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Author Wang, Z.; Zhang, Y.; Neyts, E.C.; Cao, X.; Zhang, X.; Jang, B.W.-L.; Liu, C.-jun
Title Catalyst preparation with plasmas : how does it work? Type A1 Journal article
Year 2018 Publication ACS catalysis Abbreviated Journal Acs Catal
Volume 8 Issue 3 Pages 2093-2110
Keywords (up) A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Catalyst preparation with plasmas is increasingly attracting interest. A plasma is a partially ionized gas, consisting of electrons, ions, molecules, radicals, photons, and excited species, which are all active species for catalyst preparation and treatment. Under the influence of plasma, nucleation and crystal growth in catalyst preparation can be very different from those in the conventional thermal approach. Some thermodynamically unfavorable reactions can easily take place with plasmas. Compounds such as sulfides, nitrides, and phosphides that are produced under harsh conditions can be synthesized by plasma under mild conditions. Plasmas can produce catalysts with smaller particle sizes and controllable structure. Plasma is also a facile tool for reduction, oxidation, doping, etching, coating, alloy formation, surface treatment, and surface cleaning in a simple and direct way. A rapid and convenient plasma template removal has thus been established for zeolite synthesis. It can operate at room temperature and allows the catalyst preparation on temperature-sensitive supporting materials. Plasma is typically effective for the production of various catalysts on metallic substrates. In addition, plasma-prepared transition-metal catalysts show enhanced low-temperature activity with improved stability. This provides a useful model catalyst for further improvement of industrial catalysts. In this review, we aim to summarize the recent advances in catalyst preparation with plasmas. The present understanding of plasma-based catalyst preparation is discussed. The challenges and future development are addressed.
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Corporate Author Thesis
Publisher Amer chemical soc Place of Publication Washington Editor
Language Wos 000426804100055 Publication Date 2018-01-29
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2155-5435 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 10.614 Times cited 81 Open Access Not_Open_Access
Notes Approved Most recent IF: 10.614
Call Number UA @ lucian @ c:irua:150880 Serial 4963
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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 (up) 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.
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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 Most recent IF: 6.337
Call Number PLASMANT @ plasmant @c:irua:152172 Serial 4993
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Author Zhang, Y.-R.; Neyts, E.C.; Bogaerts, A.
Title Enhancement of plasma generation in catalyst pores with different shapes Type A1 Journal article
Year 2018 Publication Plasma sources science and technology Abbreviated Journal Plasma Sources Sci T
Volume 27 Issue 5 Pages 055008
Keywords (up) A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Plasma generation inside catalyst pores is of utmost importance for plasma catalysis, as the existence of plasma species inside the pores affects the active surface area of the catalyst available to the plasma species for catalytic reactions. In this paper, the electric field enhancement, and thus the plasma production inside catalyst pores with different pore shapes is studied with a two-dimensional fluid model. The results indicate that the electric field will be significantly enhanced near tip-like structures. In a conical pore with small opening, the strongest electric field appears at the opening and bottom corners of the pore, giving rise to a prominent ionization rate throughout the pore. For a cylindrical pore, the electric field is only enhanced at the bottom corners of the pore, with lower absolute value, and thus the ionization rate inside the pore is only slightly enhanced. Finally, in a conical pore with large opening, the electric field is characterized by a maximum at the bottom of the pore, yielding a similar behavior for the ionization rate. These results demonstrate that the shape of the pore has a significantly influence on the electric field enhancement, and thus modifies the plasma properties.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000432351700002 Publication Date 2018-05-15
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 11 Open Access OpenAccess
Notes This work was supported by the Fund for Scientific Research Flanders (FWO) (Grant No. G.0217.14N) and the Fundamental Research Funds for the Central Universities (Grant No. DUT17LK52). Approved Most recent IF: 3.302
Call Number PLASMANT @ plasmant @c:irua:151546 Serial 4998
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Author Nematollahi, P.; Esrafili, M.D.; Neyts, E.C.
Title The role of healed N-vacancy defective BC2N sheet and nanotube by NO molecule in oxidation of NO and CO gas molecules Type A1 Journal article
Year 2018 Publication Surface science : a journal devoted to the physics and chemistry of interfaces Abbreviated Journal Surf Sci
Volume 672-673 Issue 672-673 Pages 39-46
Keywords (up) A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract In this study, the healing of N-vacancy boron carbonitride nanosheet (NV-BC2NNS) and nanotube (NV-BC2NNT) by NO molecule is studied by means of density functional theory calculations. Two different N-vacancies are considered in each of these structures in which the vacancy site is surrounded by either three B-atoms (NB) or by two B- and one C-atom (NBC). By means of the healed BC2NNS and BC2NNT as a support, the removal of two toxic gas molecules (NO and CO) are applicable. It should be noted that the obtained energy barriers of both healing and oxidizing processes are significantly lower than those of graphene, carbon nanotubes or boron nitride nanostructures. Also, at the end of the oxidation process, the pure BC2NNS or BC2NNT is obtained without any additional defects. Therefore, by using this method, we can considerably purify the defective BC2NNS/BC2NNT. Moreover, according to the thermochemistry calculations we can further confirm that the healing process of the NV-BC2NNS and NV-BC2NNT by NO are feasible at room temperature. So, we can claim that this study could be very helpful in both purifying the defective BC2NNS/BC2NNT while in the same effort removing toxic NO and CO gases.
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Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000432614700007 Publication Date 2018-03-08
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0039-6028 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.062 Times cited 1 Open Access OpenAccess
Notes Approved Most recent IF: 2.062
Call Number UA @ lucian @ c:irua:151478 Serial 5044
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Author Heyne, M.H.; de Marneffe, J.-F.; Radu, I.; Neyts, E.C.; De Gendt, S.
