|
“S-SIMS and MetA-SIMS study of organic additives in thin polymer coatings”. Adriaensen L, Vangaever F, Lenaerts J, Gijbels R, Applied surface science 252, 6628 (2006). http://doi.org/10.1016/j.apsusc.2006.02.275
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.387
Times cited: 3
DOI: 10.1016/j.apsusc.2006.02.275
|
|
|
“Stability of Si epoxide defects in Si nanowires : a mixed reactive force field/DFT study”. Schoeters B, Neyts EC, Khalilov U, Pourtois G, Partoens B, Physical chemistry, chemical physics 15, 15091 (2013). http://doi.org/10.1039/c3cp51621k
Abstract: Modeling the oxidation process of silicon nanowires through reactive force field based molecular dynamics simulations suggests that the formation of Si epoxide defects occurs both at the Si/SiOx interface and at the nanowire surface, whereas for flat surfaces, this defect is experimentally observed to occur only at the interface as a result of stress. In this paper, we argue that the increasing curvature stabilizes the defect at the nanowire surface, as suggested by our density functional theory calculations. The latter can have important consequences for the opto-electronic properties of thin silicon nanowires, since the epoxide induces an electronic state within the band gap. Removing the epoxide defect by hydrogenation is expected to be possible but becomes increasingly difficult with a reduction of the diameter of the nanowires.
Keywords: A1 Journal article; Condensed Matter Theory (CMT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.123
Times cited: 3
DOI: 10.1039/c3cp51621k
|
|
|
“A temperature study of mixed AgBr-AgBrI tabular crystals”. Goessens C, Schryvers D, van Landuyt J, Geuens I, Gijbels R, Jacob W, de Keyzer R Hawaii, page 70 (1995).
Keywords: H1 Book chapter; Electron microscopy for materials research (EMAT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Times cited: 3
|
|
|
“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
|
|
|
“Ab-initio study of the segregation and electronic properties of neutral and charged B and P dopants in Si and Si/SiO2 nanowires”. Schoeters B, Leenaerts O, Pourtois G, Partoens B, Journal of applied physics 118, 104306 (2015). http://doi.org/10.1063/1.4930048
Abstract: We perform first-principles calculations to investigate the preferred positions of B and P dopants, both neutral and in their preferred charge state, in Si and Si/SiO2 core-shell nanowires (NWs). In order to understand the observed trends in the formation energy, we isolate the different effects that determine these formation energies. By making the distinction between the unrelaxed and the relaxed formation energy, we separate the impact of the relaxation from that of the chemical environment. The unrelaxed formation energies are determined by three effects: (i) the effect of strain caused by size mismatch between the dopant and the host atoms, (ii) the local position of the band edges, and (iii) a screening effect. In the case of the SiNW (Si/SiO2 NW), these effects result in an increase of the formation energy away from the center (interface). The effect of relaxation depends on the relative size mismatch between the dopant and host atoms. A large size mismatch causes substantial relaxation that reduces the formation energy considerably, with the relaxation being more pronounced towards the edge of the wires. These effects explain the surface segregation of the B dopants in a SiNW, since the atomic relaxation induces a continuous drop of the formation energy towards the edge. However, for the P dopants, the formation energy starts to rise when moving from the center but drops to a minimum just next to the surface, indicating a different type of behavior. It also explains that the preferential location for B dopants in Si/SiO2 core-shell NWs is inside the oxide shell just next to the interface, whereas the P dopants prefer the positions next to the interface inside the Si core, which is in agreement with recent experiments. These preferred locations have an important impact on the electronic properties of these core-shell NWs. Our simulations indicate the possibility of hole gas formation when B segregates into the oxide shell.
