|
“On the c-Si\mid a-SiO2 interface in hyperthermal Si oxidation at room temperature”. Khalilov U, Pourtois G, van Duin ACT, Neyts EC, The journal of physical chemistry: C : nanomaterials and interfaces 116, 21856 (2012). http://doi.org/10.1021/jp306920p
Abstract: The exact structure and properties of the Si vertical bar SiO2 interface are very important in microelectronics and photovoltaic devices such as metal-oxide-semiconductor field-effect transistors (MOSFETs) and solar cells. Whereas Si vertical bar SiO2 structures are traditionally produced by thermal oxidation, hyperthermal oxidation shows a number of promising advantages. However, the Si vertical bar SiO2 interface induced in hyperthermal Si oxidation has not been properly investigated yet. Therefore, in this work, the interface morphology and interfacial stresses during hyperthermal oxidation at room temperature are studied using reactive molecular dynamics simulations based on the ReaxFF potential. Interface thickness and roughness, as well as the bond length and bond angle distributions in the interface are discussed and compared with other models developed for the interfaces induced by traditional thermal oxidation. The formation of a compressive stress is observed. This compressive stress, which at the interface amounts about 2 GPa, significantly slows down the inward silica growth. This value is close to the experimental value in the Si vertical bar SiO2 interface obtained in traditional thermal oxidation.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.536
Times cited: 27
DOI: 10.1021/jp306920p
|
|
|
“The Dominant Pathways for the Conversion of Methane into Oxygenates and Syngas in an Atmospheric Pressure Dielectric Barrier Discharge”. De Bie C, van Dijk J, Bogaerts A, The journal of physical chemistry: C : nanomaterials and interfaces 119, 22331 (2015). http://doi.org/10.1021/acs.jpcc.5b06515
Abstract: A one-dimensional fluid model for a dielectric barrier discharge in CH4/O2 and CH4/CO2 gas mixtures is developed. The model describes the gas-phase chemistry for partial oxidation and for dry reforming of methane. The spatially averaged densities of the various plasma species are presented as a function of time and initial gas mixing ratio. Besides, the conversion of the inlet gases and the selectivities of the reaction products are calculated. Syngas, higher hydrocarbons, and higher oxygenates are typically found to be important reaction products. Furthermore, the main underlying reaction pathways for the formation of syngas, methanol, formaldehyde, and other higher oxygenates are determined.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.536
Times cited: 46
DOI: 10.1021/acs.jpcc.5b06515
|
|
|
“Plasma-based dry reforming : a computational study ranging from the nanoseconds to seconds time scale”. Snoeckx R, Aerts R, Tu X, Bogaerts A, The journal of physical chemistry: C : nanomaterials and interfaces 117, 4957 (2013). http://doi.org/10.1021/jp311912b
Abstract: We present a computational study for the conversion of CH4 and CO2 into value-added chemicals, i.e., the so-called dry reforming of methane, in a dielectric barrier discharge reactor. A zero-dimensional chemical kinetics model is applied to study the plasma chemistry in a 1:1 CH4/CO2 mixture. The calculations are first performed for one microdischarge pulse and its afterglow, to study in detail the chemical pathways of the conversion. Subsequently, long time-scale simulations are carried out, corresponding to real residence times in the plasma, assuming a large number of consecutive microdischarge pulses, to mimic the conditions of the filamentary discharge regime in a dielectric barrier discharge (DBD) reactor. The conversion of CH4 and CO2 as well as the selectivity of the formed products and the energy cost and energy efficiency of the process are calculated and compared to experiments for a range of different powers and gas flows, and reasonable agreement is reached.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.536
Times cited: 118
DOI: 10.1021/jp311912b
|
|
|
“Plasma-induced destruction of bacterial cell wall components : a reactive molecular dynamics simulation”. Yusupov M, Bogaerts A, Huygh S, Snoeckx R, van Duin ACT, Neyts EC, The journal of physical chemistry: C : nanomaterials and interfaces 117, 5993 (2013). http://doi.org/10.1021/jp3128516
Abstract: Nonthermal atmospheric pressure plasmas are gaining increasing attention for biomedical applications. However, very little fundamental information on the interaction mechanisms between the plasma species and biological cells is currently available. We investigate the interaction of important plasma species, such as OH, H2O2, O, O3, as well as O2 and H2O, with bacterial peptidoglycan by means of reactive molecular dynamics simulations, aiming for a better understanding of plasma disinfection. Our results show that OH, O, O3, and H2O2 can break structurally important bonds of peptidoglycan (i.e., CO, CN, or CC bonds), which consequently leads to the destruction of the bacterial cell wall. The mechanisms behind these breakups are, however, dependent on the impinging plasma species, and this also determines the effectiveness of the cell wall destruction.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.536