Title Thermal recrystallization of short-range ordered WS2 films Type A1 Journal article
Year 2018 Publication Journal of vacuum science and technology: A: vacuum surfaces and films Abbreviated Journal J Vac Sci Technol A
Volume 36 Issue 5 Pages 05g501
Keywords (up) A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract The integration of van der Waals materials in nanoelectronic devices requires the deposition of few-layered MX2 films with excellent quality crystals covering a large area. In recent years, astonishing progress in the monolayer growth of WS2 and MoS2 was demonstrated, but multilayer growth resulted often in separated triangular or hexagonal islands. These polycrystalline films cannot fully employ the specific MX2 properties since they are not connected in-plane to the other domains. To coalesce separated islands, ultrahigh-temperature postdeposition anneals in H2S are applied, which are not compatible with bare silicon substrates. Starting from the deposition of stoichiometric short-ordered films, the present work studies different options for subsequent high-temperature annealing in an inert atmosphere to form crystalline films with large grains from stoichiometric films with small grains. The rapid thermal annealing, performed over a few seconds, is compared to excimer laser annealing in the nanosecond range, which are both able to crystallize the thin WS2. The WS2 recrystallization temperature can be lowered using metallic crystallization promoters (Co and Ni). The best result is obtained using a Co cap, due to the circumvention of Co and S binary phase formation below the eutectic temperature. The recrystallization above a critical temperature is accompanied by sulfur loss and 3D regrowth. These undesired effects can be suppressed by the application of a dielectric capping layer prior to annealing. A SiO2 cap can suppress the sulfur loss successfully during annealing and reveals improved material quality in comparison to noncapped films Published by the AVS.
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Corporate Author Thesis
Publisher Place of Publication New York, N.Y. Editor
Language Wos 000444033200002 Publication Date 2018-07-05
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0734-2101 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.374 Times cited 2 Open Access Not_Open_Access
Notes Approved Most recent IF: 1.374
Call Number UA @ lucian @ c:irua:153671 Serial 5134
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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 (up) 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 Most recent IF: 6.337
Call Number PLASMANT @ plasmant @c:irua:160695 Serial 5187
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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 (up) 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.
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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 Most recent IF: 6.937
Call Number UA @ admin @ c:irua:160229 Serial 5266
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Author Grubova, I.Y.; Surmeneva, M.A.; Huygh, S.; Surmenev, R.A.; Neyts, E.C.
Title Effects of silicon doping on strengthening adhesion at the interface of the hydroxyapatite-titanium biocomposite : a first-principles study Type A1 Journal article
Year 2019 Publication Computational materials science Abbreviated Journal Comp Mater Sci
Volume 159 Issue 159 Pages 228-234
Keywords (up) A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract In this paper we employ first-principles calculations to investigate the effect of substitutional Si doping in the amorphous calcium-phosphate (a-HAP) structure on the work of adhesion, integral charge transfer, charge density difference and theoretical tensile strengths between an a-HAP coating and amorphous titanium dioxide (a-TiO2) substrate systemically. Our calculations demonstrate that substitution of a P atom by a Si atom in a-HAP (a-Si-HAP) with the creation of OH-vacancies as charge compensation results in a significant increase of the bonding strength of the coating to the substrate. The work of adhesion of the optimized Si-doped interfaces reaches a value of up to -2.52 J m(-2), which is significantly higher than for the stoichiometric a-HAP/a-TiO2. Charge density difference analysis indicates that the dominant interactions at the interface have significant covalent character, and in particular two Ti-O and three Ca-O bonds are formed for a-Si-HAP/a-TiO2 and one Ti-O and three Ca-O bonds for a-HAP/a-TiO2. From the stress-strain curve, the Young's modulus of a-Si-HAP/a-TiO2 is calculated to be about 25% higher than that of the a-HAP/a-TiO2, and the yielding stress is about 2 times greater than that of the undoped model. Our calculations therefore demonstrate that the presence of Si in the a-HAP structure strongly alters not only the bioactivity and resorption rates, but also the mechanical properties of the a-HAP/a-TiO2 interface. The results presented here provide an important theoretical insight into the nature of the chemical bonding at the a-HAP/a-TiO2 interface, and are particularly significant for the practical medical applications of HAP-based biomaterials.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000457856900023 Publication Date 2018-12-18
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0927-0256 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.292 Times cited 1 Open Access Not_Open_Access
Notes Approved Most recent IF: 2.292
Call Number UA @ admin @ c:irua:157480 Serial 5272
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Author Nematollahi, P.; Neyts, E.C.
Title Direct methane conversion to methanol on M and MN4 embedded graphene (M = Ni and Si): a comparative DFT study Type A1 Journal article
Year 2019 Publication Applied surface science Abbreviated Journal Appl Surf Sci
Volume 496 Issue 496 Pages 143618
Keywords (up) A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract The ever increasing global production and dispersion of methane requires novel chemistry to transform it into easily condensable energy carriers that can be integrated into the chemical infrastructure. In this context, single atom catalysts have attracted considerable interest due to their outstanding catalytic activity. We here use density functional theory (DFT) computations to compare the reaction and activation energies of M and MN4 embedded graphene (M = Ni and Si) on the methane-to-methanol conversion near room temperature. Thermodynamically, conversion of methane to methanol is energetically favorable at ambient conditions. Both singlet and triplet spin state of the studied systems are considered in all of the calculations. The DFT results show that the barriers are significantly lower when the complexes are in the triplet state than in the singlet state. In particular, Si-G with the preferred spin multiplicity of triplet seems to be viable catalysts for methane oxidation thanks to the corresponding lower energy barriers and higher stability of the obtained configurations. Our results provide insights into the nature of methane conversion and may serve as guidance for fabricating cost-effective graphene-based single atom catalysts.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000488957400004 Publication Date 2019-08-12
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 2 Open Access
Notes Approved Most recent IF: 3.387
Call Number UA @ admin @ c:irua:163695 Serial 6294
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Author Fukuhara, S.; Bal, K.M.; Neyts, E.C.; Shibuta, Y.
