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“Two-dimensional particle-in cell/Monte Carlo simulations of a packed-bed dielectric barrier discharge in air at atmospheric pressure”. Zhang Y, Wang H-yu, Jiang W, Bogaerts A, New journal of physics 17, 083056 (2015). http://doi.org/10.1088/1367-2630/17/8/083056
Abstract: The plasma behavior in a parallel-plate dielectric barrier discharge (DBD) is simulated by a two-dimensional particle-in-cell/Monte Carlo collision model, comparing for the first time an unpacked (empty) DBD with a packed bed DBD, i.e., a DBD filled with dielectric spheres in the gas gap. The calculations are performed in air, at atmospheric pressure. The discharge is powered by a pulse with a voltage amplitude of −20 kV. When comparing the packed and unpacked DBD reactors with the same dielectric barriers, it is clear that the presence of the dielectric packing leads to a transition in discharge behavior from a combination of negative streamers and unlimited surface streamers on the bottom dielectric surface to a combination of predominant positive streamers and limited surface discharges on the dielectric surfaces of the beads and plates. Furthermore, in the packed bed DBD, the electric field is locally enhanced inside the dielectric material, near the contact points between the beads and the plates, and therefore also in the plasma between the packing beads and between a bead and the dielectric wall, leading to values of $4\times {10}
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.786
Times cited: 22
DOI: 10.1088/1367-2630/17/8/083056
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“Laser-induced plasmas from the ablation of metallic targets: the problem of the onset temperature, and insights on the expansion dynamics”. Bleiner D, Bogaerts A, Belloni F, Nassisi V, Journal of applied physics 101, 083301 (2007). http://doi.org/10.1063/1.2721410
Abstract: Laser-induced plasmas are transient systems rapidly aging in few nanoseconds of evolution. Time-of-flight spectrometry allowed studying initial plasma characteristics based on frozen translational degrees of freedom, hence overcoming intrinsic limitations of optical spectroscopy. Experimental ion velocity distributions were reconstructed as developed during the longitudinal plasma expansion. The obtained onset plasma temperatures are in the range of similar to 18-45 eV depending on the ablated metals. Also the ion angular spreads were found to be a function of ablated metal, e.g., the narrowest for Fe, the broadest for Al, due to different collisional coupling in the plasma population. (c) 2007 American Institute of Physics.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.068
Times cited: 31
DOI: 10.1063/1.2721410
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“Routes to increase the conversion and the energy efficiency in the splitting of CO2by a dielectric barrier discharge”. Ozkan A, Bogaerts A, Reniers F, Journal of physics: D: applied physics 50, 084004 (2017). http://doi.org/10.1088/1361-6463/aa562c
Abstract: Here, we present routes to increase CO2 conversion into CO using an atmospheric pressure dielectric-barrier discharge. The change in conversion as a function of simple plasma parameters, such as power, flow rate, but also frequency, on-and-off power pulse, thickness and the chemical nature of the dielectric, wall and gas temperature, are described. By means of an in-depth electrical characterization of the discharge (effective plasma voltage, dielectric voltage, plasma current, number and lifetime of the microdischarges), combined with infrared analysis of the walls of the reactor, optical emission spectroscopy for the gas temperature, and mass spectrometry for the CO2 conversion, we propose a global interpretation of the effect of all the experimental parameters on the conversion and efficiency of the reaction.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.588
Times cited: 28
DOI: 10.1088/1361-6463/aa562c
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“How bead size and dielectric constant affect the plasma behaviour in a packed bed plasma reactor: a modelling study”. Van Laer K, Bogaerts A, Plasma sources science and technology 26, 085007 (2017). http://doi.org/10.1088/1361-6595/aa7c59
Abstract: Packed bed plasma reactors (PBPRs) are gaining increasing interest for use in environmental applications, such as greenhouse gas conversion into value-added chemicals or renewable fuels and volatile pollutant removal (e.g. NOx, VOC, K), as they enhance the conversion and energy efficiency of the process compared to a non-packed reactor. However, the plasma behaviour in a PBPR is not well understood. In this paper we demonstrate, by means of a fluid model, that the discharge behaviour changes considerably when changing the size of the packing beads and their dielectric constant, while keeping the interelectrode spacing constant. At low dielectric constant, the plasma is spread out over the full discharge gap, showing significant density in the voids as well as in the connecting void channels. The electric current profile shows a strong peak during each half cycle. When the dielectric constant increases, the plasma becomes localised in the voids, with a current profile consisting of many smaller peaks during each half cycle. For large bead sizes, the shift from full gap discharge to localised discharges takes place at a higher dielectric constant than for smaller beads. Furthermore, smaller beads or beads with a lower dielectric constant require a higher breakdown voltage to cause plasma formation.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.302
Times cited: 22
DOI: 10.1088/1361-6595/aa7c59
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“Numerical simulation on particle density and reaction pathways in methane needle-plane discharge plasma at atmospheric pressure”. Yue-Feng Z, Chao W, Wang W-Z, Li L, Hao S, Tao S, Jie P, Wuli xuebao 67, 085202 (2018). http://doi.org/10.7498/APS.67.20172192
