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Author Surmenev, R.A.; Grubova, I.Y.; Neyts, E.; Teresov, A.D.; Koval, N.N.; Epple, M.; Tyurin, A.I.; Pichugin, V.F.; Chaikina, M.V.; Surmeneva, M.A.
Title Ab initio calculations and a scratch test study of RF-magnetron sputter deposited hydroxyapatite and silicon-containing hydroxyapatite coatings Type A1 Journal article
Year 2020 Publication Surfaces and interfaces Abbreviated Journal
Volume 21 Issue Pages
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract A crucial property for implants is their biocompatibility. To ensure biocompatibility, thin coatings of hydroxyapatite (HA) are deposited on the actual implant. In this study, we investigate the effects of the addition of silicate anions to the structure of hydroxyapatite coatings on their adhesion strength via a scratch test and ab initio calculations. We find that both the grain size and adhesion strength decrease with the increase in the silicon content in the HA coating (SiHA). The increase in the silicon content to 1.2 % in the HA coating leads to a decrease in the average crystallite size from 28 to 21 nm, and in the case of 4.6 %, it leads to the formation of an amorphous or nanocrystalline film. The decreases in the grain and crystallite sizes lead to peeling and destruction of the coating from the titanium substrate at lower loads. Further, our ab initio simulations demonstrate an increased number of molecular bonds at the amorphous SiHA-TiO2 interface. However, the experimental results revealed that the structure and grain size have more pronounced effects on the adhesion strength of the coatings. In conclusion, based on the results of the ab initio simulations and the experimental results, we suggest that the presence of Si in the form of silicate ions in the HA coating has a significant impact on the structure, grain size, and number of molecular bonds at the interface and on the adhesion strength of the SiHA coating to the titanium substrate.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000697616300009 Publication Date 2020-10-02
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2468-0230 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.2 Times cited Open Access
Notes Approved (up) Most recent IF: 6.2; 2020 IF: NA
Call Number UA @ admin @ c:irua:181685 Serial 7400
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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 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 (up) Most recent IF: 6.337
Call Number PLASMANT @ plasmant @ c:irua:141915 Serial 4531
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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 Mechanisms of elementary hydrogen ion-surface interactions during multilayer graphene etching at high surface temperature as a function of flux Type A1 Journal article
Year 2018 Publication Carbon Abbreviated Journal Carbon
Volume 137 Issue Pages 527-532
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract In order to optimize the plasma-synthesis and modification process of carbon nanomaterials for applications such as nanoelectronics and energy storage, a deeper understanding of fundamental hydrogengraphite/graphene interactions is required. Atomistic simulations by Molecular Dynamics have proven to be indispensable to illuminate these phenomena. However, severe time-scale limitations restrict them to very fast processes such as reflection, while slow thermal processes such as surface diffusion and molecular desorption are commonly inaccessible. In this work, we could however reach these thermal processes for the first time at time-scales and surface temperatures (1000 K) similar to high-flux plasma exposure experiments during the simulation of multilayer graphene etching by 5 eV H ions. This was achieved by applying the Collective Variable-Driven Hyperdynamics biasing technique, which extended the inter-impact time over a range of six orders of magnitude, down to a more realistic ion-flux of 1023m2s1. The results show that this not only causes a strong shift from predominant ion-to thermally induced interactions, but also significantly affects the hydrogen uptake and surface evolution. This study thus elucidates H ion-graphite/graphene interaction mechanisms and stresses the importance of including long time-scales in atomistic simulations at high surface temperatures to understand the dynamics of the ion-surface system.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000440661700056 Publication Date 2018-05-24
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 4 Open Access Not_Open_Access: Available from 25.05.2020
Notes DIFFER is part of the Netherlands Organisation for Scientific Research (NWO). K.M.B. is funded as PhD fellow (aspirant) of the FWO-Flanders (Fund for Scientific Research-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 e department EWI. Approved (up) Most recent IF: 6.337
Call Number PLASMANT @ plasmant @c:irua:152172 Serial 4993
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Author Khalilov, U.; Vets, C.; Neyts, E.C.
Title Catalyzed growth of encapsulated carbyne Type A1 Journal article
Year 2019 Publication Carbon Abbreviated Journal Carbon
Volume 153 Issue Pages 1-5
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Carbyne is a novel material of current interest in nanotechnology. As is typically the case for nanomaterials, the growth process determines the resulting properties. While endohedral carbyne has been successfully synthesized, its catalyst and feedstock-dependent growth mechanism is still elusive. We here study the nucleation and growth mechanism of different carbon chains in a Ni-containing double walled carbon nanotube using classical molecular dynamics simulations and first-principles calculations. We find that the understanding the competitive role of the metal catalyst and the hydrocarbon is important to control the growth of 1-dimensional carbon chains, including Ni or H-terminated carbyne. Also, we find that the electronic property of the Ni-terminated carbyne can be tuned by steering the H concentration along the chain. These results suggest catalyst-containing carbon nanotubes as a possible synthesis route for carbyne formation.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000485054200001 Publication Date 2019-07-01
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 Open Access Not_Open_Access
Notes Fund of Scientific Research Flanders (FWO), Belgium, 12M1318N 1S22516N ; Flemish Supercomputer Centre VSC; Hercules Foundation; Flemish Government; University of Antwerp; The authors gratefully acknowledge the financial support from the Fund of Scientific Research Flanders (FWO), Belgium, Grant numbers 12M1318N and 1S22516N. 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 University of Antwerp. Approved (up) Most recent IF: 6.337
Call Number PLASMANT @ plasmant @c:irua:160695 Serial 5187
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Author Khalilov, U.; Neyts, E.C.