Title Accelerated molecular dynamics simulation of large systems with parallel collective variable-driven hyperdynamics Type A1 Journal article
Year 2020 Publication Computational Materials Science Abbreviated Journal Comp Mater Sci
Volume 177 Issue Pages 109581
Keywords (up) A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract The limitation in time and length scale is a major issue of molecular dynamics (MD) simulation. Although several methods have been developed to extend the MD time scale, their performance usually deteriorates with increasing system size. Therefore, an acceleration method which is applicable to large systems is required to bridge the gap between the MD simulations and target phenomena. In this study, an accelerated MD method for large system is developed based on the collective variable-driven hyperdynamics (CVHD) method [K.M. Bal and E.C. Neyts, 2015]. The key idea is to run CVHD in parallel with rate control and accelerate multiple possible events simultaneously. Using this novel method, carbon diffusion in bcc-iron bicrystal with grain boundary is examined as an application for practical materials. Carbon atoms reaching at the grain boundary are trapped whereas carbon atoms in the bulk region diffuse randomly, and both dynamic regimes can be simultaneously accelerated with the parallel CVHD technique.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000519576300001 Publication Date 2020-02-08
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0927-0256 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.3 Times cited Open Access
Notes JSPS, J22727 ; Japan Society for the Promotion of Science; 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 Leading Graduate Schools (MERIT). Data availability The data required to reproduce these findings are available from the corresponding authors upon reasonable request. Approved Most recent IF: 3.3; 2020 IF: 2.292
Call Number PLASMANT @ plasmant @c:irua:166773 Serial 6333
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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 (up) 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 Most recent IF: 6.337
Call Number PLASMANT @ plasmant @c:irua:172459 Serial 6414
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Author Bal, K.M.; Fukuhara, S.; Shibuta, Y.; Neyts, E.C.
Title Free energy barriers from biased molecular dynamics simulations Type A1 Journal article
Year 2020 Publication Journal Of Chemical Physics Abbreviated Journal J Chem Phys
Volume 153 Issue 11 Pages 114118
Keywords (up) A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Atomistic simulation methods for the quantification of free energies are in wide use. These methods operate by sampling the probability density of a system along a small set of suitable collective variables (CVs), which is, in turn, expressed in the form of a free energy surface (FES). This definition of the FES can capture the relative stability of metastable states but not that of the transition state because the barrier height is not invariant to the choice of CVs. Free energy barriers therefore cannot be consistently computed from the FES. Here, we present a simple approach to calculate the gauge correction necessary to eliminate this inconsistency. Using our procedure, the standard FES as well as its gauge-corrected counterpart can be obtained by reweighing the same simulated trajectory at little additional cost. We apply the method to a number of systems—a particle solvated in a Lennard-Jones fluid, a Diels–Alder reaction, and crystallization of liquid sodium—to demonstrate its ability to produce consistent free energy barriers that correctly capture the kinetics of chemical or physical transformations, and discuss the additional demands it puts on the chosen CVs. Because the FES can be converged at relatively short (sub-ns) time scales, a free energy-based description of reaction kinetics is a particularly attractive option to study chemical processes at more expensive quantum mechanical levels of theory.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000574665600004 Publication Date 2020-09-21
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0021-9606 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.4 Times cited Open Access
Notes Japan Society for the Promotion of Science, 19H02415 18J22727 ; Fonds Wetenschappelijk Onderzoek, 12ZI420N ; This work was supported, in part, by a Grant-in-Aid for Scientific Research (B) (Grant No. 19H02415) and Grant-in-Aid for a JSPS Research Fellow (Grant No. 18J22727) from the Japan Society for the Promotion of Science (JSPS), Japan. K.M.B. was funded as a junior postdoctoral fellow of the FWO (Research Foundation – Flanders), Grant No. 12ZI420N. S.F. was supported by JSPS through the Program for Leading Graduate Schools (MERIT). The computational resources and services used in this work were provided by the HPC core facility CalcUA of the Universiteit Antwerpen, and VSC (Flemish Supercomputer Center), funded by the FWO and the Flemish Government. The authors are grateful to Pablo Piaggi for making the pair entropy CV code publicly available. Approved Most recent IF: 4.4; 2020 IF: 2.965
Call Number PLASMANT @ plasmant @c:irua:172456 Serial 6420
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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 (up) 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 Most recent IF: 6.337
Call Number PLASMANT @ plasmant @c:irua:172452 Serial 6421
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Author Nematollahi, P.; Neyts, E.C.
Title Direct oxidation of methane to methanol on Co embedded N-doped graphene: Comparing the role of N₂O and O₂ as oxidants Type A1 Journal article
Year 2020 Publication Applied Catalysis A-General Abbreviated Journal Appl Catal A-Gen
Volume 602 Issue Pages 117716-10
Keywords (up) A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract In this work, the effects of N-doping into the Co-doped single vacancy (Co-SV-G) and di-vacancy graphene flake (Co-dV-G) are investigated and compared toward direct oxidation of methane to methanol (DOMM) employing two different oxidants (N2O and O-2) using density functional theory (DFT) calculation. We found that DOMM on CoN3-G utilizing the N2O molecule as oxygen-donor proceeds via a two-step reaction with low activation energies. In addition, we found that although CoN3-G might be a good catalyst for methane conversion, it can also catalyze the oxidation of methanol to CO2 and H2O due to the required low activation barriers. Moreover, the adsorption behaviors of CHx (x = 0-4) species and dehydrogenation of CHx (x = 1-4) species on CoN3-G are investigated. We concluded that CoN3-G can be used as an efficient catalyst for DOMM and N-2O reduction at ambient conditions which may serve as a guide for fabricating effective C/N catalysts in energy-related devices.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000554006800046 Publication Date 2020-06-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0926-860x ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 5.5 Times cited Open Access
Notes ; This work was performed with the financial support from the Doctoral Fund of the Antwerp University (NO. BOFLP33099). All the simulations are performed on resources provided by the high-performance computing center of Antwerp University. ; Approved Most recent IF: 5.5; 2020 IF: 4.339
Call Number UA @ admin @ c:irua:171219 Serial 6485
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Author Grubova, I.Y.; Surmeneva, M.A.; Surmenev, R.A.; Neyts, E.C.