Times cited: 59
DOI: 10.1021/jp3128516
|
|
|
“Plasma species interacting with nickel surfaces : toward an atomic scale understanding of plasma-catalysis”. Somers W, Bogaerts A, van Duin ACT, Neyts EC, The journal of physical chemistry: C : nanomaterials and interfaces 116, 20958 (2012). http://doi.org/10.1021/jp307380w
Abstract: The adsorption probability and reaction behavior of CHx plasma species on various nickel catalyst surfaces is investigated by means of reactive molecular dynamics (MD) simulations using the ReaxFF potential. Such catalysts are used in the reforming of hydrocarbons and in the growth of carbon nanotubes, and further insight in the underlying mechanisms of these processes is needed to increase their applicability. Single and consecutive impacts of CHx radicals (x={1,2,3}) were performed on four different Ni surfaces, at a temperature of 400 K. The adsorption probability is shown to be related to the number of free electrons, i.e. a higher number leads to more adsorptions, and the steric hindrance caused by the hydrogen atoms bonded to the impacting CHx species. Furthermore, some of the CH bonds break after adsorption, which generally leads to diffusion of the hydrogen atom over the surface. Additionally, these adsorbed H-atoms can be used in reactions to form new molecules, such as CH4 and C2Hx, although this is dependent on the precise morphology of the surface. New molecules are also formed by subtraction of H-atoms from adsorbed radicals, leading to occasional formation of H2 and C2Hx molecules.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.536
Times cited: 37
DOI: 10.1021/jp307380w
|
|
|
“CO2 conversion in a microwave plasma reactor in the presence of N2 : elucidating the role of vibrational levels”. Heijkers S, Snoeckx R, Kozák T, Silva T, Godfroid T, Britun N, Snyders R, Bogaerts A, The journal of physical chemistry: C : nanomaterials and interfaces 119, 12815 (2015). http://doi.org/10.1021/acs.jpcc.5b01466
Abstract: A chemical kinetics model is developed for a CO2/N2 microwave plasma, focusing especially on the vibrational levels of both CO2 and N2. The model is used to calculate the CO2 and N2 conversion as well as the energy efficiency of CO2 conversion for different power densities and for N2 fractions in the CO2/N2 gas mixture ranging from 0 to 90%. The calculation results are compared with measurements, and agreements within 23% and 33% are generally found for the CO2 conversion and N2 conversion, respectively. To explain the observed trends, the destruction and formation processes of both CO2 and N2 are analyzed, as well as the vibrational distribution functions of both CO2 and N2. The results indicate that N2 contributes in populating the lower asymmetric levels of CO2, leading to a higher absolute CO2 conversion upon increasing N2 fraction. However, the effective CO2 conversion drops because there is less CO2 initially present in the gas mixture; thus, the energy efficiency also drops with rising N2 fraction.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.536
Times cited: 56
DOI: 10.1021/acs.jpcc.5b01466
|
|
|
“Selective Plasma Oxidation of Ultrasmall Si Nanowires”. Khalilov U, Yusupov M, Bogaerts A, Neyts EC, The journal of physical chemistry: C : nanomaterials and interfaces 120, 472 (2016). http://doi.org/10.1021/acs.jpcc.5b11027
Abstract: Device performance of Si|SiOx core-shell based nanowires critically depends on the exact control over the oxide thickness. Low-temperature plasma oxidation is a highly promising alternative to thermal oxidation allowing for improved control over the oxidation process, in particular for ultrasmall Si nanowires. We here elucidate the room temperature plasma oxidation mechanisms of ultrasmall Si nanowires using hybrid molecular dynamics / force-bias Monte Carlo simulations. We demonstrate how the oxidation and concurrent water formation mechanisms are a function of the oxidizing plasma species and we demonstrate how the resulting core-shell oxide thickness can be controlled through these species. A new mechanism of water formation is discussed in detail. The results provide a detailed atomic level explanation of the oxidation process of highly curved Si surfaces. These results point out a route toward plasma-based formation of ultrathin core-shell Si|SiOx nanowires at room temperature.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.536
Times cited: 3
DOI: 10.1021/acs.jpcc.5b11027
|
|
|
“How Oxygen Vacancies Activate CO2 Dissociation on TiO2 Anatase (001)”. Huygh S, Bogaerts A, Neyts EC, The journal of physical chemistry: C : nanomaterials and interfaces 120, 21659 (2016). http://doi.org/10.1021/acs.jpcc.6b07459
Abstract: The adsorption, dissociation, and diffusion of CO2 on the anatase (001) surface was studied using DFT by means of the generalized gradient approximation using the Perdew−Burcke−Ernzerhof (PBE)-functional and applying corrections for long-range dispersion interactions. Different stable adsorption configurations were identified for the fully oxidized surface. The most stable adsorption configuration is the monodentated carbonate-like structure. Small energy barriers were identified for the conversion of a physisorbed to a chemisorbed configuration.
