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“Electrostatic modes in multi-ion and pair-ion collisional plasmas”. Vranjes J, Petrovic D, Pandey BP, Poedts S, Physics of plasmas 15, 072104 (2008). http://doi.org/10.1063/1.2949696
Abstract: The physics of plasmas containing positive and negative ions is discussed with special attention to the recently produced pair-ion plasma containing ions of equal mass and opposite charge. The effects of the density gradient in the direction perpendicular to the ambient magnetic field vector are discussed. The possible presence of electrons is discussed in the context of plasma modes propagating at an angle with respect to the magnetic field vector. It is shown that the electron plasma mode may become a backward mode in the presence of a density gradient, and this behavior may be controlled either by the electron number density or the mode number in the perpendicular direction. In plasmas with hot electrons an instability may develop, driven by the combination of electron collisions and the density gradient, and in the regime of a sound ions' response. In the case of a pure pair-ion plasma, for lower frequencies and for parameters close to those used in the recent experiments, the perturbed ions may feel the effects of the magnetic field. In this case the plasma mode also becomes backward, resembling features of an experimentally observed but yet unexplained backward mode. (C) 2008 American Institute of Physics.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.115
Times cited: 54
DOI: 10.1063/1.2949696
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“Atomic spectroscopy”. Bings NH, Bogaerts A, Broekaert JAC, Analytical chemistry 80, 4317 (2008). http://doi.org/10.1021/ac8006297
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 6.32
Times cited: 53
DOI: 10.1021/ac8006297
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“Molecular dynamics simulations for the growth of diamond-like carbon films from low kinetic energy species”. Neyts E, Bogaerts A, Gijbels R, Benedikt J, van den Sanden MCM, Diamond and related materials 13, 1873 (2004). http://doi.org/10.1016/j.diamond.2004.05.011
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.561
Times cited: 53
DOI: 10.1016/j.diamond.2004.05.011
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“Atomistic modelling of CVD synthesis of carbon nanotubes and graphene”. Elliott JA, Shibuta Y, Amara H, Bichara C, Neyts EC, Nanoscale 5, 6662 (2013). http://doi.org/10.1039/c3nr01925j
Abstract: We discuss the synthesis of carbon nanotubes (CNTs) and graphene by catalytic chemical vapour deposition (CCVD) and plasma-enhanced CVD (PECVD), summarising the state-of-the-art understanding of mechanisms controlling their growth rate, chiral angle, number of layers (walls), diameter, length and quality (defects), before presenting a new model for 2D nucleation of a graphene sheet from amorphous carbon on a nickel surface. Although many groups have modelled this process using a variety of techniques, we ask whether there are any complementary ideas emerging from the different proposed growth mechanisms, and whether different modelling techniques can give the same answers for a given mechanism. Subsequently, by comparing the results of tight-binding, semi-empirical molecular orbital theory and reactive bond order force field calculations, we demonstrate that graphene on crystalline Ni(111) is thermodynamically stable with respect to the corresponding amorphous metal and carbon structures. Finally, we show in principle how a complementary heterogeneous nucleation step may play a key role in the transformation from amorphous carbon to graphene on the metal surface. We conclude that achieving the conditions under which this complementary crystallisation process can occur may be a promising method to gain better control over the growth processes of both graphene from flat metal surfaces and CNTs from catalyst nanoparticles.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 7.367
Times cited: 52
DOI: 10.1039/c3nr01925j
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“Investigating the plasma chemistry for the synthesis of carbon nanotubes/nanofibres in an inductively coupled plasma enhanced CVD system : the effect of different gas mixtures”. Mao M, Bogaerts A, Journal of physics: D: applied physics 43, 205201 (2010). http://doi.org/10.1088/0022-3727/43/20/205201
Abstract: A hybrid model, called the hybrid plasma equipment model (HPEM), was used to study an inductively coupled plasma in gas mixtures of H2 or NH3 with CH4 or C2H2 used for the synthesis of carbon nanotubes or carbon nanofibres (CNTs/CNFs). The plasma properties are discussed for different gas mixtures at low and moderate pressures, and the growth precursors for CNTs/CNFs are analysed. It is found that C2H2, C2H4 and C2H6 are the predominant molecules in CH4 containing plasmas besides the feedstock gas, and serve as carbon sources for CNT/CNF formation. On the other hand, long-chain hydrocarbons are observed in C2H2-containing plasmas. Furthermore, the background gases CH4 and C2H2 show a different decomposition rate with H2 or NH3 addition at moderate pressures.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.588
Times cited: 52
DOI: 10.1088/0022-3727/43/20/205201
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“The ion- and atom-induced secondary electron emission yield: numerical study for the effect of clean and dirty cathode surfaces”. Bogaerts A, Gijbels R, Plasma sources science and technology 11, 27 (2002). http://doi.org/10.1088/0963-0252/11/1/303
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.302
Times cited: 51
DOI: 10.1088/0963-0252/11/1/303