Title Effect of van der Waals interactions on the adhesion strength at the interface of the hydroxyapatite-titanium biocomposite : a first-principles study Type A1 Journal article
Year 2020 Publication RSC advances Abbreviated Journal
Volume 10 Issue 62 Pages 37800-37805
Keywords (up) A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Hydroxyapatite (HAP) is frequently used as biocompatible coating on Ti-based implants. In this context, the HAP-Ti adhesion is of crucial importance. Here, we report ab initio calculations to investigate the influence of Si incorporation into the amorphous calcium-phosphate (a-HAP) structure on the interfacial bonding mechanism between the a-HAP coating and an amorphous titanium dioxide (a-TiO2) substrate, contrasting two different density functionals: PBE-GGA, and DFT-D3, which are capable of describing the influence of the van der Waals (vdW) interactions. In particular, we discuss the effect of dispersion on the work of adhesion (W-ad), equilibrium geometries, and charge density difference (CDD). We find that replacement of P by Si in a-HAP (a-Si-HAP) with the creation of OH vacancies as charge compensation results in a significant increase in the bond strength between the coating and substrate in the case of using the PBE-GGA functional. However, including the vdW interactions shows that these forces considerably contribute to the W-ad. We show that the difference (W-ad – W-ad(vdW)) is on average more than 1.1 J m(-2) and 0.5 J m(-2) for a-HAP/a-TiO2 and a-Si-HAP/a-TiO2, respectively. These results reveal that including vdW interactions is essential for accurately describing the chemical bonding at the a-HAP/a-TiO2 interface.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000583523300025 Publication Date 2020-10-14
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited Open Access
Notes ; The authors gratefully acknowledge financial support from the Russian president's grant MK-330.2020.8 and BOF Fellowships for International Joint PhD students funded by University of Antwerp (UAntwerp, project number 32545). The work was carried out at Tomsk Polytechnic University within the framework of Tomsk Polytechnic University Competitiveness Enhancement Program grant and in part using the Turing HPC infrastructure of the CalcUA core facility of the UAntwerp, a division of the Flemish Supercomputer Centre (VSC), funded by the Hercules Foundation, the Flemish Government (department EWI) and the UAntwerp, Belgium. ; Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:173603 Serial 6499
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Author Yi, Y.; Wang, X.; Jafarzadeh, A.; Wang, L.; Liu, P.; He, B.; Yan, J.; Zhang, R.; Zhang, H.; Liu, X.; Guo, H.; Neyts, E.C.; Bogaerts, A.
Title Plasma-Catalytic Ammonia Reforming of Methane over Cu-Based Catalysts for the Production of HCN and H2at Reduced Temperature Type A1 Journal article
Year 2021 Publication Acs Catalysis Abbreviated Journal Acs Catal
Volume 11 Issue 3 Pages 1765-1773
Keywords (up) A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Industrial production of HCN from NH3 and CH4 not only uses precious Pt or Pt−Rh catalysts but also requires extremely high temperatures (∼1600 K). From an energetic, operational, and safety perspective, a drastic decrease in temperature is highly desirable. Here, we report ammonia reforming of methane for the production of HCN and H2 at 673 K by the combination of CH4/NH3 plasma and a supported Cu/silicalite-1 catalyst. 30% CH4 conversion has been achieved with 79% HCN selectivity. Catalyst characterization and plasma diagnostics reveal that the excellent reaction performance is attributed to metallic Cu active sites. In addition, we propose a possible reaction pathway, viz. E-R reactions with N, NH, NH2, and CH radicals produced in the plasma, for the production of HCN, based on density functional theory calculations. Importantly, the Cu/silicalite-1 catalyst costs less than 5% of the commercial Pt mesh catalyst.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000618540300057 Publication Date 2021-02-05
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2155-5435 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 10.614 Times cited Open Access OpenAccess
Notes Universiteit Antwerpen, 32249 ; China Postdoctoral Science Foundation, 2015M580220 2016T90217 ; PetroChina Innovation Foundation, 2018D-5007-0501 ; National Natural Science Foundation of China, 21503032 ; We acknowledge financial support from the National Natural Science Foundation of China [21503032], the China Postdoctoral Science Foundation [grant numbers 2015M580220 and 2016T90217, 2016], the PetroChina Innovation Foundation [2018D-5007-0501], and the TOP research project of the Research Fund of the University of Antwerp [grant ID 32249]. Approved Most recent IF: 10.614
Call Number PLASMANT @ plasmant @c:irua:175880 Serial 6675
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Author Berdiyorov, G.R.; Khalilov, U.; Hamoudi, H.; Neyts, E.C.
Title Effect of chemical modification on electronic transport properties of carbyne Type A1 Journal article
Year 2021 Publication Journal Of Computational Electronics Abbreviated Journal J Comput Electron
Volume Issue Pages
Keywords (up) A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Using density functional theory in combination with the Green’s functional formalism, we study the effect of surface functionalization on the electronic transport properties of 1D carbon allotrope—carbyne. We found that both hydrogenation and fluorination result in structural changes and semiconducting to metallic transition. Consequently, the current in the functionalization systems increases significantly due to strong delocalization of electronic states along the carbon chain. We also study the electronic transport in partially hydrogenated carbyne and interface structures consisting of pristine and functionalized carbyne. In the latter case, current rectification is obtained in the system with rectification ratio up to 50%. These findings can be useful for developing carbyne-based structures with tunable electronic transport properties.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000617664900001 Publication Date 2021-02-13
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1569-8025 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.526 Times cited Open Access OpenAccess
Notes Computational resources were provided by the research computing facilities of Qatar Environment and Energy Research Institute. Calculations are also conducted 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. U. Khalilov gratefully acknowledges financial support from the Fund of Scientific Research Flanders (FWO), Belgium, Grant number 12M1315N. Approved Most recent IF: 1.526
Call Number PLASMANT @ plasmant @c:irua:176169 Serial 6708
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Author Izadi, M.E.; Bal, K.M.; Maghari, A.; Neyts, E.C.