Keywords: A1 Journal article; Condensed Matter Theory (CMT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.068
Times cited: 3
DOI: 10.1063/1.4930048
|
|
|
“Effective ionisation coefficients and critical breakdown electric field of CO2at elevated temperature: effect of excited states and ion kinetics”. Wang W, Bogaerts A, Plasma sources science and technology 25, 055025 (2016). http://doi.org/10.1088/0963-0252/25/5/055025
Abstract: Electrical breakdown by the application of an electric field occurs more easily in hot gases than in cold gases because of the extra electron-species interactions that occur as a result of dissociation, ionization and excitation at higher temperature. This paper discusses some overlooked physics and clarifies inaccuracies in the evaluation of the effective ionization coefficients and the critical reduced breakdown electric field of CO2 at elevated temperature, considering the influence of excited states and ion kinetics. The critical reduced breakdown electric field is obtained by balancing electron generation and loss mechanisms using the electron energy distribution function (EEDF) derived from the Boltzmann transport equation under the two-term approximation. The equilibrium compositions of the hot gas mixtures are determined based on Gibbs free energy minimization considering the ground states as well as vibrationally and electronically excited states as independent species, which follow a Boltzmann distribution with a fixed excitation temperature. The interaction cross sections between electrons and the excited species, not reported previously, are properly taken into account. Furthermore, the ion kinetics, including electron–ion recombination, associative electron detachment, charge transfer and ion conversion into stable negative ion clusters, are also considered. Our results indicate that the excited species lead to a greater population of high-energy electrons at higher gas temperature and this affects the Townsend rate coefficients (i.e. of electron impact ionization and attachment), but the critical reduced breakdown electric field strength of CO2 is only affected when also properly accounting for the ion kinetics. Indeed, the latter greatly influences the effective ionization coefficients and hence the critical reduced breakdown electric field at temperatures above 1500 K. The rapid increase of the dissociative electron attachment cross-section of molecular oxygen with rising vibrational quantum number leads to a larger electron loss rate and this enhances the critical reduced breakdown electric field strength in the temperature range where the concentration of molecular oxygen is relatively high. The results obtained in this work show reasonable agreement with experimental results from literature, and are important for the evaluation of the dielectric strength of CO2 in a highly reactive environment at elevated temperature.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.302
Times cited: 3
DOI: 10.1088/0963-0252/25/5/055025
|
|
|
“CO2 conversion in a gliding arc plasma: 1D cylindrical discharge model”. Wang W, Berthelot A, Kolev S, Tu X, Bogaerts A, Plasma sources science and technology 25, 065012 (2016). http://doi.org/10.1088/0963-0252/25/6/065012
Abstract: CO 2 conversion by a gliding arc plasma is gaining increasing interest, but the underlying mechanisms for an energy-efficient process are still far from understood. Indeed, the chemical complexity of the non-equilibrium plasma poses a challenge for plasma modeling due to the huge computational load. In this paper, a one-dimensional (1D) gliding arc model is developed in a cylindrical frame, with a detailed non-equilibrium CO 2 plasma chemistry set, including the CO 2 vibrational kinetics up to the dissociation limit. The model solves a set of time- dependent continuity equations based on the chemical reactions, as well as the electron energy balance equation, and it assumes quasi-neutrality in the plasma. The loss of plasma species and heat due to convection by the transverse gas flow is accounted for by using a characteristic frequency of convective cooling, which depends on the gliding arc radius, the relative velocity of the gas flow with respect to the arc and on the arc elongation rate. The calculated values for plasma density and plasma temperature within this work are comparable with experimental data on gliding arc plasma reactors in the literature. Our calculation results indicate that excitation to the vibrational levels promotes efficient dissociation in the gliding arc, and this is consistent with experimental investigations of the gliding arc based CO 2 conversion in the literature. Additionally, the dissociation of CO 2 through collisions with O atoms has the largest contribution to CO 2 splitting under the conditions studied. In addition to the above results, we also demonstrate that lumping the CO 2 vibrational states can bring a significant reduction of the computational load. The latter opens up the way for 2D or 3D models with an accurate description of the CO 2 vibrational kinetics.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.302