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“Reactive molecular dynamics simulations of oxygen species in a liquid water layer of interest for plasma medicine”. Yusupov M, Neyts EC, Simon P, Berdiyorov G, Snoeckx R, van Duin ACT, Bogaerts A, Journal of physics: D: applied physics 47, 025205 (2014). http://doi.org/10.1088/0022-3727/47/2/025205
Abstract: The application of atmospheric pressure plasmas in medicine is increasingly gaining attention in recent years, although very little is currently known about the plasma-induced processes occurring on the surface of living organisms. It is known that most bio-organisms, including bacteria, are coated by a liquid film surrounding them, and there might be many interactions between plasma species and the liquid layer before the plasma species reach the surface of the bio-organisms. Therefore, it is essential to study the behaviour of the reactive species in a liquid film, in order to determine whether these species can travel through this layer and reach the biomolecules, or whether new species are formed along the way. In this work, we investigate the interaction of reactive oxygen species (i.e. O, OH, HO2 and H2O2) with water, which is assumed as a simple model system for the liquid layer surrounding biomolecules. Our computational investigations show that OH, HO2 and H2O2 can travel deep into the liquid layer and are hence in principle able to reach the bio-organism. Furthermore, O, OH and HO2 radicals react with water molecules through hydrogen-abstraction reactions, whereas no H-abstraction reaction takes place in the case of H2O2. This study is important to gain insight into the fundamental operating mechanisms in plasma medicine, in general, and the interaction mechanisms of plasma species with a liquid film, in particular.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.588
Times cited: 51
DOI: 10.1088/0022-3727/47/2/025205
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“Defect healing and enhanced nucleation of carbon nanotubes by low-energy ion bombardment”. Neyts EC, Ostrikov K, Han ZJ, Kumar S, van Duin ACT, Bogaerts A, Physical review letters 110, 065501 (2013). http://doi.org/10.1103/PhysRevLett.110.065501
Abstract: Structural defects inevitably appear during the nucleation event that determines the structure and properties of single-walled carbon nanotubes. By combining ion bombardment experiments with atomistic simulations we reveal that ion bombardment in a suitable energy range allows these defects to be healed resulting in an enhanced nucleation of the carbon nanotube cap. The enhanced growth of the nanotube cap is explained by a nonthermal ion-induced graphene network restructuring mechanism.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 8.462
Times cited: 50
DOI: 10.1103/PhysRevLett.110.065501
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“Potential energy surface of B4 and the total atomization energies of B2, B3 and B4”. Martin JML, François JP, Gijbels R, Chemical physics letters 189, 529 (1992)
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 1.897
Times cited: 50
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“Role of Ar2+ and Ar+2 ions in a direct current argon glow discharge: a numerical description”. Bogaerts A, Gijbels R, Journal of applied physics 86, 4124 (1999). http://doi.org/10.1063/1.371337
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.068
Times cited: 50
DOI: 10.1063/1.371337
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“Fluid modelling of a packed bed dielectric barrier discharge plasma reactor”. Van Laer K, Bogaerts A, Plasma sources science and technology 25, 015002 (2016). http://doi.org/10.1088/0963-0252/25/1/015002
Abstract: A packed bed dielectric barrier discharge plasma reactor is computationally studied with a fluid model. Two different complementary axisymmetric 2D geometries are used to mimic the intrinsic 3D problem. It is found that a packing enhances the electric field strength and electron temperature at the contact points of the dielectric material due to polarization of the beads by the applied potential. As a result, these contact points prove to be of direct importance to initiate the plasma. At low applied potential, the discharge stays at the contact points, and shows the properties of a Townsend discharge. When a high enough potential is applied, the plasma will be able to travel through the gaps in between the beads from wall to wall, forming a kind of glow discharge. Therefore, the inclusion of a so-called ‘channel of voids’ is indispensable in any type of packed bed modelling.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.302
Times cited: 50
DOI: 10.1088/0963-0252/25/1/015002
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“Determination of precious metals in ores and rocks by thermal neutron activation/\gamma-spectrometry after preconcentration by nickel sulphide fire assay and coprecipitation with tellurium”. Shazali I, Van 't dack L, Gijbels R, Analytica chimica acta 196, 49 (1987). http://doi.org/10.1016/S0003-2670(00)83069-X
Abstract: The six platinum group elements (Ru, Rh, Pd, Os, Ir and Pt) can be determined in geological samples down to the μg kg−1 level, by using nickel sulphide fire assay and neutron activation of the residue ramaining after dissolution of the nickel sulphide button in concentrated hydrochloric acid. Losses for the platinum group elements during this dissolution step are usually insignificant, except when the elements are present at ultra-trace levels. The can be recovered from the filtrate by coprecipitation with tellerium. The latter approach also permits determination of silver, which is significantly lost in the hydrochloric acid treatment (recovery <98% instead of typically ≈ 10%). The coprecipitation with tellurium considerably improves the results for gold (recovery ≈ 95% instead of typically 75%).