Title Reaction mechanisms of C(3PJ) and C+(2PJ) with benzene in the interstellar medium from quantum mechanical molecular dynamics simulations Type A1 Journal article
Year 2021 Publication Physical Chemistry Chemical Physics Abbreviated Journal Phys Chem Chem Phys
Volume 23 Issue 7 Pages 4205-4216
Keywords (up) A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract While spectroscopic data on small hydrocarbons in interstellar media in combination with crossed molecular beam (CMB) experiments have provided a wealth of information on astrochemically relevant species, much of the underlying mechanistic pathways of their formation remain elusive. Therefore, in this work, the chemical reaction mechanisms of C(<sup>3</sup>P<sub>J</sub>) + C<sub>6</sub>H<sub>6</sub>and C<sup>+</sup>(<sup>2</sup>P) + C<sub>6</sub>H<sub>6</sub>systems using the quantum mechanical molecular dynamics (QMMD) technique at the PBE0-D3(BJ) level of theory is investigated, mimicking a CMB experiment. Both the dynamics of the reactions as well as the electronic structure for the purpose of the reaction network are evaluated. The method is validated for the first reaction by comparison to the available experimental data. The reaction scheme for the C(<sup>3</sup>P<sub>J</sub>) + C<sub>6</sub>H<sub>6</sub>system covers the literature data,<italic>e.g.</italic>the major products are the 1,2-didehydrocycloheptatrienyl radical (C<sub>7</sub>H<sub>5</sub>) and benzocyclopropenyl radical (C<sub>6</sub>H<sub>5</sub>–CH), and it reveals the existence of less common pathways for the first time. The chemistry of the C<sup>+</sup>(<sup>2</sup>P<sub>J</sub>) + C<sub>6</sub>H<sub>6</sub>system is found to be much richer, and we have found that this is because of more exothermic reactions in this system in comparison to those in the C(<sup>3</sup>P<sub>J</sub>) + C<sub>6</sub>H<sub>6</sub>system. Moreover, using the QMMD simulation, a number of reaction paths have been revealed that produce three distinct classes of reaction products with different ring sizes. All in all, at all the collision energies and orientations, the major product is the heptagon molecular ion for the ionic system. It is also revealed that the collision orientation has a dominant effect on the reaction products in both systems, while the collision energy mostly affects the charged system. These simulations both prove the applicability of this approach to simulate crossed molecular beams, and provide fundamental information on reactions relevant for the interstellar medium.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000621595300016 Publication Date 2021-01-18
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 Open Access OpenAccess
Notes Fonds Wetenschappelijk Onderzoek, 12ZI420N ; Ministry of Science Research and Technology; Universiteit Antwerpen; The financial support from the Iran Ministry of Science, Research and Technology and PLASMANT Research Group University of Antwerp is highly acknowledged by the authors. K.M.B. was funded as a junior postdoctoral fellow of the FWO (Research Foundation – Flanders), Grant 12ZI420N. The computational resources and services used in this work were provided by the HPC core facility CalcUA of the Universiteit Antwerpen, and VSC (Flemish Supercomputer Center), funded by the FWO and the Flemish Government. Approved Most recent IF: 4.123
Call Number PLASMANT @ plasmant @c:irua:176672 Serial 6742
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Author Bogaerts, A.; Neyts, E.C.; Guaitella, O.; Murphy, A.B.
Title Foundations of plasma catalysis for environmental applications Type A1 Journal article
Year 2022 Publication Plasma Sources Science & Technology Abbreviated Journal Plasma Sources Sci T
Volume Issue Pages
Keywords (up) A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Plasma catalysis is gaining increasing interest for various applications, but the underlying mechanisms are still far from understood. Hence, more fundamental research is needed to understand these mechanisms. This can be obtained by both modelling and experiments. This foundations paper describes the fundamental insights in plasma catalysis, as well as efforts to gain more insights by modelling and experiments. Furthermore, it discusses the state-of-the-art of the major plasma catalysis applications, as well as successes and challenges of technology transfer of these applications.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000804396200001 Publication Date 2022-03-21
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0963-0252 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.8 Times cited Open Access OpenAccess
Notes H2020 Marie Skłodowska-Curie Actions, 823745 ; H2020 European Research Council, 810182 ; We acknowldege financial support from the European Research Council (ERC) under the European Union’s Horizon 2020 Research and Innovation programme (Grant Agreement No. 810182 – SCOPE ERC Synergy project) and the European Union’s Horizon 2020 Research and Innovation programme under the Marie Sklodowska-Curie Grant Agreement No. 813393 (PIONEER). Approved Most recent IF: 3.8
Call Number PLASMANT @ plasmant @c:irua:188539 Serial 7070
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Author Nematollahi, P.; Neyts, E.C.
Title Distribution pattern of metal atoms in bimetal-doped pyridinic-N₄ pores determines their potential for electrocatalytic N₂ reduction Type A1 Journal article
Year 2022 Publication Journal Of Physical Chemistry A Abbreviated Journal J Phys Chem A
Volume 126 Issue 20 Pages 3080-3089
Keywords (up) A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Doping two single transition-metal (TM) atoms on a substrate host opens numerous possibilities for catalyst design. However, what if the substrate contains more than one vacancy site? Then, the combination of two TMs along with their distribution patterns becomes a design parameter potentially complementary to the substrate itself and the bimetal composition. In this study, we investigate ammonia synthesis under mild electrocatalytic conditions on a transition-metal-doped porous C24N24 catalyst using density functional theory (DFT). The TMs studied include Ti, Mn, and Cu in a 2:4 dopant ratio (Ti2Mn4@C24N24 and Ti2Cu4@N-24(24)). Our computations show that a single Ti atom in both catalysts exhibits the highest selectivity for N-2 fixation at ambient conditions. This work is a good theoretical model to establish the structure-activity relationship, and the knowledge earned from the metal-N-4 moieties may help studies of related nanomaterials, especially those with curved structures.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000804119800003 Publication Date 2022-05-12
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1089-5639; 1520-5215 ISBN Additional Links UA library record; WoS full record
Impact Factor 2.9 Times cited Open Access OpenAccess
Notes Approved Most recent IF: 2.9
Call Number UA @ admin @ c:irua:189023 Serial 7146
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Author Cui, Z.; Meng, S.; Yi, Y.; Jafarzadeh, A.; Li, S.; Neyts, E.C.; Hao, Y.; Li, L.; Zhang, X.; Wang, X.; Bogaerts, A.