CO2 dissociation is found to be unfeasible on the stoichiometric surface. The introduction of oxygen vacancy defects gives rise to new highly stable adsorption configurations with a stronger activation of the C−O bonds. This leads to the possibility of exothermic dissociation of CO2 with barriers up to 22.2 kcal/mol,
corresponding to chemical lifetimes of less than 4 s at 300 K. These reactions cause a CO molecule to be formed, which will easily desorb, and the reduced surface to become oxidized. It is clear that oxygen vacancy defects play a key role in the catalytic activity of an anatase (001) surface. Oxygen vacancies play an important role in the dissociation of CO2 on the anatase (001) surface, and will play a significant role in complex problems, such as the catalytic conversion of CO2 to value-added chemicals.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.536
Times cited: 49
DOI: 10.1021/acs.jpcc.6b07459
|
|
|
“CO2Hydrogenation in a Dielectric Barrier Discharge Plasma Revealed”. De Bie C, van Dijk J, Bogaerts A, The journal of physical chemistry: C : nanomaterials and interfaces 120, 25210 (2016). http://doi.org/10.1021/acs.jpcc.6b07639
Abstract: The hydrogenation of carbon dioxide in a dielectric barrier discharge plasma is studied with a one-dimensional fluid model. The spatially averaged densities of the most important end products formed in the CO2/H2 mixture are determined as a function of the initial gas mixing ratio. CO and H2O are found to be present at the highest densities and to a lower content also CH4, C2H6, CH2O, CH3OH, O2, and some other higher hydrocarbons and oxygenates. The main underlying reaction
pathways for the conversion of the inlet gases and the formation of CO, CH4, CH2O, and CH3OH are pointed out for various gas mixing ratios. The CO2 conversion and the production of value added products is found to be quite low, also in comparison to a CO2/CH4 mixture, and this can be explained by the model.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.536
Times cited: 16
DOI: 10.1021/acs.jpcc.6b07639
|
|
|
“Mechanisms of Peptide Oxidation by Hydroxyl Radicals: Insight at the Molecular Scale”. Verlackt CCW, Van Boxem W, Dewaele D, Lemière F, Sobott F, Benedikt J, Neyts EC, Bogaerts A, The journal of physical chemistry: C : nanomaterials and interfaces 121, 5787 (2017). http://doi.org/10.1021/acs.jpcc.6b12278
Abstract: Molecular dynamics (MD) simulations were performed to provide atomic scale insight in the initial interaction between hydroxyl radicals (OH) and peptide systems in solution. These OH radicals are representative reactive oxygen species produced by cold atmospheric plasmas. The use of plasma for biomedical applications is gaining increasing interest, but the fundamental mechanisms behind the plasma modifications still remain largely elusive. This study helps to gain more insight in the underlying mechanisms of plasma medicine but is also more generally applicable to peptide oxidation, of interest for other applications. Combining both reactive and nonreactive MD simulations, we are able to elucidate the reactivity of the amino acids inside the peptide systems and their effect on their structure up to 1 μs. Additionally, experiments were performed, treating the simulated peptides with a plasma jet. The computational results presented here correlate well with the obtained experimental data and highlight the importance of the chemical environment for the reactivity of the individual amino acids, so that specific amino acids are attacked in higher numbers than expected. Furthermore, the long time scale simulations suggest that a single oxidation has an effect on the 3D conformation due to an increase in hydrophilicity and intra- and intermolecular interactions.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.536
Times cited: 5
DOI: 10.1021/acs.jpcc.6b12278
|
|
|
“Toward an understanding of the electric field-induced electrostatic doping in van der Waals heterostructures : a first-principles study”. Lu AKA, Houssa M, Radu IP, Pourtois G, ACS applied materials and interfaces 9, 7725 (2017). http://doi.org/10.1021/ACSAMI.6B14722
Abstract: Since the discovery of graphene, a broad range of two-dimensional (2D) materials has captured the attention of the scientific communities. Materials, such as hexagonal boron nitride (hBN) and the transition metal dichalcogenides (TMDs) family, have shown promising semiconducting and insulating properties that are very appealing for the semiconductor industry. Recently, the possibility of taking advantage of the properties of 2D-based heterostructures has been investigated for low-power nanoelectronic applications. In this work, we aim at evaluating the relation between the nature of the materials used in such heterostructures and the amplitude of the layer-to-layer charge transfer induced by an external electric field, as is typically present in nanoelectronic gated devices. A broad range of combinations of TMDs, graphene, and hBN has been investigated using density functional theory. Our results show that the electric field induced charge transfer strongly depends on the nature of the 2D materials used in the van der Waals heterostructures and to a lesser extent on the relative orientation of the materials in the structure. Our findings contribute to the building of the fundamental understanding required to engineer electrostatically the doping of 2D materials and to establish the factors that drive the charge transfer mechanisms in electron tunneling-based devices. These are key ingredients for the development of 2D -based nanoelectronic devices.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 7.504
Times cited: 10
DOI: 10.1021/ACSAMI.6B14722
|
|
|
“Density functional theory study of interface interactions in hydroxyapatite/rutile composites for biomedical applications”. Grubova IY, Surmeneva MA, Huygh S, Surmenev RA, Neyts EC, The journal of physical chemistry: C : nanomaterials and interfaces 121, 15687 (2017). http://doi.org/10.1021/ACS.JPCC.7B02926