Title Mechanisms of selective nanocarbon synthesis inside carbon nanotubes Type A1 Journal article
Year 2021 Publication Carbon Abbreviated Journal Carbon
Volume 171 Issue Pages 72-78
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract The possibility of confinement effects inside a carbon nanotube provides new application opportunities, e.g., growth of novel carbon nanostructures. However, the understanding the precise role of catalystfeedstock in the nanostructure synthesis is still elusive. In our simulation-based study, we investigate the Ni-catalyzed growth mechanism of encapsulated carbon nanostructures, viz. double-wall carbon nanotube and graphene nanoribbon, from carbon and hydrocarbon growth precursors, respectively. Specifically, we find that the tube and ribbon growth is determined by a catalyst-vs-feedstock competition effect. We compare our results, i.e., growth mechanism and structure morphology with all available theoretical and experimental data. Our calculations show that all encapsulated nanostructures contain metal (catalyst) atoms and such structures are less stable than their pure counterparts. Therefore, we study the purification mechanism of these structures. In general, this study opens a possible route to the controllable synthesis of tubular and planar carbon nanostructures for today’s nanotechnology.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000598371500009 Publication Date 2020-09-02
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0008-6223 ISBN Additional Links UA library record; WoS full record
Impact Factor 6.337 Times cited Open Access OpenAccess
Notes Fund of Scientific Research Flanders, 12M1318N ; Universiteit Antwerpen; Flemish Supercomputer Centre; Hercules Foundation; Flemish Government; The authors gratefully acknowledge the financial support from the Fund of Scientific Research Flanders (FWO), Belgium, Grant number 12M1318N. The work was carried out in part using the Turing HPC infrastructure of the CalcUA core facility of the Universiteit Antwerpen (UA), a division of the Flemish Supercomputer Centre (VSC), funded by the Hercules Foundation, the Flemish Government (department EWI) and the UA, Belgium. Approved (up) Most recent IF: 6.337
Call Number PLASMANT @ plasmant @c:irua:172459 Serial 6414
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Author Fukuhara, S.; Bal, K.M.; Neyts, E.C.; Shibuta, Y.
Title Entropic and enthalpic factors determining the thermodynamics and kinetics of carbon segregation from transition metal nanoparticles Type A1 Journal article
Year 2021 Publication Carbon Abbreviated Journal Carbon
Volume 171 Issue Pages 806-813
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract The free energy surface (FES) for carbon segregation from nickel nanoparticles is obtained from advanced molecular dynamics simulations. A suitable reaction coordinate is developed that can distinguish dissolved carbon atoms from segregated dimers, chains and junctions on the nanoparticle surface. Because of the typically long segregation time scale (up to ms), metadynamics simulations along the developed reaction coordinate are used to construct FES over a wide range of temperatures and carbon concentrations. The FES revealed the relative stability of different stages in the segregation process, and free energy barriers and rates of the individual steps could then be calculated and decomposed into enthalpic and entropic contributions. As the carbon concentration in the nickel nanoparticle increases, segregated carbon becomes more stable in terms of both enthalpy and entropy. The activation free energy of the reaction also decreases with the increase of carbon concentration, which can be mainly attributed to entropic effects. These insights and the methodology developed to obtain them improve our understanding of carbon segregation process across materials science in general, and the nucleation and growth of carbon nanotube in particular.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000598371500084 Publication Date 2020-09-25
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 Open Access OpenAccess
Notes Scientific Research, 19H02415 ; JSPS, 18J22727 ; Japan Society for the Promotion of Science; JSPS; JSPS; FWO; Research Foundation; Flanders, 12ZI420N ; This work was supported by Grant-in-Aid for Scientific Research (B) (No.19H02415) and Grant-in-Aid for JSPS Research Fellow (No.18J22727) from Japan Society for the Promotion of Science (JSPS), Japan. S.F. was supported by JSPS through the Program for 812 Approved (up) Most recent IF: 6.337
Call Number PLASMANT @ plasmant @c:irua:172452 Serial 6421
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Author Neyts, E.C.; Bogaerts, A.