Times cited: 3
DOI: 10.1088/0963-0252/25/6/065012
|
|
|
“Special Issue on Numerical Modelling of Low-Temperature Plasmas for Various Applications –, Part I: Review and Tutorial Papers on Numerical Modelling Approaches”. Alves LL, Bogaerts A, Plasma processes and polymers 14, 1690011 (2017). http://doi.org/10.1002/ppap.201690011
Keywords: Editorial; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.846
Times cited: 3
DOI: 10.1002/ppap.201690011
|
|
|
“Atomistic simulations of graphite etching at realistic time scales”. Aussems DUB, Bal K M, Morgan TW, van de Sanden MCM, Neyts EC, Chemical science 8, 7160 (2017). http://doi.org/10.1039/C7SC02763J
Abstract: Hydrogen–graphite interactions are relevant to a wide variety of applications, ranging from astrophysics to fusion devices and nano-electronics. In order to shed light on these interactions, atomistic simulation using Molecular Dynamics (MD) has been shown to be an invaluable tool. It suffers, however, from severe timescale
limitations. In this work we apply the recently developed Collective Variable-Driven Hyperdynamics (CVHD) method to hydrogen etching of graphite for varying inter-impact times up to a realistic value of 1 ms, which corresponds to a flux of 1020 m2 s1. The results show that the erosion yield, hydrogen surface coverage and species distribution are significantly affected by the time between impacts. This can be explained by the higher probability of C–C bond breaking due to the prolonged exposure to thermal stress and the subsequent transition from ion- to thermal-induced etching. This latter regime of thermal-induced etching – chemical erosion – is here accessed for the first time using atomistic simulations. In conclusion, this study demonstrates that accounting for long time-scales significantly affects ion bombardment simulations and should not be neglected in a wide range of conditions, in contrast to what is typically assumed.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 8.668
Times cited: 3
DOI: 10.1039/C7SC02763J
|
|
|
“Thermodynamic properties and transport coefficients of a two-temperature polytetrafluoroethylene vapor plasma for ablation-controlled discharge applications”. Wang H, Wang W, Yan JD, Qi H, Geng J, Wu Y, Journal of physics: D: applied physics 50, 395204 (2017). http://doi.org/10.1088/1361-6463/AA7D68
Abstract: Ablation-controlled plasmas have been used in a range of technical applications where local thermodynamic equilibrium (LTE) is often violated near the wall due to the strong cooling effect caused by the ablation of wall materials. The thermodynamic and transport properties of ablated polytetrafluoroethylene (PTFE) vapor, which determine the flowing plasma behavior in such applications, are calculated based on a two-temperature model at atmospheric pressure. To our knowledge, no data for PTFE have been reported in the literature. The species composition and thermodynamic properties are numerically determined using the two-temperature Saha equation and the Guldberg-Waage equation according to van de Sanden et al's derivation. The transport coefficients, including viscosity, thermal conductivity and electrical conductivity, are calculated with the most recent collision interaction potentials using Devoto's electron and heavy-particle decoupling approach but expanded to the third-order approximation (second-order for viscosity) in the frame of the Chapman-Enskog method. Results are computed for different degrees of thermal non-equilibrium, i.e. the ratio of electron to heavy-particle temperatures, from 1 to 10, with electron temperature ranging from 300 to 40 000 K. Plasma transport properties in the LTE state obtained from the present work are compared with existing published results and the causes for the discrepancy analyzed. The two-temperature plasma properties calculated in the present work enable the modeling of wall ablation-controlled plasma processes.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.588
Times cited: 3
DOI: 10.1088/1361-6463/AA7D68
|
|
|
“Study of an AC dielectric barrier single micro-discharge filament over a water film”. Vanraes P, Nikiforov A, Bogaerts A, Leys C, Scientific reports 8, 10919 (2018). http://doi.org/10.1038/s41598-018-29189-w