Abstract: To gain insight into the nature of the adhesion mechanism between hydroxyapatite (HA) and rutile (rTiO(2)), the mutual affinity between their surfaces was systematically studied using density functional theory (DFT). We calculated both bulk and surface properties of HA and rTiO(2), and explored the interfacial bonding mechanism of amorphous HA (aHA) surface onto amorphous as well as stoichiometric and nonstoichiometric crystalline rTiO(2). Formation energies of bridging and subbridging oxygen vacancies considered in the rTiO(2)(110) surface were evaluated and compared with other theoretical and experimental results. The interfacial interaction was evaluated through the work of adhesion. For the aHA/rTiO(2)(110) interfaces, the work of adhesion is found to depend strongly on the chemical environment of the rTiO(2)(110) surface. Electronic analysis indicates that the charge transfer is very small in the case of interface formation between aHA and crystalline rTiO(2)(110). In contrast, significant charge transfer occurs between aHA and amorphous rTiO(2) (aTiO(2)) slabs during the formation of the interface. Charge density difference (CDD) analysis indicates that the dominant interactions in the interface have significant covalent character, and in particular the Ti-O and Ca-O bonds. Thus, the obtained results reveal that the aHA/aTiO(2) interface shows a more preferable interaction and is thermodynamically more stable than other interfaces. These results are particularly important for improving the long-term stability of HA-based implants.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.536
Times cited: 5
DOI: 10.1021/ACS.JPCC.7B02926
|
|
|
“Stabilities of bimetallic nanoparticles for chirality-selective carbon nanotube growth and the effect of carbon interstitials”. Vets C, Neyts EC, The journal of physical chemistry: C : nanomaterials and interfaces 121, 15430 (2017). http://doi.org/10.1021/ACS.JPCC.7B02880
Abstract: Bimetallic nanoparticles play a crucial role in various applications. A better understanding of their properties would facilitate these applications and possibly even enable chirality-specific growth of carbon nanotubes (CNTs). We here examine the stabilities of NiFe, NiGa, and FeGa nanoparticles and the effect of carbon dissolved in NiFe nanoparticles through density functional theory (DFT) calculations and Born Oppenheimer molecular dynamics (BOMD) simulations. We establish that nanoparticles with more Fe in the core and more Ga on the surface are more stable and compare these results with well-known properties such as surface energy and atom size. Furthermore, we find that the nanoparticles become more stable with increasing carbon content, both at 0 K and at 700 K. These results provide a basis for further research into the chirality-specific growth of CNT's.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.536
Times cited: 2
DOI: 10.1021/ACS.JPCC.7B02880
|
|
|
“CO2Conversion in a Gliding Arc Plasmatron: Elucidating the Chemistry through Kinetic Modeling”. Heijkers S, Bogaerts A, The journal of physical chemistry: C : nanomaterials and interfaces 121, 22644 (2017). http://doi.org/10.1021/acs.jpcc.7b06524
Abstract: By means of chemical kinetics modeling, it is possible to elucidate the main dissociation mechanisms of CO2 in a gliding arc plasmatron (GAP). We obtain good agreement between the calculated and experimental conversions and energy efficiencies, indicating that the model can indeed be used to study the underlying mechanisms. The calculations predict that vibration-induced dissociation is the main dissociation mechanism of CO2, but it occurs mainly from the lowest vibrational levels because of fast thermalization of the vibrational distribution. Based on these findings, we propose ideas for improving the performance of the GAP, but testing of these ideas in the simulations reveals that they do not always lead to significant enhancement, because of other side effects, thus illustrating the complexity of the process. Nevertheless, the model allows more insight into the underlying mechanisms to be obtained and limitations to be identified.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.536
Times cited: 6
DOI: 10.1021/acs.jpcc.7b06524
|
|
|
“Modeling Plasma-based CO2and CH4Conversion in Mixtures with N2, O2, and H2O: The Bigger Plasma Chemistry Picture”. Wang W, Snoeckx R, Zhang X, Cha MS, Bogaerts A, The journal of physical chemistry: C : nanomaterials and interfaces 122, 8704 (2018). http://doi.org/10.1021/acs.jpcc.7b10619
Abstract: Because of the unique properties of plasma technology, its use in gas conversion applications is gaining significant interest around the globe. Plasma-based CO2 and CH4 conversion has become a major research area. Many investigations have already been performed regarding the single-component gases, that is, CO2 splitting and CH4 reforming, as well as for two-component mixtures, that is, dry reforming of methane
(CO2/CH4), partial oxidation of methane (CH4/O2), artificial photosynthesis (CO2/H2O), CO2 hydrogenation (CO2/H2), and even first steps toward the influence of N2 impurities have been taken, that is, CO2/N2 and CH4/N2. In this Feature Article we briefly discuss the advances made in literature for these different steps from a plasma chemistry modeling point of view. Subsequently, we present a comprehensive plasma chemistry set, combining the knowledge gathered in this field so far and supported with extensive experimental data. This set can be used for chemical kinetics plasma modeling for all possible combinations of CO2, CH4, N2, O2, and H2O to investigate the bigger picture of the underlying plasmachemical pathways for these mixtures in a dielectric barrier discharge plasma. This is extremely valuable
for the optimization of existing plasma-based CO2 conversion and CH4 reforming processes as well as for investigating the influence of N2, O2, and H2O on these processes and even to support plasma-based multireforming processes.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.536
Times cited: 28
DOI: 10.1021/acs.jpcc.7b10619
|
|
|
“Overcoming Old Scaling Relations and Establishing New Correlations in Catalytic Surface Chemistry: Combined Effect of Charging and Doping”. Bal KM, Neyts EC, The journal of physical chemistry: C : nanomaterials and interfaces 123, 6141 (2019). http://doi.org/10.1021/acs.jpcc.9b01216