Title Formation of endohedral Ni@C60 and exohedral NiC60 metallofullerene complexes by simulated ion implantation Type A1 Journal article
Year 2009 Publication Carbon Abbreviated Journal Carbon
Volume 47 Issue 4 Pages 1028-1033
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract The interaction of thermal and hyperthermal Ni ions with gas-phase C60 fullerene was investigated at two temperatures with classical molecular dynamics simulations using a recently developed interatomic many-body potential. The interaction between Ni and C60 is characterized in terms of the NiC60 binding sites, complex formation, and the collision and temperature induced deformation of the C60 cage structure. The simulations show how ion implantation theoretically allows the synthesis of both endohedral Ni@C60 and exohedral NiC60 metallofullerene complexes.
Address
Corporate Author Thesis
Publisher Place of Publication Oxford Editor
Language Wos 000264252900012 Publication Date 2008-12-25
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 15 Open Access
Notes Approved (up) Most recent IF: 6.337; 2009 IF: 4.504
Call Number UA @ lucian @ c:irua:76434 Serial 1260
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Author Neyts, E.; Maeyens, A.; Pourtois, G.; Bogaerts, A.
Title A density-functional theory simulation of the formation of Ni-doped fullerenes by ion implantation Type A1 Journal article
Year 2011 Publication Carbon Abbreviated Journal Carbon
Volume 49 Issue 3 Pages 1013-1017
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Using self-consistent KohnSham density-functional theory molecular dynamics simulations, we demonstrate the theoretical possibility to synthesize NiC60, the incarfullerene Ni@C60 and the heterofullerene C59Ni in an ion implantation setup. The corresponding formation mechanisms of all three complexes are elucidated as a function of the ion implantation energy and impact location, suggesting possible routes for selectively synthesizing these complexes.
Address
Corporate Author Thesis
Publisher Place of Publication Oxford Editor
Language Wos 000286683500032 Publication Date 2010-11-14
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 13 Open Access
Notes Approved (up) Most recent IF: 6.337; 2011 IF: 5.378
Call Number UA @ lucian @ c:irua:85139 Serial 639
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Author Shariat, M.; Hosseini, S.I.; Shokri, B.; Neyts, E.C.
Title Plasma enhanced growth of single walled carbon nanotubes at low temperature : a reactive molecular dynamics simulation Type A1 Journal article
Year 2013 Publication Carbon Abbreviated Journal Carbon
Volume 65 Issue Pages 269-276
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Low-temperature growth of carbon nanotubes (CNTs) has been claimed to provide a route towards chiral-selective growth, enabling a host of applications. In this contribution, we employ reactive molecular dynamics simulations to demonstrate how plasma-based deposition allows such low-temperature growth. We first show how ion bombardment during the growth affects the carbon dissolution and precipitation process. We then continue to demonstrate how a narrow ion energy window allows CNT growth at 500 K. Finally, we also show how CNTs in contrast cannot be grown in thermal CVD at this low temperature, but only at high temperature, in agreement with experimental data. (C) 2013 Elsevier Ltd. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Oxford Editor
Language Wos 000326773200031 Publication Date 2013-08-23
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 21 Open Access
Notes Approved (up) Most recent IF: 6.337; 2013 IF: 6.160
Call Number UA @ lucian @ c:irua:112697 Serial 2635
Permanent link to this record
 

 
Author Neyts, E.C.; Bogaerts, A.
Title Ion irradiation for improved graphene network formation in carbon nanotube growth Type A1 Journal article
Year 2014 Publication Carbon Abbreviated Journal Carbon
Volume 77 Issue Pages 790-795
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Ion irradiation of carbon nanotubes very often leads to defect formation. However, we have recently shown that Ar ion irradiation in a limited energy window of 1025 eV may enhance the initial cap nucleation process, when the carbon network is in contact with the metal nanocatalyst. Here, we employ reactive molecular dynamics simulations to demonstrate that ion irradiation in a higher energy window of 1035 eV may also heal network defects after the nucleation stage through a non-metal-mediated mechanism, when the carbon network is no longer in contact with the metal nanocatalyst. The results demonstrate the possibility of beneficially utilizing ions in e.g. plasma-enhanced chemical vapour deposition of carbon nanotubes.
Address
Corporate Author Thesis
Publisher Place of Publication Oxford Editor
Language Wos 000340689400083 Publication Date 2014-06-11
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 7 Open Access
Notes Approved (up) Most recent IF: 6.337; 2014 IF: 6.196
Call Number UA @ lucian @ c:irua:118062 Serial 1745
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Author Faraji, F.; Neek-Amal, M.; Neyts, E.C.; Peeters, F.M.