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.513
Times cited: 49
DOI: 10.1016/S0003-2670(00)83069-X
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“Engineering the electronic properties of silicene by tuning the composition of MoX2 and GaX (X = S,Se,Te) chalchogenide templates”. Scalise E, Houssa M, Cinquanta E, Grazianetti C, van den Broek B, Pourtois G, Stesmans A, Fanciulli M, Molle A, 2D materials 1, 011010 (2014). http://doi.org/10.1088/2053-1583/1/1/011010
Abstract: By using first-principles simulations, we investigate the interaction of a 2D silicon layer with two classes of chalcogenide-layered compounds, namely MoX2 and GaX (X = S, Se, Te). A rather weak (van der Waals) interaction between the silicene layers and the chalcogenide layers is predicted. We found that the buckling of the silicene layer is correlated to the lattice mismatch between the silicene layer and the MoX2 or GaX template. The electronic properties of silicene on these different templates largely depend on the buckling of the silicene layer: highly buckled silicene on MoS2 is predicted to be metallic, while low buckled silicene on GaS and GaSe is predicted to be semi-metallic, with preserved Dirac cones at the K points. These results indicate new routes for artificially engineering silicene nanosheets, providing tailored electronic properties of this 2D layer on non-metallic substrates. These non-metallic templates also open the way to the possible integration of silicene in future nanoelectronic devices.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 6.937
Times cited: 49
DOI: 10.1088/2053-1583/1/1/011010
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“Fundamental aspects and applications of glow discharge spectrometric techniques”. Bogaerts A, Gijbels R, Spectrochimica acta: part B : atomic spectroscopy 53, 1 (1998). http://doi.org/10.1016/S0584-8547(97)00122-5
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.241
Times cited: 49
DOI: 10.1016/S0584-8547(97)00122-5
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“Hybrid Monte Carlo: fluid model for studying the effects of nitrogen addition to argon glow discharges”. Bogaerts A, Spectrochimica acta: part B : atomic spectroscopy 64, 126 (2009). http://doi.org/10.1016/j.sab.2008.11.004
Abstract: A computer model is developed for describing argon/nitrogen glow discharges. The species taken into account in the model include electrons, Ar atoms in the ground state and in the 4s metastable levels, N2 molecules in the ground state and in six different electronically excited levels, N atoms, Ar+ ions, N+, N2+, N3+ and N4+ ions. The fast electrons are simulated with a Monte Carlo model, whereas all other species are treated in a fluid model. 74 different chemical reactions are considered in the model. The calculation results include the densities of all the different plasma species, as well as information on their production and loss processes. The effect of different N2 additions, in the range between 0.1 and 10%, is investigated.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.241
Times cited: 49
DOI: 10.1016/j.sab.2008.11.004
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“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
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“CO 2 dissociation in a packed bed DBD reactor: First steps towards a better understanding of plasma catalysis”. Michielsen I, Uytdenhouwen Y, Pype J, Michielsen B, Mertens J, Reniers F, Meynen V, Bogaerts A, Chemical engineering journal 326, 477 (2017). http://doi.org/10.1016/j.cej.2017.05.177
Abstract: Plasma catalysis is gaining increasing interest for CO2 conversion, but the interaction between the plasma and catalyst is still poorly understood. This is caused by limited systematic materials research, since most works combine a plasma with commercial supported catalysts and packings. In the present paper, we study the influence of specific material and reactor properties, as well as reactor/bead configuration, on the conversion and energy efficiency of CO2 dissociation in a packed bed dielectric barrier discharge (DBD) reactor. Of the various packing materials investigated, BaTiO3 yields the highest conversion and energy efficiency, i.e., 25% and 4.5%.