Abstract: In the last decades, AC powered atmospheric dielectric barrier discharges (DBDs) in air with a liquid electrode have been proposed as a promising plasma technology with versatile applicability in medicine agriculture and water treatment. The fundamental features of the micro-discharge filaments that make up this type of plasma have, however, not been studied yet in sufficient detail. In order to address this need, we investigated a single DBD micro-discharge filament over a water film in a sphere-to-sphere electrode configuration, by means of ICCD imaging and optical emission spectroscopy. When the water film temporarily acts as the cathode, the plasma duration is remarkably long and shows a clear similarity with a resistive barrier discharge, which we attribute to the resistive nature of the water film and the formation of a cathode fall. As another striking difference to DBD with solid electrodes, a constant glow-like plasma is observed at the water surface during the entire duration of the applied voltage cycle, indicating continuous plasma treatment of the liquid. We propose several elementary mechanisms that might underlie the observed unique behavior, based on the specific features of a water electrode.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.259
Times cited: 3
DOI: 10.1038/s41598-018-29189-w
|
|
|
“Plasma streamer propagation in structured catalysts”. Zhang Q-Z, Bogaerts A, Plasma Sources Science &, Technology 27, 105013 (2018). http://doi.org/10.1088/1361-6595/aae430
Abstract: Plasma catalysis is gaining increasing interest for various environmental applications. Catalytic
material can be inserted in different shapes in the plasma, e.g., as pellets, (coated) beads, but also
as honeycomb monolith and 3DFD structures, also called ‘structured catalysts’, which have high
mass and heat transfer properties. In this work, we examine the streamer discharge propagation
and the interaction between plasma and catalysts, inside the channels of such structured catalysts,
by means of a two-dimensional particle-in-cell/Monte Carlo collision model. Our results reveal
that plasma streamers behave differently in various structured catalysts. In case of a honeycomb
structure, the streamers are limited to only one channel, with low or high plasma density when
the channels are parallel or perpendicular to the electrodes, respectively. In contrast, in case of a
3DFD structure, the streamers can distribute to different channels, causing discharge
enhancement due to surface charging on the dielectric walls of the structured catalyst, and
especially giving rise to a broader plasma distribution. The latter should be beneficial for plasma
catalysis applications, as it allows a larger catalyst surface area to be exposed to the plasma.
Keywords: A1 Journal Article; plasma catalysis, streamer propagation, 3D structures, PIC/MCC; Plasma, laser ablation and surface modeling Antwerp (PLASMANT) ;
Impact Factor: 3.302
Times cited: 3
DOI: 10.1088/1361-6595/aae430
|
|
|
“How process parameters and packing materials tune chemical equilibrium and kinetics in plasma-based CO2 conversion”. Uytdenhouwen Y, Bal Km, Michielsen I, Neyts Ec, Meynen V, Cool P, Bogaerts A, Chemical engineering journal 372, 1253 (2019). http://doi.org/10.1016/j.cej.2019.05.008
Abstract: Plasma (catalysis) reactors are increasingly being used for gas-based chemical conversions, providing an alternative method of energy delivery to the molecules. In this work we explore whether classical concepts such as
equilibrium constants, (overall) rate coefficients, and catalysis exist under plasma conditions. We specifically
investigate the existence of a so-called partial chemical equilibrium (PCE), and how process parameters and
packing properties influence this equilibrium, as well as the overall apparent rate coefficient, for CO2 splitting in
a DBD plasma reactor. The results show that a PCE can be reached, and that the position of the equilibrium, in
combination with the rate coefficient, greatly depends on the reactor parameters and operating conditions (i.e.,
power, pressure, and gap size). A higher power, higher pressure, or smaller gap size enhance both the equilibrium constant and the rate coefficient, although they cannot be independently tuned. Inserting a packing
material (non-porous SiO2 and ZrO2 spheres) in the reactor reveals interesting gap/material effects, where the
type of material dictates the position of the equilibrium and the rate (inhibition) independently. As a result, no
apparent synergistic effect or plasma-catalytic behaviour was observed for the non-porous packing materials
studied in this reaction. Within the investigated parameters, equilibrium conversions were obtained between 23
and 71%, while the rate coefficient varied between 0.027 s−1 and 0.17 s−1. This method of analysis can provide
a more fundamental insight in the overall reaction kinetics of (catalytic) plasma-based gas conversion, in order
to be able to distinguish plasma effects from true catalytic enhancement.