Title Indentation of graphene nano-bubbles Type A1 Journal article
Year 2022 Publication Nanoscale Abbreviated Journal Nanoscale
Volume 14 Issue 15 Pages 5876-5883
Keywords A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Molecular dynamics simulations are used to investigate the effect of an AFM tip when indenting graphene nano bubbles filled by a noble gas (i.e. He, Ne and Ar) up to the breaking point. The failure points resemble those of viral shells as described by the Foppl-von Karman (FvK) dimensionless number defined in the context of elasticity theory of thin shells. At room temperature, He gas inside the bubbles is found to be in the liquid state while Ne and Ar atoms are in the solid state although the pressure inside the nano bubble is below the melting pressure of the bulk. The trapped gases are under higher hydrostatic pressure at low temperatures than at room temperature.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000776763000001 Publication Date 2022-03-30
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2040-3364; 2040-3372 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.7 Times cited Open Access OpenAccess
Notes Approved (up) Most recent IF: 6.7
Call Number UA @ admin @ c:irua:187924 Serial 7171
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Author Heyne, M.H.; Marinov, D.; Braithwaite, N.; Goodyear, A.; de Marneffe, J.-F.; Cooke, M.; Radu, I.; Neyts, E.C.; De Gendt, S.
Title A route towards the fabrication of 2D heterostructures using atomic layer etching combined with selective conversion Type A1 Journal article
Year 2019 Publication 2D materials Abbreviated Journal 2D Mater
Volume 6 Issue 3 Pages 035030
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Heterostructures of low-dimensional semiconducting materials, such as transition metal dichalcogenides (MX2), are promising building blocks for future electronic and optoelectronic devices. The patterning of one MX2 material on top of another one is challenging due to their structural similarity. This prevents an intrinsic etch stop when conventional anisotropic dry etching processes are used. An alternative approach consist in a two-step process, where a sacrificial silicon layer is pre-patterned with a low damage plasma process, stopping on the underlying MoS2 film. The pre-patterned layer is used as sacrificial template for the formation of the top WS2 film. This study describes the optimization of a cyclic Ar/Cl-2 atomic layer etch process applied to etch silicon on top of MoS2, with minimal damage, followed by a selective conversion of the patterned Si into WS2. The impact of the Si atomic layer etch towards the MoS2 is evaluated: in the ion energy range used for this study, MoS2 removal occurs in the over-etch step over 1-2 layers, leading to the appearance of MoOx but without significant lattice distortions to the remaining layers. The combination of Si atomic layer etch, on top of MoS2, and subsequent Si-to-WS2 selective conversion, allows to create a WS2/MoS2 heterostructure, with clear Raman signals and horizontal lattice alignment. These results demonstrate a scalable, transfer free method to achieve horizontally individually patterned heterostacks and open the route towards wafer-level processing of 2D materials.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000468335500004 Publication Date 2019-04-23
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2053-1583 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.937 Times cited Open Access Not_Open_Access
Notes Approved (up) Most recent IF: 6.937
Call Number UA @ admin @ c:irua:160229 Serial 5266
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Author Faraji, F.; Neyts, E.C.; Milošević, M.V.; Peeters, F.M.
Title Comment on “Misinterpretation of the Shuttleworth equation” Type A1 Journal Article
Year 2024 Publication Scripta Materialia Abbreviated Journal Scripta Materialia
Volume 250 Issue Pages 116186
Keywords A1 Journal Article; CMT
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos Publication Date 2024-05-24
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1359-6462 ISBN Additional Links
Impact Factor 6 Times cited Open Access
Notes Research Foundation Flanders; Approved (up) Most recent IF: 6; 2024 IF: 3.747
Call Number UA @ lucian @ CMT Serial 9116
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Author Khalilov, U.; Uljayev, U.; Mehmonov, K.; Nematollahi, P.; Yusupov, M.; Neyts, E.C.; Neyts, E.C.
Title Can endohedral transition metals enhance hydrogen storage in carbon nanotubes? Type A1 Journal article
Year 2024 Publication International journal of hydrogen energy Abbreviated Journal
Volume 55 Issue Pages 640-610
Keywords A1 Journal article; Engineering sciences. Technology; Modelling and Simulation in Chemistry (MOSAIC); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract The safe and efficient use of hydrogen energy, which is in high demand worldwide today, requires efficient hydrogen storage. Despite significant advances in hydrogen storage using carbon-based nanomaterials, including carbon nanotubes (CNTs), efforts to substantially increase the storage capacity remain less effective. In this work, we demonstrate the effect of endohedral transition metal atoms on the hydrogen storage capacity of CNTs using reactive molecular dynamics simulations. We find that an increase in the volume fraction of endohedral nickel atoms leads to an increase in the concentration of physisorbed hydrogen molecules around single-walled CNTs (SWNTs) by approximately 1.6 times compared to pure SWNTs. The obtained results provide insight into the underlying mechanisms of how endohedral transition metal atoms enhance the hydrogen storage ability of SWNTs under nearly ambient conditions.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 001142427400001 Publication Date 2023-11-24
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0360-3199 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 7.2 Times cited Open Access Not_Open_Access
Notes Approved (up) Most recent IF: 7.2; 2024 IF: 3.582
Call Number UA @ admin @ c:irua:202315 Serial 9006
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Author Khalilov, U.; Bogaerts, A.; Xu, B.; Kato, T.; Kaneko, T.; Neyts, E.C.