Abstract: Optimization of catalytic materials for a given application is greatly constrained by linear scaling relations. Recently, however, it has been demonstrated that it is possible to reversibly modulate the chemisorption of molecules on nanomaterials by charging (i.e., injection or removal of electrons) and hence reversibly and selectively modify catalytic activity beyond structure−activity correlations. The fundamental physical relation between the properties of the material, the charging process, and the chemisorption energy, however, remains unclear, and a systematic exploration and optimization of charge-switchable sorbent materials is not yet possible. Using hybrid DFT calculations of CO2 chemisorption on hexagonal boron nitride nanosheets with several types of defects and dopants, we here reveal the existence of fundamental correlations between the electron affinity of a material and charge-induced chemisorption, show how defect engineering can be used to modulate the strength and efficiency of the adsorption process, and demonstrate that excess electrons stabilize many topological defects. We then show how these insights could be exploited in the development of new electrocatalytic materials and the synthesis of doped nanomaterials. Moreover, we demonstrate that calculated chemical properties of charged materials are highly sensitive to the employed computational methodology because of the self-interaction error, which underlines the theoretical challenge posed by such systems.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.536
Times cited: 5
DOI: 10.1021/acs.jpcc.9b01216
|
|
|
“Nanosecond Pulsed Discharge for CO2Conversion: Kinetic Modeling To Elucidate the Chemistry and Improve the Performance”. Heijkers S, Martini LM, Dilecce G, Tosi P, Bogaerts A, The journal of physical chemistry: C : nanomaterials and interfaces 123, 12104 (2019). http://doi.org/10.1021/acs.jpcc.9b01543
Abstract: We study the mechanisms of CO2 conversion in a nanosecond repetitively pulsed (NRP) discharge, by means of a chemical kinetics model. The calculated conversions and energy efficiencies are in reasonable agreement with experimental results over a wide range of specific energy input values, and the same applies to the evolution of gas temperature and CO2 conversion as a function of time in the afterglow, indicating that our model provides a realistic picture of the underlying mechanisms in the NRP discharge and can be used to identify its limitations and thus to suggest further improvements. Our model predicts that vibrational excitation is very important in the NRP discharge, explaining why this type of plasma yields energy-efficient CO2 conversion. A significant part of the CO2 dissociation occurs by electronic excitation from the lower vibrational levels toward repulsive electronic states, thus resulting in dissociation. However, vibration−translation (VT) relaxation (depopulating the higher vibrational levels) and CO + O recombination (CO + O + M → CO2 + M), as well as mixing of the converted gas with fresh gas entering the plasma in between the pulses, are limiting factors for the conversion and energy efficiency. Our model predicts that extra cooling, slowing down the rate of VT relaxation and of the above recombination reaction, thus enhancing the contribution of the highest vibrational levels to the overall CO2 dissociation, can further improve the performance of the NRP discharge for energy-efficient CO2 conversion.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.536
Times cited: 4
DOI: 10.1021/acs.jpcc.9b01543
|
|
|
“CO2 activation on TiO2-supported Cu5 and Ni5 nanoclusters : effect of plasma-induced surface charging”. Jafarzadeh A, Bal KM, Bogaerts A, Neyts EC, The journal of physical chemistry: C : nanomaterials and interfaces 123, 6516 (2019). http://doi.org/10.1021/ACS.JPCC.8B11816
Abstract: Surface charging is an often overlooked factor in many plasma-surface interactions and in particular in plasma catalysis. In this study, we investigate the effect of excess electrons induced by a plasma on the adsorption properties of CO2 on titania-supported Cu-5 and Ni-5 clusters using spin-polarized and dispersion-corrected density functional theory calculations. The effect of excess electrons on the adsorption of Ni and Cu pentamers as well as on CO2 adsorption on a pristine anatase TiO2(101) slab is studied. Our results indicate that adding plasma-induced excess electrons to the system leads to further stabilization of the bent CO2 structure. Also, dissociation of CO2 on charged clusters is energetically more favorable than on neutral clusters. We hypothesize that surface charge is a plausible cause for the synergistic effects sometimes observed in plasma catalysis.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.536
Times cited: 4
DOI: 10.1021/ACS.JPCC.8B11816
|
|
|
“Improving the Energy Efficiency of CO2Conversion in Nonequilibrium Plasmas through Pulsing”. Vermeiren V, Bogaerts A, The journal of physical chemistry: C : nanomaterials and interfaces 123, 17650 (2019). http://doi.org/10.1021/acs.jpcc.9b02362
Abstract: Nonequilibrium plasmas offer a pathway for energy-efficient CO2 conversion through vibrationally induced dissociation. However, the efficiency of this pathway is limited by a rise in gas temperature, which increases vibrational−translational (VT) relaxation and quenches the vibrational levels. Therefore, we investigate here the effect of plasma pulsing on the VT nonequilibrium and on the CO2 conversion by means of a zerodimensional chemical kinetics model, with self-consistent gas temperature calculation. Specifically, we show that higher energy efficiencies can be reached by correctly tuning the plasma pulse and interpulse times. The ideal plasma pulse time corresponds to the time needed to reach the highest vibrational temperature. In addition, the highest energy efficiencies are obtained with long interpulse times, that is, ≥0.1 s, in which the gas temperature can entirely drop to room temperature. Furthermore, additional cooling of the reactor walls can give higher energy efficiencies at shorter interpulse times of 1 ms. Finally, our model shows that plasma pulsing can significantly improve the energy efficiency at low reduced electric fields (50 and 100 Td, typical for microwave and gliding arc plasmas) and intermediate ionization degrees (5 × 10−7 and 10−6).