Keywords: A1 Journal article; Laboratory of adsorption and catalysis (LADCA); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 6.216
Times cited: 3
DOI: 10.1016/j.cej.2019.05.008
|
|
|
“Combining CO2 conversion and N2 fixation in a gliding arc plasmatron”. Ramakers M, Heijkers S, Tytgat T, Lenaerts S, Bogaerts A, Journal of CO2 utilization 33, 121 (2019). http://doi.org/10.1016/j.jcou.2019.05.015
Abstract: Industry needs a flexible and efficient technology to convert CO2 into useful products, which fits in the Carbon Capture and Utilization (CCU) philosophy. Plasma technology is intensively being investigated for this purpose. A promising candidate is the gliding arc plasmatron (GAP). Waste streams of CO2 are often not pure and contain N2 as important impurity. Therefore, in this paper we provide a detailed experimental and computational study of the combined CO2 and N2 conversion in a GAP. Is it possible to take advantage of the presence of N2 in the mixture and to combine CO2 conversion with N2 fixation? Our experiments and simulations reveal that N2 actively contributes to the process of CO2 conversion, through its vibrational levels. In addition, NO and NO2 are formed, with concentrations around 7000 ppm, which is slightly too low for valorization, but by improving the reactor design it must be possible to further increase their concentrations. Other NO-based molecules, in particular the strong greenhouse gas N2O, are not formed in the GAP, which is an important result. We also compare our results with those obtained in other plasma reactors to clarify the differences in underlying plasma processes, and to demonstrate the superiority of the GAP.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT); Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 4.292
Times cited: 3
DOI: 10.1016/j.jcou.2019.05.015
|
|
|
“Transport of cystine across xC-antiporter”. Ghasemitarei M, Yusupov M, Razzokov J, Shokri B, Bogaerts A, Archives of biochemistry and biophysics 664, 117 (2019). http://doi.org/10.1016/j.abb.2019.01.039
Abstract: Extracellular cystine (CYC) uptake by xC antiporter is important for the cell viability. Especially in cancer cells, the upregulation of xC activity is observed, which protects these cells from intracellular oxidative stress. Hence, inhibition of the CYC uptake may eventually lead to cancer cell death. Up to now, the molecular level mechanism of the CYC uptake by xC antiporter has not been studied in detail. In this study, we applied several different simulation techniques to investigate the transport of CYC through xCT, the light subunit of the xC antiporter, which is responsible for the CYC and glutamate translocation. Specifically, we studied the permeation of CYC across three model systems, i.e., outward facing (OF), occluded (OCC) and inward facing (IF) configurations of xCT. We also investigated the effect of mutation of Cys327 to Ala within xCT, which was also studied experimentally in literature. This allowed us to qualitatively compare our computation results with experimental observations, and thus, to validate our simulations. In summary, our simulations provide a molecular level mechanism of the transport of CYC across the xC antiporter, more specifically, which amino acid residues in the xC antiporter play a key role in the uptake, transport and release of CYC.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.165
Times cited: 3
DOI: 10.1016/j.abb.2019.01.039
|
|
|
“Molecular dynamics simulations of initial Pd and PdO nanocluster growth in a magnetron gas aggregation source”. Brault P, Chamorro-Coral W, Chuon S, Caillard A, Bauchire J-M, Baranton S, Coutanceau C, Neyts E, Frontiers of Chemical Science and Engineering 13, 324 (2019). http://doi.org/10.1007/S11705-019-1792-5
Abstract: Molecular dynamics simulations are carried out for describing growth of Pd and PdO nanoclusters using the ReaxFF force field. The resulting nanocluster structures are successfully compared to those of nanoclusters experimentally grown in a gas aggregation source. The PdO structure is quasi-crystalline as revealed by high resolution transmission microscope analysis for experimental PdO nanoclusters. The role of the nanocluster temperature in the molecular dynamics simulated growth is highlighted.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 1.712
Times cited: 3
DOI: 10.1007/S11705-019-1792-5
|
|
|