Title How the alignment of adsorbed ortho H pairs determines the onset of selective carbon nanotube etching Type A1 Journal article
Year 2017 Publication Nanoscale Abbreviated Journal Nanoscale
Volume 9 Issue 9 Pages 1653-1661
Keywords A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Unlocking the enormous technological potential of carbon nanotubes strongly depends on our ability to specifically produce metallic or semiconducting tubes. While selective etching of both has already been demonstrated, the underlying reasons, however, remain elusive as yet. We here present computational and experimental evidence on the operative mechanisms at the atomic scale. We demonstrate that during the adsorption of H atoms and their coalescence, the adsorbed ortho hydrogen pairs on single-walled carbon nanotubes induce higher shear stresses than axial stresses, leading to the elongation of HC–CH bonds as a function of their alignment with the tube chirality vector, which we denote as the γ-angle. As a result, the C–C cleavage occurs more rapidly in nanotubes containing ortho H-pairs with a small γ-angle. This phenomenon can explain the selective etching of small-diameter semiconductor nanotubes with a similar curvature. Both theoretical and experimental results strongly indicate the important role of the γ-angle in the selective etching mechanisms of carbon nanotubes, in addition to the nanotube curvature and metallicity effects and lead us to clearly understand the onset of selective synthesis/removal of CNT-based materials.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000395422800036 Publication Date 2016-12-19
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2040-3364 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 7.367 Times cited 6 Open Access OpenAccess
Notes U. K. gratefully acknowledges financial support from the Fund of Scientific Research Flanders (FWO), Belgium (Grant No. 12M1315N). This work was also supported in part by Grant-in- Aid for Young Scientists A (Grant No. 25706028), Grant-in-Aid for Scientific Research on Innovative Areas (Grant No. 26107502) from JSPS KAKENHI. This work was carried out in part using the Turing HPC infrastructure at the CalcUA core facility of the Universiteit Antwerpen (UA), a division of the Flemish Supercomputer Center VSC, funded by the Hercules Foundation, the Flemish Government (department EWI) and the UA. The authors also thank Prof. A. C. T. van Duin for sharing the ReaxFF code and J. Razzokov for his assistance to perform the DFT calculations. Approved (up) Most recent IF: 7.367
Call Number PLASMANT @ plasmant @ c:irua:140091 Serial 4417
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Author Elliott, J.A.; Shibuta, Y.; Amara, H.; Bichara, C.; Neyts, E.C.
Title Atomistic modelling of CVD synthesis of carbon nanotubes and graphene Type A1 Journal article
Year 2013 Publication Nanoscale Abbreviated Journal Nanoscale
Volume 5 Issue 15 Pages 6662-6676
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract We discuss the synthesis of carbon nanotubes (CNTs) and graphene by catalytic chemical vapour deposition (CCVD) and plasma-enhanced CVD (PECVD), summarising the state-of-the-art understanding of mechanisms controlling their growth rate, chiral angle, number of layers (walls), diameter, length and quality (defects), before presenting a new model for 2D nucleation of a graphene sheet from amorphous carbon on a nickel surface. Although many groups have modelled this process using a variety of techniques, we ask whether there are any complementary ideas emerging from the different proposed growth mechanisms, and whether different modelling techniques can give the same answers for a given mechanism. Subsequently, by comparing the results of tight-binding, semi-empirical molecular orbital theory and reactive bond order force field calculations, we demonstrate that graphene on crystalline Ni(111) is thermodynamically stable with respect to the corresponding amorphous metal and carbon structures. Finally, we show in principle how a complementary heterogeneous nucleation step may play a key role in the transformation from amorphous carbon to graphene on the metal surface. We conclude that achieving the conditions under which this complementary crystallisation process can occur may be a promising method to gain better control over the growth processes of both graphene from flat metal surfaces and CNTs from catalyst nanoparticles.
Address
Corporate Author Thesis
Publisher Place of Publication Cambridge Editor
Language Wos 000321675600003 Publication Date 2013-06-06
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2040-3364;2040-3372; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 7.367 Times cited 52 Open Access
Notes Approved (up) Most recent IF: 7.367; 2013 IF: 6.739
Call Number UA @ lucian @ c:irua:109231 Serial 200
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Author Neyts, E.C.; van Duin, A.C.T.; Bogaerts, A.
Title Formation of single layer graphene on nickel under far-from-equilibrium high flux conditions Type A1 Journal article
Year 2013 Publication Nanoscale Abbreviated Journal Nanoscale
Volume 5 Issue 16 Pages 7250-7255
Keywords A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract We investigate the theoretical possibility of single layer graphene formation on a nickel surface at different substrate temperatures under far-from-equilibrium high precursor flux conditions, employing state-of-the-art hybrid reactive molecular dynamics/uniform acceptance force bias Monte Carlo simulations. It is predicted that under these conditions, the formation of a single layer graphene-like film may proceed through a combined depositionsegregation mechanism on a nickel substrate, rather than by pure surface segregation as is typically observed for metals with high carbon solubility. At 900 K and above, nearly continuous graphene layers are obtained. These simulations suggest that single layer graphene deposition is theoretically possible on Ni under high flux conditions.