Title Plasma-catalytic methanol synthesis from CO₂ hydrogenation over a supported Cu cluster catalyst : insights into the reaction mechanism Type A1 Journal article
Year 2022 Publication Acs Catalysis Abbreviated Journal Acs Catal
Volume 12 Issue 2 Pages 1326-1337
Keywords (up) A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Plasma-catalytic CO, hydrogenation for methanol production is gaining increasing interest, but our understanding of its reaction mechanism remains primitive. We present a combined experimental/computational study on plasma-catalytic CO, hydrogenation to CH3OH over a size-selected Cu/gamma-Al2O3 catalyst. Our experiments demonstrate a synergistic effect between the Cu/gamma-Al2O3 catalyst and the CO2/H-2 plasma, achieving a CO2 conversion of 10% at 4 wt % Cu loading and a CH3OH selectivity near 50% further rising to 65% with H2O addition (for a H2O/CO2 ratio of 1). Furthermore, the energy consumption for CH3OH production was more than 20 times lower than with plasma only. We carried out density functional theory calculations over a Cu-13/gamma-Al2O3 model, which reveal that the interfacial sites of the Cu-13 cluster and gamma-Al2O3 support show a bifunctional effect: they not only activate the CO2 molecules but also strongly adsorb key intermediates to promote their hydrogenation further. Reactive plasma species can regulate the catalyst surface reactions via the Eley-Rideal (E-R) mechanism, which accelerates the hydrogenation process and promotes the generation of the key intermediates. H2O can promote the CH3OH desorption by competitive adsorption over the Cu-13/gamma-Al2O3 surface. This study provides new insights into CO2 hydrogenation through plasma catalysis, and it provides inspiration for the conversion of some other small molecules (CH4, N-2, CO, etc.) by plasma catalysis using supported-metal clusters.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000742735600001 Publication Date 2022-01-07
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2155-5435 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 12.9 Times cited Open Access OpenAccess
Notes Approved Most recent IF: 12.9
Call Number UA @ admin @ c:irua:186416 Serial 7192
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Author Bal, K.M.; Neyts, E.C.
Title Extending and validating bubble nucleation rate predictions in a Lennard-Jones fluid with enhanced sampling methods and transition state theory Type A1 Journal article
Year 2022 Publication Journal Of Chemical Physics Abbreviated Journal J Chem Phys
Volume 157 Issue 18 Pages 184113-10
Keywords (up) A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract We calculate bubble nucleation rates in a Lennard-Jones fluid through explicit molecular dynamics simulations. Our approach-based on a recent free energy method (dubbed reweighted Jarzynski sampling), transition state theory, and a simple recrossing correction-allows us to probe a fairly wide range of rates in several superheated and cavitation regimes in a consistent manner. Rate predictions from this approach bridge disparate independent literature studies on the same model system. As such, we find that rate predictions based on classical nucleation theory, direct brute force molecular dynamics simulations, and seeding are consistent with our approach and one another. Published rates derived from forward flux sampling simulations are, however, found to be outliers. This study serves two purposes: First, we validate the reliability of common modeling techniques and extrapolation approaches on a paradigmatic problem in materials science and chemical physics. Second, we further test our highly generic recipe for rate calculations, and establish its applicability to nucleation processes.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000885260600002 Publication Date 2022-11-14
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0021-9606 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.4 Times cited Open Access OpenAccess
Notes Approved Most recent IF: 4.4
Call Number UA @ admin @ c:irua:192076 Serial 7266
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Author Grubova, I.Y.; Surmenev, R.A.; Neyts, E.C.; Koptyug, A.V.; Volkova, A.P.; Surmeneva, M.A.
Title Combined first-principles and experimental study on the microstructure and mechanical characteristics of the multicomponent additive-manufactured Ti-35Nb-7Zr-5Ta alloy Type A1 Journal article
Year 2023 Publication ACS Omega Abbreviated Journal
Volume 8 Issue 30 Pages 27519-27533
Keywords (up) A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract New & beta;-stabilizedTi-based alloys are highly promising forbone implants, thanks in part to their low elasticity. The natureof this elasticity, however, is as yet unknown. We here present combinedfirst-principles DFT calculations and experiments on the microstructure,structural stability, mechanical characteristics, and electronic structureto elucidate this origin. Our results suggest that the studied & beta;Ti-35Nb-7Zr-5Ta wt % (TNZT) alloy manufacturedby the electron-beam powder bed fusion (E-PBF) method has homogeneousmechanical properties (H = 2.01 & PLUSMN; 0.22 GPa and E = 69.48 & PLUSMN; 0.03 GPa) along the building direction,which is dictated by the crystallographic texture and microstructuremorphologies. The analysis of the structural and electronic properties,as the main factors dominating the chemical bonding mechanism, indicatesthat TNZT has a mixture of strong metallic and weak covalent bonding.Our calculations demonstrate that the softening in the Cauchy pressure(C & PRIME; = 98.00 GPa) and elastic constant C ̅ ( 44 ) = 23.84 GPa is the originof the low elasticity of TNZT. Moreover, the nature of this softeningphenomenon can be related to the weakness of the second and thirdneighbor bonds in comparison with the first neighbor bonds in theTNZT. Thus, the obtained results indicate that a carefully designedTNZT alloy can be an excellent candidate for the manufacturing oforthopedic internal fixation devices. In addition, the current findingscan be used as guidance not only for predicting the mechanical propertiesbut also the nature of elastic characteristics of the newly developedalloys with yet unknown properties.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 001031269000001 Publication Date 2023-07-18
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2470-1343 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.1 Times cited Open Access
Notes Approved Most recent IF: 4.1; 2023 IF: NA
Call Number UA @ admin @ c:irua:198313 Serial 9011
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Author Kovács, A.; Yusupov, M.; Cornet, I.; Billen, P.; Neyts, E.C.