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.536
Times cited: 1
DOI: 10.1021/acs.jpcc.9b02362
|
|
|
“Reactive plasma cleaning and restoration of transition metal dichalcogenide monolayers”. Marinov D, de Marneffe J-F, Smets Q, Arutchelvan G, Bal KM, Voronina E, Rakhimova T, Mankelevich Y, El Kazzi S, Nalin Mehta A, Wyndaele P-J, Heyne MH, Zhang J, With PC, Banerjee S, Neyts EC, Asselberghs I, Lin D, De Gendt S, npj 2D Materials and Applications 5, 17 (2021). http://doi.org/10.1038/s41699-020-00197-7
Abstract: The cleaning of two-dimensional (2D) materials is an essential step in the fabrication of future devices, leveraging their unique physical, optical, and chemical properties. Part of these emerging 2D materials are transition metal dichalcogenides (TMDs). So far there is limited understanding of the cleaning of “monolayer” TMD materials. In this study, we report on the use of downstream H<sub>2</sub>plasma to clean the surface of monolayer WS<sub>2</sub>grown by MOCVD. We demonstrate that high-temperature processing is essential, allowing to maximize the removal rate of polymers and to mitigate damage caused to the WS<sub>2</sub>in the form of sulfur vacancies. We show that low temperature in situ carbonyl sulfide (OCS) soak is an efficient way to resulfurize the material, besides high-temperature H<sub>2</sub>S annealing. The cleaning processes and mechanisms elucidated in this work are tested on back-gated field-effect transistors, confirming that transport properties of WS<sub>2</sub>devices can be maintained by the combination of H<sub>2</sub>plasma cleaning and OCS restoration. The low-damage plasma cleaning based on H<sub>2</sub>and OCS is very reproducible, fast (completed in a few minutes) and uses a 300 mm industrial plasma etch system qualified for standard semiconductor pilot production. This process is, therefore, expected to enable the industrial scale-up of 2D-based devices, co-integrated with silicon technology.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
DOI: 10.1038/s41699-020-00197-7
|
|
|
“Possible Synergies of Nanomaterial-Assisted Tissue Regeneration in Plasma Medicine: Mechanisms and Safety Concerns”. Shaw P, Vanraes P, Kumar N, Bogaerts A, Nanomaterials 12, 3397 (2022). http://doi.org/10.3390/nano12193397
Abstract: Cold atmospheric plasma and nanomedicine originally emerged as individual domains, but are increasingly applied in combination with each other. Most research is performed in the context of cancer treatment, with only little focus yet on the possible synergies. Many questions remain on the potential of this promising hybrid technology, particularly regarding regenerative medicine and tissue engineering. In this perspective article, we therefore start from the fundamental mechanisms in the individual technologies, in order to envision possible synergies for wound healing and tissue recovery, as well as research strategies to discover and optimize them. Among these strategies, we demonstrate how cold plasmas and nanomaterials can enhance each other’s strengths and overcome each other’s limitations. The parallels with cancer research, biotechnology and plasma surface modification further serve as inspiration for the envisioned synergies in tissue regeneration. The discovery and optimization of synergies may also be realized based on a profound understanding of the underlying redox- and field-related biological processes. Finally, we emphasize the toxicity concerns in plasma and nanomedicine, which may be partly remediated by their combination, but also partly amplified. A widespread use of standardized protocols and materials is therefore strongly recommended, to ensure both a fast and safe clinical implementation.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 5.3
DOI: 10.3390/nano12193397
|
|
|
“Bioactive Nonthermal Biocompatible Plasma Enhances Migration on Human Gingival Fibroblasts”. Han I, Song IS, Choi SA, Lee T, Yusupov M, Shaw P, Bogaerts A, Choi EH, Ryu JJ, Advanced healthcare materials 12, 2200527 (2023). http://doi.org/10.1002/adhm.202200527
Abstract: This study hypothesizes that the application of low-dose nonthermal biocompatible dielectric barrier discharge plasma (DBD-NBP) to human gingival fibroblasts (HGFs) will inhibit colony formation but not cell death and induce matrix metalloproteinase (MMP) expression, extracellular matrix (ECM) degradation, and subsequent cell migration, which can result in enhanced wound healing. HGFs treated with plasma for 3 min migrate to each other across the gap faster than those in the control and 5-min treatment groups on days 1 and 3. The plasma-treated HGFs show significantly high expression levels of the cell cycle arrest-related p21 gene and enhanced MMP activity. Focal adhesion kinase (FAK) mediated attenuation of wound healing or actin cytoskeleton rearrangement, and plasma-mediated reversal of this attenuation support the migratory effect of DBD-NBP. Further, this work performs computer simulations to investigate the effect of oxidation on the stability and conformation of the catalytic kinase domain (KD) of FAK. It is found that the oxidation of highly reactive amino acids (AAs) Cys427, Met442, Cys559, Met571, Met617, and Met643 changes the conformation and increases the structural flexibility of the FAK protein and thus modulates its function and activity. Low-dose DBD-NBP-induces host cell cycle arrest, ECM breakdown, and subsequent migration, thus contributing to the enhanced wound healing process.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 10
DOI: 10.1002/adhm.202200527
|
|
|
“Laurdan as a molecular rotor in biological environments”. Osella S, Knippenberg S, ACS applied bio materials 2, 5769 (2019). http://doi.org/10.1021/ACSABM.9B00789
Abstract: Laurdan is one of the most used fluorescent probes for lipid membrane phase recognition. Despite its wide use for optical techniques and its versatility as a solvatochromic probe, little is known regarding its use as molecular rotor, for which clear evidence is found in the current study. Although recent computational and experimental studies suggest the existence of two stable conformations of laurdan in different membrane phases, it is difficult to experimentally probe their prevalence. By means of multiscale computational approaches, we prove now that this information can be obtained through the optical properties of the two conformers, ranging from one-photon absorption over two-photon absorption to the first hyperpolarizability. Fluorescence decay and anisotropy analyses are performed as well and stress the importance of laurdan's conformational versatility. As a molecular rotor and with reference to the distinct properties of its conformers, laurdan can be used to probe biochemical processes that change the lipid orders in cell membranes.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