Address
Corporate Author Thesis
Publisher Place of Publication Cambridge Editor
Language Wos 000322315600019 Publication Date 2013-04-26
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2040-3364;2040-3372; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 7.367 Times cited 25 Open Access
Notes Approved (up) Most recent IF: 7.367; 2013 IF: 6.739
Call Number UA @ lucian @ c:irua:109249 Serial 1264
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Author Khalilov, U.; Pourtois, G.; Bogaerts, A.; van Duin, A.C.T.; Neyts, E.C.
Title Reactive molecular dynamics simulations on SiO2-coated ultra-small Si-nanowires Type A1 Journal article
Year 2013 Publication Nanoscale Abbreviated Journal Nanoscale
Volume 5 Issue 2 Pages 719-725
Keywords A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract The application of coreshell SiSiO2 nanowires as nanoelectronic devices strongly depends on their structure, which is difficult to tune precisely. In this work, we investigate the formation of the coreshell nanowires at the atomic scale, by reactive molecular dynamics simulations. The occurrence of two temperature-dependent oxidation mechanisms of ultra-small diameter Si-NWs is demonstrated. We found that control over the Si-core radius and the SiOx (x ≤ 2) oxide shell is possible by tuning the growth temperature and the initial Si-NW diameter. Two different structures were obtained, i.e., ultrathin SiO2 silica nanowires at high temperature and Si core|ultrathin SiO2 silica nanowires at low temperature. The transition temperature is found to linearly decrease with the nanowire curvature. Finally, the interfacial stress is found to be responsible for self-limiting oxidation, depending on both the initial Si-NW radius and the oxide growth temperature. These novel insights allow us to gain control over the exact morphology and structure of the wires, as is needed for their application in nanoelectronics.
Address
Corporate Author Thesis
Publisher Place of Publication Cambridge Editor
Language Wos 000313426200036 Publication Date 2012-11-16
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2040-3364;2040-3372; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 7.367 Times cited 17 Open Access
Notes Approved (up) Most recent IF: 7.367; 2013 IF: 6.739
Call Number UA @ lucian @ c:irua:102584 Serial 2824
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Author Khalilov, U.; Bogaerts, A.; Neyts, E.C.
Title Microscopic mechanisms of vertical graphene and carbon nanotube cap nucleation from hydrocarbon growth precursors Type A1 Journal article
Year 2014 Publication Nanoscale Abbreviated Journal Nanoscale
Volume 6 Issue 15 Pages 9206-9214
Keywords A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Controlling and steering the growth of single walled carbon nanotubes is often believed to require controlling of the nucleation stage. Yet, little is known about the microscopic mechanisms governing the nucleation from hydrocarbon molecules. Specifically, we address here the dehydrogenation of hydrocarbon molecules and the formation of all-carbon graphitic islands on metallic nanoclusters from hydrocarbon molecules under conditions typical for carbon nanotube growth. Employing reactive molecular dynamics simulations, we demonstrate for the first time that the formation of a graphitic network occurs through the intermediate formation of vertically oriented, not fully dehydrogenated graphitic islands. Upon dehydrogenation of these vertical graphenes, the islands curve over the surface, thereby forming a carbon network covering the nanoparticle. The results indicate that controlling the extent of dehydrogenation offers an additional parameter to control the nucleation of carbon nanotubes.
Address
Corporate Author Thesis
Publisher Place of Publication Cambridge Editor
Language Wos 000339861500103 Publication Date 2014-05-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2040-3364;2040-3372; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 7.367 Times cited 21 Open Access
Notes Approved (up) Most recent IF: 7.367; 2014 IF: 7.394
Call Number UA @ lucian @ c:irua:117950 Serial 2027
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Author Engelmann, Y.; Bogaerts, A.; Neyts, E.C.
Title Thermodynamics at the nanoscale : phase diagrams of nickel-carbon nanoclusters and equilibrium constants for face transitions Type A1 Journal article
Year 2014 Publication Nanoscale Abbreviated Journal Nanoscale
Volume 6 Issue Pages 11981-11987
Keywords A1 Journal article; PLASMANT
Abstract Using reactive molecular dynamics simulations, the melting behavior of nickelcarbon nanoclusters is examined. The phase diagrams of icosahedral and Wulff polyhedron clusters are determined using both the Lindemann index and the potential energy. Formulae are derived for calculating the equilibrium constants and the solid and liquid fractions during a phase transition, allowing more rational determination of the melting temperature with respect to the arbitrary Lindemann value. These results give more insight into the properties of nickelcarbon nanoclusters in general and can specifically be very useful for a better understanding of the synthesis of carbon nanotubes using the catalytic chemical vapor deposition method.