“Ovonic threshold-switching GexSey chalcogenide materials : stoichiometry, trap nature, and material relaxation from first principles”. Clima S, Garbin D, Opsomer K, Avasarala NS, Devulder W, Shlyakhov I, Keukelier J, Donadio GL, Witters T, Kundu S, Govoreanu B, Goux L, Detavernier C, Afanas'ev V, Kar GS, Pourtois G, Physica Status Solidi-Rapid Research Letters , 1900672 (2020). http://doi.org/10.1002/PSSR.201900672
Abstract: Density functional theory simulations are used to identify the structural factors that define the material properties of ovonic threshold switches (OTS). They show that the nature of mobility-gap trap states in amorphous Ge-rich Ge50Se50 is related to Ge-Ge bonds, whereas in Se-rich Ge30Se70 the Ge valence-alternating-pairs and Se lone-pairs dominate. To obtain a faithful description of the electronic structure and delocalization of states, it is required to combine hybrid exchange-correlation functionals with large unit-cell models. The extent of localization of electronic states depends on the applied external electric field. Hence, OTS materials undergo structural changes during electrical cycling of the device, with a decrease in the population of less exothermic Ge-Ge bonds in favor of more exothermic Ge-Se. This reduces the amount of charge traps, which translates into coordination changes, an increase in mobility-gap, and subsequently changes in the selector-device electrical parameters. The threshold voltage drift process can be explained by natural evolution of the nonpreferred Ge-Ge bonds (or “chains”/clusters thereof) in Ge-rich GexSe1-x. The effect of extrinsic doping is shown for Si and N, which introduce strong covalent bonds into the system, increase both mobility-gap and crystallization temperature, and decrease the leakage current.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.8
Times cited: 3
DOI: 10.1002/PSSR.201900672
|
|
|
“Plasma-catalytic ammonia synthesis : packed catalysts act as plasma modifiers”. Ndayirinde C, Gorbanev Y, Ciocarlan R-G, De Meyer R, Smets A, Vlasov E, Bals S, Cool P, Bogaerts A, Catalysis today 419, 114156 (2023). http://doi.org/10.1016/J.CATTOD.2023.114156
Abstract: We studied the plasma-catalytic production of NH3 from H2 and N2 in a dielectric barrier discharge plasma reactor using five different Co-based catalysts supported on Al2O3, namely Co/Al2O3, CoCe/Al2O3, CoLa/Al2O3, CoCeLa/Al2O3 and CoCeMg/Al2O3. The catalysts were characterized via several techniques, including SEM-EDX, and their performance was compared. The best performing catalyst was found to be CoLa/Al2O3, but the dif-ferences in NH3 concentration, energy consumption and production rate between the different catalysts were limited under the same conditions (i.e. feed gas, flow rate and ratio, and applied power). At the same time, the plasma properties, such as the plasma power and current profile, varied significantly depending on the catalyst. Taken together, these findings suggest that in the production of NH3 by plasma catalysis, our catalysts act as plasma modifiers, i.e., they change the discharge properties and hence the gas phase plasma chemistry. Importantly, this effect dominates over the direct catalytic effect (as e.g. in thermal catalysis) defined by the chemistry on the catalyst surface.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 5.3
Times cited: 3
DOI: 10.1016/J.CATTOD.2023.114156
|
|
|
“Capabilities and limitations of Fourier transform laser microprobe mass spectrometry for molecular analysis of solids”. Ignatova VA, van Vaeck L, Gijbels R, Adams F, Vacuum 69, 307 (2002). http://doi.org/10.1016/S0042-207X(02)00350-0
Abstract: Fourier transform laser microprobe mass spectrometry (FT LMMS) has been developed for the molecular analysis of both organic and inorganic components at the surface of microobjects with the ultimate specificity of high-mass resolution. These capabilities are needed in numerous applications of practical material analysis, such as tracing back anomalies in microobjects. The purpose of this paper is to address representative example from industrial trouble shooting, in which organic and inorganic analytes in a single microparticle have been identified unambiguously. This motivates the research to extend the methodology towards quantification. This paper deals with the fundamental aspect of information depth, specifically for inorganic molecular adduct ions. Finally, data will show the quantitative capabilities of FT LMMS. A suitable methodology for the preparation of reference specimens has allowed the empirical calibration of the response as a function of the local concentration to be achieved.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 1.53