DOI: 10.1021/ACSABM.9B00789
|
|
|
“Linking bi-metal distribution patterns in porous carbon nitride fullerene to its catalytic activity toward gas adsorption”. Nematollahi P, Neyts EC, Nanomaterials 11, 1794 (2021). http://doi.org/10.3390/NANO11071794
Abstract: Immobilization of two single transition metal (TM) atoms on a substrate host opens numerous possibilities for catalyst design. If the substrate contains more than one vacancy site, the combination of TMs along with their distribution patterns becomes a design parameter potentially complementary to the substrate itself and the bi-metal composition. By means of DFT calculations, we modeled three dissimilar bi-metal atoms (Ti, Mn, and Cu) doped into the six porphyrin-like cavities of porous C24N24 fullerene, considering different bi-metal distribution patterns for each binary complex, viz. TixCuz@C24N24, TixMny@C24N24, and MnyCuz@C24N24 (with x, y, z = 0-6). We elucidate whether controlling the distribution of bi-metal atoms into the C24N24 cavities can alter their catalytic activity toward CO2, NO2, H-2, and N-2 gas capture. Interestingly, Ti2Mn4@C24N24 and Ti2Cu4@C24N24 complexes showed the highest activity and selectively toward gas capture. Our findings provide useful information for further design of novel few-atom carbon-nitride-based catalysts.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.553
DOI: 10.3390/NANO11071794
|
|
|
“Simulating highly activated sticking of H₂, on Al(110) : quantum versus quasi-classical dynamics”. Tchakoua T, Powell AD, Gerrits N, Somers MF, Doblhoff-Dier K, Busnengo HF, Kroes G-J, The journal of physical chemistry: C : nanomaterials and interfaces 127, 5395 (2023). http://doi.org/10.1021/ACS.JPCC.3C00426
Abstract: We evaluate the importance of quantum effects on the sticking of H2 on Al(110) for conditions that are close to those of molecular beam experiments that have been done on this system. Calculations with the quasi-classical trajectory (QCT) method and with quantum dynamics (QD) are performed using a model in which only motion in the six molecular degrees of freedom is allowed. The potential energy surface used has a minimum barrier height close to the value recently obtained with the quantum Monte Carlo method. Monte Carlo averaging over the initial rovibrational states allowed the QD calculations to be done with an order of magnitude smaller computational expense. The sticking probability curve computed with QD is shifted to lower energies relative to the QCT curve by 0.21 to 0.05 kcal/mol, with the highest shift obtained for the lowest incidence energy. Quantum effects are therefore expected to play a small role in calculations that would evaluate the accuracy of electronic structure methods for determining the minimum barrier height to dissociative chemisorption for H2 + Al(110) on the basis of the standard procedure for comparing results of theory with molecular beam experiments.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.7
DOI: 10.1021/ACS.JPCC.3C00426
|
|
|
“Injectable Plasma‐Treated Alginate Hydrogel for Oxidative Stress Delivery to Induce Immunogenic Cell Death in Osteosarcoma”. Živanić, M, Espona‐Noguera A, Verswyvel H, Smits E, Bogaerts A, Lin A, Canal C, Advanced functional materials (2023). http://doi.org/10.1002/adfm.202312005
Abstract: Cold atmospheric plasma (CAP) is a source of cell‐damaging oxidant molecules that may be used as low‐cost cancer treatment with minimal side effects. Liquids treated with cold plasma and enriched with oxidants are a modality for non‐invasive treatment of internal tumors with cold plasma via injection. However, liquids are easily diluted with body fluids which impedes high and localized delivery of oxidants to the target. As an alternative, plasma‐treated hydrogels (PTH) emerge as vehicles for the precise delivery of oxidants. This study reports an optimal protocol for the preparation of injectable alginate PTH that ensures the preservation of plasma‐generated oxidants. The generation, storage, and release of oxidants from the PTH are assessed. The efficacy of the alginate PTH in cancer treatment is demonstrated in the context of cancer cell cytotoxicity and immunogenicity–release of danger signals and phagocytosis by immature dendritic cells, up to now unexplored for PTH. These are shown in osteosarcoma, a hard‐to‐treat cancer. The study aims to consolidate PTH as a novel cold plasma treatment modality for non‐invasive or postoperative tumor treatment. The results offer a rationale for further exploration of alginate‐based PTHs as a versatile platform in biomedical engineering.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT); Center for Oncological Research (CORE)
Impact Factor: 19
DOI: 10.1002/adfm.202312005
|
|
|
“Plasmonic Near-Field Localization of Silver Core–Shell Nanoparticle Assemblies via Wet Chemistry Nanogap Engineering”. Asapu R, Ciocarlan R-G, Claes N, Blommaerts N, Minjauw M, Ahmad T, Dendooven J, Cool P, Bals S, Denys S, Detavernier C, Lenaerts S, Verbruggen SW, ACS applied materials and interfaces 9, 41577 (2017). http://doi.org/10.1021/acsami.7b13965
Abstract: Silver nanoparticles are widely used in the field of plasmonics because of their unique optical properties. The wavelength-dependent surface plasmon resonance gives rise to a strongly enhanced electromagnetic field, especially at so-called hot spots located in the nanogap in-between metal nanoparticle assemblies. Therefore, the interparticle distance is a decisive factor in plasmonic applications, such as surface-enhanced Raman spectroscopy (SERS). In this study, the aim is to engineer this interparticle distance for silver nanospheres using a convenient wet-chemical approach and to predict and quantify the corresponding enhancement factor using both theoretical and experimental tools. This was done by building a tunable ultrathin polymer shell around the nanoparticles using the layer-by-layer method, in which the polymer shell acts as the separating interparticle spacer layer. Comparison of different theoretical approaches and corroborating the results with SERS analytical experiments using silver and silver−polymer core−shell nanoparticle clusters as SERS substrates was also done. Herewith, an approach is provided to estimate the extent of plasmonic near-field enhancement both theoretically as well as experimentally.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 7.504