Address
Corporate Author Thesis
Publisher Place of Publication Cambridge Editor
Language Wos 000343000800049 Publication Date 2014-07-24
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2040-3364;2040-3372; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 7.367 Times cited 20 Open Access
Notes Approved (up) Most recent IF: 7.367; 2014 IF: 7.394
Call Number UA @ lucian @ c:irua:119408 Serial 3636
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Author Engelmann; Bogaerts, A.; Neyts, E.C.
Title Thermodynamics at the nanoscale: phase diagrams of nickel-carbon nanoclusters and equilibrium constants for phase transitions Type A1 Journal article
Year 2014 Publication Nanoscale Abbreviated Journal Nanoscale
Volume 6 Issue 20 Pages 11981-11987
Keywords A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Using reactive molecular dynamics simulations, the melting behavior of nickel-carbon nanoclusters is examined. The phase diagrams of icosahedral and Wulff polyhedron clusters are determined using both the Lindemann index and the potential energy. Formulae are derived for calculating the equilibrium constants and the solid and liquid fractions during a phase transition, allowing more rational determination of the melting temperature with respect to the arbitrary Lindemann value. These results give more insight into the properties of nickel-carbon nanoclusters in general and can specifically be very useful for a better understanding of the synthesis of carbon nanotubes using the catalytic chemical vapor deposition method.
Address
Corporate Author Thesis
Publisher Place of Publication Cambridge Editor
Language Wos 000343000800049 Publication Date 2014-07-24
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2040-3364;2040-3372; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 7.367 Times cited 20 Open Access
Notes Approved (up) Most recent IF: 7.367; 2014 IF: 7.394
Call Number UA @ lucian @ c:irua:121106 Serial 3637
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Author Neyts, E.C.; Ostrikov, K.; Han, Z.J.; Kumar, S.; van Duin, A.C.T.; Bogaerts, A.
Title Defect healing and enhanced nucleation of carbon nanotubes by low-energy ion bombardment Type A1 Journal article
Year 2013 Publication Physical review letters Abbreviated Journal Phys Rev Lett
Volume 110 Issue 6 Pages 065501-65505
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Structural defects inevitably appear during the nucleation event that determines the structure and properties of single-walled carbon nanotubes. By combining ion bombardment experiments with atomistic simulations we reveal that ion bombardment in a suitable energy range allows these defects to be healed resulting in an enhanced nucleation of the carbon nanotube cap. The enhanced growth of the nanotube cap is explained by a nonthermal ion-induced graphene network restructuring mechanism.
Address
Corporate Author Thesis
Publisher Place of Publication New York, N.Y. Editor
Language Wos 000314687300022 Publication Date 2013-02-07
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0031-9007;1079-7114; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 8.462 Times cited 50 Open Access
Notes Approved (up) Most recent IF: 8.462; 2013 IF: 7.728
Call Number UA @ lucian @ c:irua:105306 Serial 616
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Author Engelmann, Y.; Mehta, P.; Neyts, E.C.; Schneider, W.F.; Bogaerts, A.
Title Predicted Influence of Plasma Activation on Nonoxidative Coupling of Methane on Transition Metal Catalysts Type A1 Journal article
Year 2020 Publication Acs Sustainable Chemistry & Engineering Abbreviated Journal Acs Sustain Chem Eng
Volume 8 Issue 15 Pages 6043-6054
Keywords A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT); Movement Antwerp (MOVANT)
Abstract The combination of catalysis and nonthermal plasma holds promise for enabling difficult chemical conversions. The possible synergy between both depends strongly on the nature of the reactive plasma species and the catalyst material. In this paper, we show how vibrationally excited species and plasma-generated radicals interact with transition metal catalysts and how changing the catalyst material can improve the conversion rates and product selectivity. We developed a microkinetic model to investigate the impact of vibrational excitations and plasma-generated radicals on the nonoxidative coupling of methane over transition metal surfaces. We predict a significant increase in ethylene formation for vibrationally excited methane. Plasma-generated radicals have a stronger impact on the turnover frequencies with high selectivity toward ethylene on noble catalysts and mixed selectivity on non-noble catalysts. In general, we show how the optimal catalyst material depends on the desired products as well as the plasma conditions.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000526884000025 Publication Date 2020-04-20
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2168-0485 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 8.4 Times cited Open Access
Notes Herculesstichting; University of Notre Dame; Universiteit Antwerpen; Division of Engineering Education and Centers, EEC-1647722 ; We would like to thank Tom Butterworth for his work on methane vibrational distribution functions (VDF) and for sharing his thoughts and experiences on this matter, specifically regarding the VDF of the degenerate modes of methane. We ACS Sustainable Chemistry & Engineering pubs.acs.org/journal/ascecg Research Article https://dx.doi.org/10.1021/acssuschemeng.0c00906 ACS Sustainable Chem. Eng. 2020, 8, 6043−6054 6052 also acknowledge financial support from the DOC-PRO3 and the TOP-BOF projects of the University of Antwerp. 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. Support for W.F.S. was provided by the National Science Foundation under cooperative agreement no. EEC-1647722, an Engineering Research Center for the Innovative and Strategic Transformation of Alkane Resources (CISTAR). P.M. acknowledges support through the Eilers Graduate Fellowship of the University of Notre Dame. Approved (up) Most recent IF: 8.4; 2020 IF: 5.951
Call Number PLASMANT @ plasmant @c:irua:169228 Serial 6366
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Author Kovács, A.; Billen, P.; Cornet, I.; Wijnants, M.; Neyts, E.C.