Times cited: 4
DOI: 10.1016/S0042-207X(02)00350-0
|
|
|
“Characterization of LPE grown InGaAsP/InP heterostructures: IR-LED at 1.66 μm used for the remote monitoring of methane gas”. Volkov VV, van Landuyt J, Marushkin KM, Gijbels R, Férauge C, Vasilyev MG, Shelyakin AA, Sokolovsky AA, Journal of crystal growth 173, 285 (1997)
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 1.751
Times cited: 4
|
|
|
“Combined characterization of composite tabular silver halide microcrystals by cryo-EFTEM/EELS and cryo-STEM/EDX techniques”. Oleshko VP, Gijbels RH, van Daele AJ, Jacob WA, Xu Y-E, Wang S-E, Park I-Y, Kang T-S, Microscopy research and technique 42, 108 (1998). http://doi.org/10.1002/(SICI)1097-0029(19980715)42:2<108::AID-JEMT5>3.0.CO;2-P
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 1.147
Times cited: 4
DOI: 10.1002/(SICI)1097-0029(19980715)42:2<108::AID-JEMT5>3.0.CO;2-P
|
|
|
“Comparative study of organic dyes with time-of-flight static secondary ion mass spectrometry and related techniques”. Adriaensen L, Vangaever F, Lenaerts J, Gijbels R, Journal of mass spectrometry 40, 615 (2005). http://doi.org/10.1002/jms.832
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.422
Times cited: 4
DOI: 10.1002/jms.832
|
|
|
“Depth profiling of ZrO2/SiO2/Si stacks : a TOF-SIMS and computer simulation study”. Ignatova VA, Conard T, Möller W, Vandervorst W, Gijbels R, Applied surface science 231/232, 603 (2004). http://doi.org/10.1016/j.apsusc.2004.03.121
Abstract: This study is dedicated to a better understanding of the processes occurring under ion bombardment of ultra-thin ZrO2/SiO2/Si gate dielectric stacks. Complex-shaped depth profiles were obtained by using TOF-SIMS with dual beam (500 eV for sputtering and 10 keV for analysis) Ar+ ions. The SIMS intensities of all the elements depend critically on the amount of oxygen at any moment of the sputtering process. Increased intensity is observed at the surface and at the ZrO2/SiO2 interface. A long tail of the Zr signal is present in the Si substrate, even after the second (SiO2/Si) interface, and a double bump structure in the Zr-90 and ZrO dimer is observed, which is more pronounced with increasing thickness of the interfacial SiO2 layer. Computer simulations using the dynamic Monte Carlo code (TRIDYN) are performed in order to distinguish the ion bombardment-induced effects from changes in the ionization degree. The original code is extended with simple models for the ionization mechanism and for the molecular yield during sputtering. Oxygen preferential sputtering at the surface and ballistic transport of Zr towards and through the interface are clearly demonstrated, but there is also evidence that due to recoil implantation oxygen gets piled-up near the ZrO2/SiO2 interface. (C) 2004 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.387
Times cited: 4
DOI: 10.1016/j.apsusc.2004.03.121
|
|
|
“Dissolution study of potassium feldspars using hydrothermally treated sanidine as an example”. Adriaens A, Goossens D, Pijpers A, Van Tendeloo G, Gijbels R, Surface and interface analysis 27, 8 (1999). http://doi.org/10.1002/(SICI)1096-9918(199901)27:1<8::AID-SIA456>3.0.CO;2-Z
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT); Electron microscopy for materials research (EMAT)
Impact Factor: 1.132
Times cited: 4
DOI: 10.1002/(SICI)1096-9918(199901)27:1<8::AID-SIA456>3.0.CO;2-Z
|
|
|
“Elucidating the asymmetric behavior of the discharge in a dual magnetron sputter deposition system”. Yusupov M, Bultinck E, Depla D, Bogaerts A, Applied physics letters 98, 131502 (2011). http://doi.org/10.1063/1.3574365
Abstract: A magnetron discharge is characterized by drifts of the charged particles guiding center, caused by the magnetic field, in contrast to unmagnetized discharges. Because of these drifts, a pronounced asymmetry of the discharge can be observed in a dual magnetron setup. In this work, it is found that the shape of the discharge in a dual magnetron configuration depends on the magnetic field configuration. In a closed configuration, strong drifts were observed in one preferential direction, whereas in a mirror configuration the deflection of the discharge was not so pronounced. Our calculations confirm experimental observations.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.411