Our results show that, when evaluating the influence of catalysts, the impact of the packing (support) material itself cannot be neglected, since it can largely affect the conversion and energy efficiency. This shows the large potential for further improvement of packed bed plasma reactors for CO2 conversion and other chemical conversion reactions by adjusting both packing (support) properties and catalytically active sites. Moreover, we clearly prove that comparison of results obtained in different reactor setups should be done with care, since there is a large effect of the reactor setup and reactor/bead configuration.
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: 49
DOI: 10.1016/j.cej.2017.05.177
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“Hydrogen addition to an argon glow discharge: a numerical simulation”. Bogaerts A, Journal of analytical atomic spectrometry 17, 768 (2002). http://doi.org/10.1039/b200025c
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.379
Times cited: 48
DOI: 10.1039/b200025c
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“Multiplicity and contiguity of ablation mechanisms in laser-assisted analytical micro-sampling”. Bleiner D, Bogaerts A, Spectrochimica acta: part B : atomic spectroscopy 61, 421 (2006). http://doi.org/10.1016/j.sab.2006.02.007
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.241
Times cited: 48
DOI: 10.1016/j.sab.2006.02.007
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“Atomic-scale simulations of reactive oxygen plasma species interacting with bacterial cell walls”. Yusupov M, Neyts EC, Khalilov U, Snoeckx R, van Duin ACT, Bogaerts A, New journal of physics 14, 093043 (2012). http://doi.org/10.1088/1367-2630/14/9/093043
Abstract: In recent years there has been growing interest in the use of low-temperature atmospheric pressure plasmas for biomedical applications. Currently, however, there is very little fundamental knowledge regarding the relevant interaction mechanisms of plasma species with living cells. In this paper, we investigate the interaction of important plasma species, such as O3, O2 and O atoms, with bacterial peptidoglycan (or murein) by means of reactive molecular dynamics simulations. Specifically, we use the peptidoglycan structure to model the gram-positive bacterium Staphylococcus aureus murein. Peptidoglycan is the outer protective barrier in bacteria and can therefore interact directly with plasma species. Our results demonstrate that among the species mentioned above, O3 molecules and especially O atoms can break important bonds of the peptidoglycan structure (i.e. CO, CN and CC bonds), which subsequently leads to the destruction of the bacterial cell wall. This study is important for gaining a fundamental insight into the chemical damaging mechanisms of the bacterial peptidoglycan structure on the atomic scale.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.786
Times cited: 47
DOI: 10.1088/1367-2630/14/9/093043
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“New pathways for nanoparticle formation in acetylene dusty plasmas: a modelling investigation and comparison with experiments”. Mao M, Benedikt J, Consoli A, Bogaerts A, Journal of physics: D: applied physics 41 (2008). http://doi.org/10.1088/0022-3727/41/22/225201
Abstract: In this paper, the initial mechanisms of nanoparticle formation and growth in radiofrequency acetylene (C2H2) plasmas are investigated by means of a comprehensive self-consistent one-dimensional (1D) fluid model. This model is an extension of the 1D fluid model, developed earlier by De Bleecker et al. Based on the comparison of our previous results with available experimental data for acetylene plasmas in the literature, some new mechanisms for negative ion formation and growth are proposed. Possible routes are considered for the formation of larger (linear and branched) hydrocarbons C2nH2 (n = 3, 4, 5), which contribute to the generation of C2nH− anions (n = 3, 4, 5) due to dissociative electron attachment. Moreover, the vinylidene anion (H2CC−) and higher anions (n = 24) are found to be important plasma species.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.588
Times cited: 47
DOI: 10.1088/0022-3727/41/22/225201
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“Modeling of CO2Splitting in a Microwave Plasma: How to Improve the Conversion and Energy Efficiency”. Berthelot A, Bogaerts A, The journal of physical chemistry: C : nanomaterials and interfaces 121, 8236 (2017). http://doi.org/10.1021/acs.jpcc.6b12840