Title Modeling the physicochemical properties of natural deep eutectic solvents : a review Type A1 Journal article
Year 2020 Publication Chemsuschem Abbreviated Journal Chemsuschem
Volume 13 Issue 15 Pages 3789-3804
Keywords A1 Journal article; Engineering sciences. Technology; Intelligence in PRocesses, Advanced Catalysts and Solvents (iPRACS); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT); Biochemical Wastewater Valorization & Engineering (BioWaVE)
Abstract Natural deep eutectic solvents (NADES) are mixtures of naturally derived compounds with a significantly decreased melting point due to the specific interactions among the constituents. NADES have benign properties (low volatility, flammability, toxicity, cost) and tailorable physicochemical properties (by altering the type and molar ratio of constituents), hence they are often considered as a green alternative to common organic solvents. Modeling the relation between their composition and properties is crucial though, both for understanding and predicting their behavior. Several efforts were done to this end, yet this review aims at structuring the present knowledge as an outline for future research. First, we reviewed the key properties of NADES and relate them to their structure based on the available experimental data. Second, we reviewed available modeling methods applicable to NADES. At the molecular level, density functional theory and molecular dynamics allow interpreting density differences and vibrational spectra, and computation of interaction energies. Additionally, properties at the level of the bulk media can be explained and predicted by semi-empirical methods based on ab initio methods (COSMO-RS) and equation of state models (PC-SAFT). Finally, methods based on large datasets are discussed; models based on group contribution methods and machine learning. A combination of bulk media and dataset modeling allows qualitative prediction and interpretation of phase equilibria properties on the one hand, and quantitative prediction of melting point, density, viscosity, surface tension and refractive indices on the other hand. In our view, multiscale modeling, combining the molecular and macroscale methods, will strongly enhance the predictability of NADES properties and their interaction with solutes, yielding truly tailorable solvents to accommodate (bio)chemical reactions.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000541499100001 Publication Date 2020-05-07
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1864-5631 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 8.4 Times cited Open Access
Notes Approved (up) Most recent IF: 8.4; 2020 IF: 7.226
Call Number UA @ admin @ c:irua:168851 Serial 6770
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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 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 (up) Most recent IF: 8.668
Call Number c:irua:131058 Serial 3986
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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 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 (up) Most recent IF: 8.668
Call Number c:irua:134577 c:irua:135670 Serial 4105
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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 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 (up) Most recent IF: 8.668
Call Number PLASMANT @ plasmant @c:irua:145519 Serial 4707
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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 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 (up) Most recent IF: 9.446
Call Number c:irua:129808 Serial 3984
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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 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 (up) Most recent IF: 9.446
Call Number PLASMANT @ plasmant @ c:irua:139514 Serial 4343
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Author Somers, W.; Bogaerts, A.; van Duin, A.C.T.; Neyts, E.C.
Title Interactions of plasma species on nickel catalysts : a reactive molecular dynamics study on the influence of temperature and surface structure Type A1 Journal article
Year 2014 Publication Applied catalysis : B : environmental Abbreviated Journal Appl Catal B-Environ
Volume 154 Issue Pages 1-8
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Methane reforming by plasma catalysis is a complex process that is far from understood. It requires a multidisciplinary approach which ideally takes into account all effects from the plasma on the catalyst, and vice versa. In this contribution, we focus on the interactions of CHx (x = {1,2,3}) radicals that are created in the plasma with several nickel catalyst surfaces. To this end, we perform reactive molecular dynamics simulations, based on the ReaxFF potential, in a wide temperature range of 4001600 K. First, we focus on the H2 formation as a function of temperature and surface structure. We observe that substantial H2 formation is obtained at 1400 K and above, while the role of the surface structure seems limited. Indeed, in the initial stage, the type of nickel surface influences the CH bond breaking efficiency of adsorbed radicals; however, the continuous carbon diffusion into the surface gradually diminishes the surface crystallinity and therefore reduces the effect of surface structure on the H2 formation probability. Furthermore, we have also investigated to what extent the species adsorbed on the catalyst surface can participate in surface reactions more in general, for the various surface structures and as a function of temperature. These results are part of the ongoing research on the methane reforming by plasma catalysis, a highly interesting yet complex alternative to conventional reforming processes.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000335098800001 Publication Date 2014-02-06
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 23 Open Access
Notes Approved (up) Most recent IF: 9.446; 2014 IF: 7.435
Call Number UA @ lucian @ c:irua:114607 Serial 1686
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