Times cited: 4
DOI: 10.1063/1.3574365
|
|
|
“Ground state configurations of two-dimensional plasma crystals under long-range attractive particle interaction force”. Chen Z, Kong M, Milošević, MV, Wu Y, Physica scripta 67, 439 (2003). http://doi.org/10.1238/Physica.Regular.067a00439
Keywords: A1 Journal article; Condensed Matter Theory (CMT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 1.28
Times cited: 4
DOI: 10.1238/Physica.Regular.067a00439
|
|
|
“The influence of Cr and Y on the micro structural evolution of Mg―Cr―O and Mg―Y―O thin films”. Jehanathan N, Georgieva V, Saraiva M, Depla D, Bogaerts A, Van Tendeloo G, Thin solid films : an international journal on the science and technology of thin and thick films 519, 5388 (2011). http://doi.org/10.1016/j.tsf.2011.02.050
Abstract: The compositional influence of Cr and Y on the microstructure of Mg―Cr―O, and Mg―Y―O films synthesized by reactive magnetron sputtering has been investigated by transmission electron microscopy, X-ray diffraction and molecular dynamics simulations. A decrease in crystallinity is observed in these films as the M (Cr or Y) content is increased. It is found that M forms a solid solution with MgO for metal ratios up to ~ 70% and ~ 50% for Cr and Y respectively. Above ~ 70% Cr metal ratio the Mg―Cr―O films are found to be completely amorphous. The Mg―Y―O films are composed of Mg(Y)O and Y2O3 nano crystallites, up to ~ 50% Y metal ratio. Above this ratio, only Y2O3 nano crystallites are found. The preferential < 111> MgO grain alignment is strongly affected by the increase in M content. For M metal ratios up to ~ 50%, there is a selective promotion of the < 100> MgO grain alignments and a decline in the < 111> grain alignments.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT); Electron microscopy for materials research (EMAT)
Impact Factor: 1.879
Times cited: 4
DOI: 10.1016/j.tsf.2011.02.050
|
|
|
“Interpretation of TOF-SIMS depth profiles from ultrashallow high-k dielectric stacks assisted by hybrid collisional computer simulation”. Ignatova VA, Möller W, Conard T, Vandervorst W, Gijbels R, Applied physics A : materials science &, processing 81, 71 (2005). http://doi.org/10.1007/s00339-005-3239-8
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 1.455
Times cited: 4
DOI: 10.1007/s00339-005-3239-8
|
|
|
“Kinetic modeling of relaxation phenomena after photodetachment in a rf electronegative SiH4 discharge”. Yan M, Bogaerts A, Gijbels R, Physical review : E : statistical physics, plasmas, fluids, and related interdisciplinary topics 63 (2001). http://doi.org/10.1103/PhysRevE.63.026405
Abstract: The global relaxation process after pulsed laser induced photodetachment in a rf electronegative SIH4 discharge is studied by a self-consistent kinetic one-dimensional particle-in-cell-Monte Carlo model. Our results reveal a comprehensive physical picture of the relaxation process, including the main plasma variables, after a perturbation up to the full recovery of the steady state. A strong influence of the photodetachment on the discharge is found, which results from an increase of the electron density, leading to a weaker bulk field, and hence to a drop in the high energy tail of the electron energy distribution function (EEDF), a reduction of the reaction rates of electron impact attachment and ionization, and a subsequent decrease of the positive and negative ion densities. All the plasma quantities related to electrons recover synchronously. The recovery time of the ion densities is about 1-2 orders of magnitude longer than that of the electrons due to different recovery mechanisms. The modeled behavior of all the charged particles agrees very well with experimental results from the literature. In addition, our work clarifies some unclear processes assumed in the literature, such as the relaxation of the EEDF, the evolution of the electric field, and the recovery of negative ions.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.366
Times cited: 4
DOI: 10.1103/PhysRevE.63.026405
|
|
|
“Quantitative secondary ion mass spectrometry depth profiling of surface layers of cubic silver halide microcrystals”. Verlinden G, Gijbels R, Geuens I, Journal of the American Society for Mass Spectrometry 10, 1016 (1999). http://doi.org/10.1016/S1044-0305(99)00064-1
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.786
Times cited: 4
DOI: 10.1016/S1044-0305(99)00064-1
|
|