Abstract: Microwave plasmas are one of the most promising techniques for CO2 conversion into value-added chemicals and fuels since they are very energy efficient. Nevertheless, experiments show that this high energy efficiency is only reached at low pressures and significantly drops toward atmospheric pressure, which is a clear limitation for industrial applications. In this paper, we use a zerodimensional reaction kinetics model to simulate a CO2 microwave plasma in a pressure range from 50 mbar to 1 bar, in order to evaluate the reasons for this decrease in energy efficiency at atmospheric pressure. The code includes a detailed description of the vibrational kinetics of CO2, CO, and O2 as well as the energy exchanges between them because the vibrational kinetics is known to be crucial for energy efficient CO2 splitting. First, we use a self-consistent gas temperature calculation in order to assess the key performance indicators for CO2 splitting, i.e., the CO2 conversion and corresponding energy efficiency. Our results indicate that lower pressures and higher power densities lead to more vibrational excitation, which is beneficial for the conversion. We also demonstrate the key role of the gas temperature. The model predicts the highest conversion and energy efficiencies at pressures around 300 mbar, which is in agreement with experiments from the literature. We also show the beneficial aspect of fast gas cooling in the afterglow at high pressure. In a second step, we study in more detail the effects of pressure, gas temperature, and power density on the vibrational distribution function and on the dissociation and recombination mechanisms of CO2, which define the CO2 splitting efficiency. This study allows us to identify the limiting factors of CO2 conversion and to propose potential solutions to improve the process.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.536
Times cited: 47
DOI: 10.1021/acs.jpcc.6b12840
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“Ab initio study of the spectroscopy, kinetics, and thermochemistry of the C2N and CN2 molecules”. Martin JML, Taylor PR, François JP, Gijbels R, Chemical physics letters 226, 475 (1994). http://doi.org/10.1016/0009-2614(94)00758-6
Abstract: Several structures and electronic states of the C2N and CN2 molecules have been studied using complete active space SCF (CASSCF), multireference configuration interaction (MRCI), and coupled cluster (CCSD(T)) methods. Both molecules are very stable. Our best computed total atomization energies SIGMAD(e) are 288.6 +/- 2 kcal/mol for CN2, and 294.1 +/- 2 kcal/mol for C2N. The CNC and CCN structures for C2N are nearly isoenergetic. CNN(3PI) lies about 30 kcal/mol above NCN(3PI(g)), but has a high barrier towards interconversion and is therefore observed experimentally. Computed harmonic frequencies for CNN are sensitive to the correlation treatment: they are reproduced well using multireference methods as well as the CCSD(T) method. High spin contamination has a detrimental effect on computed harmonic frequencies at the CCSD(T) level.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 1.897
Times cited: 46
DOI: 10.1016/0009-2614(94)00758-6
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“Asymmetric dyes align inside carbon nanotubes to yield a large nonlinear optical response”. Cambré, S, Campo J, Beirnaert C, Verlackt C, Cool P, Wenseleers W, Nature nanotechnology 10, 248 (2015). http://doi.org/10.1038/nnano.2015.1
Abstract: Asymmetric dye molecules have unusual optical and electronic properties1, 2, 3. For instance, they show a strong second-order nonlinear optical (NLO) response that has attracted great interest for potential applications in electro-optic modulators for optical telecommunications and in wavelength conversion of lasers2, 3. However, the strong Coulombic interaction between the large dipole moments of these molecules favours a pairwise antiparallel alignment that cancels out the NLO response when incorporated into bulk materials. Here, we show that by including an elongated dipolar dye (p,p′-dimethylaminonitrostilbene, DANS, a prototypical asymmetric dye with a strong NLO response4) inside single-walled carbon nanotubes (SWCNTs)5, 6, an ideal head-to-tail alignment in which all electric dipoles point in the same sense is naturally created. We have applied this concept to synthesize solution-processible DANS-filled SWCNTs that show an extremely large total dipole moment and static hyperpolarizability (β0 = 9,800 × 10−30 e.s.u.), resulting from the coherent alignment of arrays of ∼70 DANS molecules.
