 Times cited 4 Open Access OpenAccess
Notes This work was supported throughout a strategic fundamental research grant for M. H. by the agency Flanders innovation & entrepreneurship (VLAIO). Approved Most recent IF: 5.256
Call Number PLASMANT @ plasmant @c:irua:150968 Serial 4921
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Author Neyts, E.C.
Title Atomistic simulations of plasma catalytic processes Type A1 Journal article
Year 2018 Publication Frontiers of Chemical Science and Engineering Abbreviated Journal Front Chem Sci Eng
Volume 12 Issue 1 Pages 145-154
Keywords (up) A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract There is currently a growing interest in the realisation and optimization of hybrid plasma/catalyst systems for a multitude of applications, ranging from nanotechnology to environmental chemistry. In spite of this interest, there is, however, a lack in fundamental understanding of the underlying processes in such systems. While a lot of experimental research is already being carried out to gain this understanding, only recently the first simulations have appeared in the literature. In this contribution, an overview is presented on atomic scale simulations of plasma catalytic processes as carried out in our group. In particular, this contribution focusses on plasma-assisted catalyzed carbon nanostructure growth, and plasma catalysis for greenhouse gas conversion. Attention is paid to what can routinely be done, and where challenges persist.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000425156500017 Publication Date 2017-09-30
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2095-0179 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.712 Times cited 5 Open Access Not_Open_Access
Notes Approved Most recent IF: 1.712
Call Number UA @ lucian @ c:irua:149233 Serial 4927
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Author Nematollahi, P.; Neyts, E.C.
Title A comparative DFT study on CO oxidation reaction over Si-doped BC2N nanosheet and nanotube Type A1 Journal article
Year 2018 Publication Applied surface science Abbreviated Journal Appl Surf Sci
Volume 439 Issue 439 Pages 934-945
Keywords (up) A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract In this study, we performed density functional theory (DFT) calculations to investigate different reaction mechanisms of CO oxidation catalyzed by the Si atom embedded defective BC2N nanostructures as well as the analysis of the structural and electronic properties. The structures of all the complexes are optimized and characterized by frequency calculations at the M062X/6-31G* computational level. Also, The electronic structures and thermodynamic parameters of adsorbed CO and O-2 molecules over Si-doped BC2N nanostructures are examined in detail. Moreover, to investigate the curvature effect on the CO oxidation reaction, all the adsorption and CO oxidation reactions on a finite-sized armchair (6,6) Si-BC2NNT are also studied. Our results indicate that there can be two possible pathways for the CO oxidation with O-2 molecule: O-2(g) + CO(g) -> O-2(ads) + CO(ads) -> CO2(g) + O-(ads) and O-(ads) + CO(g) -> CO2(g). The first reaction proceeds via the Langmuir-Hinshelwood (LH) mechanism while the second goes through the Eley-Rideal (ER) mechanism. On the other hand, by increasing the tube diameter, the energy barrier increases due to the strong adsorption energy of the O-2 molecule which is related to its dissociation over the tube surface. Our calculations indicate that the two step energy barrier of the oxidation reaction over Si-BC2NNS is less than that over the Si-BC2NNT. Hence, Si-BC2NNS may serve as an efficient and highly activated substrate to CO oxidation rather than (4,4) Si-BC2NNT. (C) 2018 Elsevier B.V. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000427457100112 Publication Date 2018-01-08
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0169-4332 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.387 Times cited 8 Open Access Not_Open_Access
Notes Approved Most recent IF: 3.387
Call Number UA @ lucian @ c:irua:150745 Serial 4960
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