Title Effect of natural deep eutectic solvents of non-eutectic compositions on enzyme stability Type A1 Journal article
Year 2022 Publication Journal Of Molecular Liquids Abbreviated Journal J Mol Liq
Volume 366 Issue Pages 120180-17
Keywords (up) A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT); Biochemical Wastewater Valorization & Engineering (BioWaVE); Intelligence in PRocesses, Advanced Catalysts and Solvents (iPRACS)
Abstract Natural deep eutectic solvents (NADES) represent a green alternative to common organic solvents in the biochemical industry due to their benign behavior and tailorable properties, in particular as media for enzymatic reactions. However, to fully exploit their potential in enzymatic reactions, there is a need for a more fundamental understanding of how these neoteric solvents influence the course of these reac-tions. Thus, the aim of this study is to investigate the influence of NADES with various molar composi-tions on the stability and structure of enzymes, applying molecular dynamics simulations. This can help to better understand the effect of individual compounds of NADES, in addition to eutectic mixtures. More specifically, we simulate the behavior of Candida antarctica lipase B (CALB) enzyme in NADES com-posed of choline chloride with either urea, ethylene glycol or glycerol. Hereto, we monitor the NADES microstructure, the general stability of the enzyme and changes in the structure of its active sites and sur-face residues. Our simulations show that none of the studied NADES systems significantly disrupt the microstructure of the solvent or the stability of the CALB enzyme within the time scales of the simula-tions. The enzyme preserves its initial structure, size and intra-chain hydrogen bonds in all investigated compositions and, for the first time reported, also in NADES with increased hydrogen bond donating com-pound ratios. As the main novelty, our results indicate that, in addition to the composition, the molar ratio can be an additional variable to fine-tune the physicochemical properties of NADES without altering the enzyme characteristics. These findings could facilitate the development and application of task -tailored NADES media for biocatalytic processes. (c) 2022 Elsevier B.V. All rights reserved.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000865431800010 Publication Date 2022-08-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0167-7322 ISBN Additional Links UA library record; WoS full record
Impact Factor 6 Times cited Open Access Not_Open_Access
Notes Approved Most recent IF: 6
Call Number UA @ admin @ c:irua:191538 Serial 7265
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Author Kovács, A.; Janssens, N.; Mielants, M.; Cornet, I.; Neyts, E.C.; Billen, P.
Title Biocatalyzed vinyl laurate transesterification in natural deep eutectic solvents Type A1 Journal article
Year 2023 Publication Waste and biomass valorization Abbreviated Journal
Volume Issue Pages 1-12
Keywords (up) A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT); Biochemical Wastewater Valorization & Engineering (BioWaVE); Intelligence in PRocesses, Advanced Catalysts and Solvents (iPRACS)
Abstract Purpose Natural deep eutectic solvents (NADES) represent a green alternative to conventional organic solvents as reaction medium, offering more benign properties. To efficiently design NADES for biocatalysis, a better understanding of their effect on these reactions is needed. We hypothesize that this effect can be described by separately considering (1) the solvent interactions with the substrates, (2) the solvent viscosities and (3) the enzyme stability in NADES. Methods We investigated the effect of substrate solvation and viscosity on the reaction rate; and the stability of the enzyme in NADES. To this end, we monitored the conversion over time of the transesterification of vinyl laurate with 1- butanol by the lipase enzyme Candida antarctica B in NADES of different compounds and molar ratios. Results The initial reaction rate is higher in most NADES ( varying between 1.14 and 15.07 mu mol min(-1) mg(-1)) than in the reference n-hexane (4.0 mu mol min(-1) mg(-1))), but no clear relationship between viscosity and initial reaction rate was found. The increased reaction rate is most likely related to the solvation of the substrate due to a change in the activation energy of the reaction or a change in the conformation of the substrate. The enzyme retained part of its activity after the first 2 h of reaction (on average 20 % of the substrate reacted in the 2-24 h period). Enzyme incubation in ethylene glycol-based NADES resulted in a reduced reaction rate ( 15.07 vs. 3.34 mu mol min(-1) mg(-1)), but this may also be due to slow dissolution of the substrate. Conclusions The effect of viscosity seems to be marginal next to the effect of solvation and possible enzyme-NADES interaction. The enzyme retains some of its activity during the 24-hour measurements, but the enzyme incubation experiments did not yield accurate, comparable values. [GRAPHICS] .
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 001117290800003 Publication Date 2023-12-07
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1877-2641; 1877-265x ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.2 Times cited Open Access
Notes Approved Most recent IF: 3.2; 2023 IF: 1.337
Call Number UA @ admin @ c:irua:202709 Serial 9005
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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 5 Pages 054002-54019
Keywords (up) A1 Journal article; Plasma, laser ablation and surface modeling – Antwerp (PLASMANT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication London Editor
Language Wos Publication Date 0000-00-00
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0022-3727 ISBN Additional Links UA library record
Impact Factor 2.588 Times cited Open Access
Notes Approved Most recent IF: 2.588
Call Number UA @ lucian @ c:irua:129798 Serial 4467
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Author Huygh, S.; Bogaerts, A.; Bal, K.M.; Neyts, E.C.
Title High Coke Resistance of a TiO2Anatase (001) Catalyst Surface during Dry Reforming of Methane Type A1 Journal Article
Year 2018 Publication Journal Of Physical Chemistry C Abbreviated Journal J Phys Chem C
Volume 122 Issue 17 Pages 9389-9396
Keywords (up) A1 Journal Article; Plasma, laser ablation and surface modeling Antwerp (PLASMANT) ;
Abstract The resistance of a TiO2 anatase (001) surface to coke formation was studied in the context of dry reforming of methane using density functional theory (DFT) calculations. As carbon atoms act as precursors for coke formation, the resistance to coke formation can be measured by the carbon coverage of the surface. This is related to the stability of different CHx (x = 0−3) species and their rate of hydrogenation and dehydrogenation on the TiO2 surface. Therefore, we studied the reaction mechanisms and their corresponding rates as a function of the temperature for the dehydrogenation of the species on the surface. We found that the stabilities of C and CH are significantly lower than those of CH3 and CH2. The hydrogenation rates of the different species are significantly higher than the dehydrogenation rates in a temperature range of 300−1000 K. Furthermore, we found that dehydrogenation of CH3, CH2, and CH will only occur at appreciable rates starting from 600, 900, and 900 K, respectively. On the basis of these results, it is clear that the anatase (001) surface has a high coke resistance, and it is thus not likely that the surface will become poisoned by coke during dry reforming of methane. As the rate limiting step in dry reforming is the dissociative adsorption of CH4, we studied an alternative approach to thermal catalysis. We found that the temperature threshold for dry reforming is at least 700 K. This threshold temperature may be lowered by the use of plasma-catalysis, where the appreciable rates of adsorption of plasma-generated CHx radicals result in bypassing the rate limiting step of the reaction.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000431723700014 Publication Date 2018-05-03
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1932-7447 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.536 Times cited 1 Open Access OpenAccess
Notes Federaal Wetenschapsbeleid, IAP/7 ; Fonds Wetenschappelijk Onderzoek, G.0217.14N ; Onderzoeksfonds, Universiteit Antwerpen, 32249 ; Approved Most recent IF: 4.536
Call Number PLASMANT @ plasmant @c:irua:151529c:irua:152816 Serial 5000
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Author 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 (up) 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.