Keywords: A1 Journal article; Engineering sciences. Technology; Nanostructured and organic optical and electronic materials (NANOrOPT); Laboratory of adsorption and catalysis (LADCA); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 38.986
Times cited: 46
DOI: 10.1038/nnano.2015.1
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“Comprehensive description of a Grimm-type glow discharge source used for optical emission spectrometry: a mathematical simulation”. Bogaerts A, Gijbels R, Spectrochimica acta: part B : atomic spectroscopy 53, 437 (1998). http://doi.org/10.1016/S0584-8547(97)00148-1
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.241
Times cited: 46
DOI: 10.1016/S0584-8547(97)00148-1
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“An investigation into the dominant reactions for ethylene destruction in non-thermal atmospheric plasmas”. Aerts R, Tu X, De Bie C, Whitehead JC, Bogaerts A, Plasma processes and polymers 9, 994 (2012). http://doi.org/10.1002/ppap.201100168
Abstract: A crucial step, which is still not well understood in the destruction of volatile organic compounds (VOCs) with low temperature plasmas, is the initiation of the process. Here, we present a kinetic model for the destruction of ethylene in low temperature plasmas that allows us to calculate the relative importance of all plasma species and their related reactions. Modifying the ethylene concentration and/or the SED had a major impact on the relative importance of the radicals (i.e., mainly atomic oxygen) and the metastable nitrogen (i.e., more specifically N2(equation image)) in the destruction process. Our results show that the direct destruction by electron impact reactions for ethylene can be neglected; however, we can certainly not neglect the influence of N2(equation image)).
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.846
Times cited: 46
DOI: 10.1002/ppap.201100168
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“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
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“Single layer vs bilayer graphene : a comparative study of the effects of oxygen plasma treatment on their electronic and optical properties”. Nourbakhsh A, Cantoro M, Klekachev AV, Pourtois G, Vosch T, Hofkens J, van der Veen MH, Heyns MM, de Gendt S, Sels BF, The journal of physical chemistry: C : nanomaterials and interfaces 115, 16619 (2011). http://doi.org/10.1021/jp203010z
Abstract: This contribution presents the effects of a mild O2 plasma treatment on the structural, optical, and electrical properties of single-layer (SLG) and bilayer graphene (BLG). Unexpectedly, we observe only photoluminescence in the SLG parts of a graphene flake composed of regions of various thickness upon O2 plasma treatment, whereas the BLG and few-layer graphene (FLG) parts remain optically unchanged. Confirmed with X-ray photoelectron spectroscopy (XPS) that O2 plasma induces epoxide and hydroxyl-like groups in graphene, density functional theory (DFT) calculations are carried out on representative epoxidized and hydroxylated SLG and BLG models to predict density of states (DOS) and band structures. Sufficiently oxidized SLG shows a bandgap and thus loss of semimetallic behavior, while oxidized BLG maintains its semimetallic behavior even at high oxygen density in agreement with the results of the photoluminescence spectroscopy (PL) experiments. DFT calculations confirm that the Fermi velocity in epoxidized BLG is remarkably comparable with that of pristine SLG, pointing to a similarity of electronic band structure. The similarity is also experimentally demonstrated by the electrical characterization of a plasma-treated BLG-FET. As expected from the electronegative oxygen adatoms in the graphene, epoxidized BLG presents conductive features typical of hole doping. Moreover, the electrical characteristics suggest band structures closely related to that of epoxidized graphene while deviating from that of hydroxylated graphene. Finally, upon O2 plasma treatment of BLG, the four-component 2D peak around 2700 cm1 in the Raman spectrum evolves into a single Lorentzian line, very like the 2D peak of pristine SLG. Summarizing, the data in this contribution recommend that a controlled O2 plasma treatment, which is compatible with CMOS process flow in contrast to wet chemical oxidation methods, provides an efficient and valuable technique to exploit the transport properties of the bottom layer of BLG.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.536
Times cited: 46
DOI: 10.1021/jp203010z
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“Three-dimensional density profiles of sputtered atoms and ions in a direct current glow discharge: experimental study and comparison with calculations”. Bogaerts A, Wagner E, Smith BW, Winefordner JD, Pollmann D, Harrison WW, Gijbels R, Spectrochimica acta: part B : atomic spectroscopy 52, 205 (1997)
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.241
Times cited: 46
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“Hybrid modeling of a capacitively coupled radio frequency glow discharge in argon: combined Monte Carlo and fluid model”. Bogaerts A, Gijbels R, Goedheer W, Japanese journal of applied physics 38, 4404 (1999). http://doi.org/10.1143/JJAP.38.4404
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 1.384
Times cited: 45
DOI: 10.1143/JJAP.38.4404
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