Times cited: 29
DOI: 10.1021/acsami.7b13965
|
|
|
“Coupled plasmon modes in 2D gold nanoparticle clusters and their effect on local temperature control”. Borah R, Verbruggen SW, The journal of physical chemistry: C : nanomaterials and interfaces 123, 30594 (2019). http://doi.org/10.1021/ACS.JPCC.9B09048
Abstract: Assemblies of closely separated gold nanoparticles exhibit a strong collective plasmonic response due to coupling of the plasmon modes of the individual nanostructures. In the context of self-assembly of nanoparticles, close-packed two-dimensional (2D) clusters of spherical nanoparticles present an important composite system that promises numerous applications. The present study probes the collective plasmonic characteristics and resulting photothermal behavior of close-packed 2D Au nanoparticle clusters to delineate the effects of the cluster size, interparticle distance, and particle size. Smaller nanoparticles (20 and 40 nm in diameter) that exhibit low individual scattering and high absorption were considered for their relevance to photothermal applications. In contrast to typical literature studies, the present study compares the optical response of clusters of different sizes ranging from a single nanoparticle up to large assemblies of 61 nanoparticles. Increasing the cluster size induces significant changes to the spectral position and optophysical characteristics. Based on the model outcome, an optimal cluster size for maximum absorption per nanoparticle is also determined for enhanced photothermal effects. The effect of the particle size and interparticle distance is investigated to elucidate the nature of interaction in terms of near-field and far-field coupling. The photothermal effect resulting from absorption is compared for different cluster sizes and interparticle distances considering a homogeneous water medium. A strong dependence of the steady-state temperature of the nanoparticles on the cluster size, particle position in the cluster, incident light polarization, and interparticle distance provides new physical insight into the local temperature control of plasmonic nanostructures.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 4.536
DOI: 10.1021/ACS.JPCC.9B09048
|
|
|
“Mesoporous TiO2 from poly(N,N-dimethylacrylamide)-b-polystyrene block copolymers for long-term acetaldehyde photodegradation”. Billet J, Vandewalle S, Meire M, Blommaerts N, Lommens P, Verbruggen SW, De Buysser K, Du Prez F, Van Driesche I, Journal of materials science 55, 1933 (2019). http://doi.org/10.1007/S10853-019-04024-3
Abstract: Although already some mesoporous (2–50 nm) sol–gel TiO2 synthesis strategies exist, no pore size control beyond the 12 nm range is possible without using specialized organic structure-directing agents synthetized via controlled anionic/radical polymerizations. Here, we present the use of reversible addition–fragmentation chain transfer (RAFT) polymerization as a straightforward and industrial applicable alternative to the existing controlled polymerization methods for structure-directing agent synthesis. Poly(N,N-dimethylacrylamide)-block-polystyrene (PDMA-b-PS) block copolymer, synthesized via RAFT, was chosen as structure-directing agent for the formation of the mesoporous TiO2. Crack-free thin layers TiO2 with tunable pores from 8 to 45 nm could be acquired. For the first time, in a detailed and systematic approach, the influence of the block size and dispersity of the block copolymer is experimentally screened for their influence on the final meso-TiO2 layers. As expected, the mesoporous TiO2 pore sizes showed a clear correlation to the polystyrene block size and the dispersity of the PDMA-b-PS block copolymer. Surprisingly, the dispersity of the polymer was shown not to be affecting the standard deviation of the pores. As a consequence, RAFT could be seen as a viable alternative to the aforementioned controlled polymerization reactions for the synthesis of structure-directing agents enabling the formation of mesoporous pore size-controlled TiO2. To examine the photocatalytic activity of the mesoporous TiO2 thin layers, the degradation of acetaldehyde, a known indoor pollutant, was studied. Even after 3 years of aging, the TiO2 thin layer retained most of its activity.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 2.599
Times cited: 2
DOI: 10.1007/S10853-019-04024-3
|
|
|
“Microwave-assisted synthesis of mesoporous titania with increased crystallinity, specific surface area, and photocatalytic activity”. Meire M, Verbruggen SW, Lenaerts S, Lommens P, Van Der Voort P, Van Driessche I, Journal of materials science 51, 9822 (2016). http://doi.org/10.1007/S10853-016-0215-Y
Abstract: Mesoporous titanium dioxide is a material finding its use in a wide range of applications. For many of these, it is important to achieve a high degree of crystallinity in the material. It is generally accepted that the use of the soft templating approach to synthesize mesoporous titania, results in a compromise between crystallinity and specific surface area due to thermal instability of the used templates. In this paper, we explore how the use of microwave irradiation can influence the crystallinity, specific surface area, and the electronic properties of mesoporous titania. Therefore, we combined microwave radiation with an evaporation-induced self-assembly (EISA) synthesis. We show that additional microwave treatment at carefully chosen synthesis steps can enhance the crystallinity with 20 % without causing significant loss of surface area (>360 m2/g). Surface photovoltage measurements were used to investigate the electronic properties. The photocatalytic activity of the samples was evaluated in aqueous media by following the degradation of an industrial dye, methylene blue, and the herbicide isoproturon under UV irradiation and in gaseous media looking at the degradation of acetaldehyde, a common indoor pollutant under UVA irradiation. In all cases, the microwave treatment results in more active materials.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 2.599
Times cited: 8
DOI: 10.1007/S10853-016-0215-Y
|
|