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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 Most recent IF: 7.367; 2014 IF: 7.394
Call Number UA @ lucian @ c:irua:119408 Serial 3636
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Author Engelmann, Y.; van ’t Veer, K.; Gorbanev, Y.; Neyts, E.C.; Schneider, W.F.; Bogaerts, A.
Title Plasma Catalysis for Ammonia Synthesis: A Microkinetic Modeling Study on the Contributions of Eley–Rideal Reactions Type A1 Journal Article;Plasma catalysis
Year 2021 Publication Acs Sustainable Chemistry & Engineering Abbreviated Journal Acs Sustain Chem Eng
Volume 9 Issue 39 Pages 13151-13163
Keywords (up) A1 Journal Article;Plasma catalysis; Eley−Rideal reactions; Volcano plots; Vibrational excitation; Radical reactions; Dielectric barrier discharge; Plasma, laser ablation and surface modeling Antwerp (PLASMANT) ;
Abstract Plasma catalysis is an emerging new technology for the electrification and downscaling of NH3 synthesis. Increasing attention is being paid to the optimization of plasma catalysis with respect to the plasma conditions, the catalyst material, and their mutual interaction. In this work we use microkinetic models to study how the total conversion process is impacted by the combination of different plasma conditions and transition metal catalysts. We study how plasma-generated radicals and vibrationally excited N2 (present in a dielectric barrier discharge plasma) interact with the catalyst and impact the NH3 turnover frequencies (TOFs). Both filamentary and uniform plasmas are studied, based on plasma chemistry models that provided plasma phase speciation and vibrational distribution functions. The Langmuir−Hinshelwood reaction rate coefficients (i.e., adsorption reactions and subsequent reactions among adsorbates) are determined using conventional scaling relations. An additional set of Eley−Rideal reactions (i.e., direct reactions of plasma radicals with adsorbates) was added and a sensitivity analysis on the assumed reaction rate coefficients was performed. We first show the impact of different vibrational distribution functions on the catalytic dissociation of N2 and subsequent production of NH3, and we gradually include more radical reactions, to illustrate the contribution of these species and their corresponding reaction pathways. Analysis over a large range of catalysts indicates that different transition metals (metals such as Rh, Ni, Pt, and Pd) optimize the NH3TOFs depending on the population of the vibrational levels of N2. At higher concentrations of plasma-generated radicals, the NH3 TOFs become less dependent on the catalyst material, due to radical adsorptions on the more noble catalysts and Eley−Rideal reactions on the less noble catalysts.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000705367800004 Publication Date 2021-10-04
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 5.951 Times cited Open Access OpenAccess
Notes Basic Energy Sciences, DE-SC0021107 ; Vlaamse regering, HBC.2019.0108 ; H2020 European Research Council, 810182 ; Methusalem project – University of Antwerp; Excellence of science FWO-FNRS, GoF9618n ; TOP-BOF – University of Antwerp; DOCPRO3 – University of Antwerp; We acknowledge the financial support from the DOC-PRO3, the TOP-BOF, and the Methusalem project of the University of Antwerp, as well as from the European Research Council (ERC) (grant agreement No, 810182−SCOPE ERC Synergy project), under the European Union’s Horizon 2020 research and innovation programme, the Flemish Government through the Moonshot cSBO project P2C (HBC.2019.0108), and the Excellence of Science FWO-FNRS project (FWO grant ID GoF9618n, EOS ID 30505023). Calculations were carried out using the Turing HPC infrastructure at the CalcUA core facility of the Universiteit Antwerpen, a division of the Flemish Supercomputer Center VSC, funded by the Hercules Foundation, the Flemish Government (Department EWI), 13162 Approved Most recent IF: 5.951
Call Number PLASMANT @ plasmant @c:irua:182482 Serial 6811
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Author Bal, K.M.; Neyts, E.C.
Title Quantifying the impact of vibrational nonequilibrium in plasma catalysis: insights from a molecular dynamics model of dissociative chemisorption Type A1 Journal Article;plasma catalysis
Year 2021 Publication Journal Of Physics D-Applied Physics Abbreviated Journal J Phys D Appl Phys
Volume 54 Issue 39 Pages 394004
Keywords (up) A1 Journal Article;plasma catalysis; vibrational nonequilibrium; dissociative chemisorption; free energy barriers; Plasma, laser ablation and surface modeling Antwerp (PLASMANT) ;
Abstract The rate, selectivity and efficiency of plasma-based conversion processes is strongly affected by nonequilibrium phenomena. High concentrations of vibrationally excited molecules are such a plasma-induced effect. It is frequently assumed that vibrationally excited molecules are important in plasma catalysis because their presence lowers the apparent activation energy of dissociative chemisorption reactions and thus increases the conversion rate. A detailed atomic-level understanding of vibrationally stimulated catalytic reactions in the context of plasma catalysis is however lacking. Here, we couple a recently developed statistical model of a plasma-induced vibrational nonequilibrium to molecular dynamics simulations, enhanced sampling methods, and machine learning techniques. We quantify the impact of a vibrational nonequilibrium on the dissociative chemisorption barrier of H2 and CH4 on nickel catalysts over a wide range of vibrational temperatures. We investigate the effect of surface structure and compare the role of different vibrational modes of methane in the dissociation process. For low vibrational temperatures, very high vibrational efficacies are found, and energy in bend vibrations appears to dominate the dissociation of methane. The relative impact of vibrational nonequilibrium is much higher on terrace sites than on surface steps. We then show how our simulations can help to interpret recent experimental results, and suggest new paths to a better understanding of plasma catalysis.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000674464100001 Publication Date 2021-09-30
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 Open Access OpenAccess
Notes Fonds Wetenschappelijk Onderzoek, 12ZI420N ; K M B was funded as a junior postdoctoral fellow of the FWO (Research Foundation—Flanders), Grant 12ZI420N. The computational resources and services used in this work were provided by the HPC core facility CalcUA of the Universiteit Antwerpen, and VSC (Flemish Supercomputer Center), funded by the FWO and the Flemish Government. HLDA calculations were performed with a script provided by G Piccini. Approved Most recent IF: 2.588
Call Number PLASMANT @ plasmant @c:irua:179830 Serial 6808
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