Abstract: Methane needle-plane discharge has practical application prospect and scientific research significance since methane conversion heavy oil hydrogenation is formed by coupling methane needle-plane discharge with heavy oil hydrogenation, which can achieve high-efficient heavy oil hydrogenation and increase the yields of high value-added light olefins. In this paper, a two-dimensional fluid model is built up for numerically simulating the methane needle-plane discharge plasma at atmospheric pressure. Spatial and axial distributions of electric intensity, electron temperature and particle densities are obtained. Reaction yields are summarized and crucial pathways to produce various kinds of charged and neutral particles are found out. Simulation results indicate that axial evolutions of CH3+ and CH4+ densities, electric intensity and electron temperature are similar and closely related. The CH5+ and C2H5+ densities first increase and then decrease along the axial direction. The CH3 and H densities have nearly identical spatial and axial distributions. Particle density distributions of CH2, C2H4 and C2H5 are obviously different in the area near the cathode but comparatively resemblant in the positive column region. The CH3+ and CH4+ are produced by electron impact ionizations between electrons and CH4. The CH5+ and C2H5+ are respectively generated by molecular impact dissociations between CH3+ and CH4 and between CH4+ and CH4. Electron impact decomposition between electrons and CH4 is a dominated reaction to produce CH3, CH2, CH and H. The reactions between CH2 and CH4 and between electrons and C2H4 are critical pathways to produce C2H4 and C2H2, respectively. In addition, the yields of electron impact decomposition reactions between electrons and CH4 and reactions between CH2 and CH4 account for 52.15% and 47.85% of total yields of H-2 respectively.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 0.624
DOI: 10.7498/APS.67.20172192
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“The influence of impurities on the performance of the dielectric barrier discharge”. Martens T, Bogaerts A, Brok WJM, van Dijk J, Applied physics letters 96, 091501 (2010). http://doi.org/10.1063/1.3327800
Abstract: In this letter, we investigate the effect of various levels of nitrogen impurity on the electrical performance of an atmospheric pressure dielectric barrier discharge in helium. We illustrate the different current profiles that are obtained, which exhibit one or more discharge pulses per half cycle and evaluate their performance in ionizing the discharge and dissipating the power. It is shown that flat and broad current profiles perform the best in ionizing the discharge and use the least amount of power per generated charged particle.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.411
Times cited: 28
DOI: 10.1063/1.3327800
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“Identification of the ferroelectric switching process and dopant-dependent switching properties in orthorhombic HfO2 : a first principles insight”. Clima S, Wouters DJ, Adelmann C, Schenk T, Schroeder U, Jurczak M, Pourtois G, Applied physics letters 104, 092906 (2014). http://doi.org/10.1063/1.4867975
Abstract: The origin of the ferroelectric polarization switching in orthorhombic HfO2 has been investigated by first principles calculations. The phenomenon can be regarded as being the coordinated displacement of four O ions in the orthorhombic unit cell, which can lead to a saturated polarization as high as 53 mu C/cm(2). We show the correlation between the computed polarization reversal barrier and the experimental coercive fields. (C) 2014 AIP Publishing LLC.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.411
Times cited: 79
DOI: 10.1063/1.4867975
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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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“Calculation of gas heating in a dc sputter magnetron”. Kolev I, Bogaerts A, Journal of applied physics 104, 093301 (2008). http://doi.org/10.1063/1.2970166
Abstract: The effect of gas heating in laboratory sputter magnetrons is investigated by means of numerical modeling. The model is two-dimensional in the coordinate space and three-dimensional in the velocity space based on the particle-in-cellMonte Carlo collisions technique. It is expanded in a way that allows the inclusion of the neutral plasma particles (fast gas atoms and sputtered atoms), which makes it possible to calculate the gas temperature and its influence on the discharge behavior in a completely self-consistent way. The results of the model are compared to experimental measurements and to other existing simulation results. The results show that gas heating is pressure dependent (rising with the increase in the gas pressure) and should be taken into consideration at pressures above 10 mTorr.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.068
Times cited: 19
DOI: 10.1063/1.2970166
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“The role of UV photolysis and molecular transport in the generation of reactive species in a tissue model with a cold atmospheric pressure plasma jet”. Ghimire B, Szili EJ, Lamichhane P, Short RD, Lim JS, Attri P, Masur K, Weltmann K-D, Hong S-H, Choi EH, Applied physics letters 114, 093701 (2019). http://doi.org/10.1063/1.5086522
Abstract: Cold atmospheric pressure plasma jets (plasma) operated in ambient air provide a rich source of reactive oxygen and nitrogen species (RONS), which are known to influence biological processes important in disease. In the plasma treatment of diseased tissue such as subcutaneous cancer tumors, plasma RONS need to first traverse an interface between the plasma-skin surface and second be transported to millimeter depths in order to reach deep-seated diseased cells. However, the mechanisms in the plasma generation of RONS within soft tissues are not understood. In this study, we track the plasma jet delivery of RONS into a tissue model target and we delineate two processes: through target delivery of RONS generated (primarily) in the plasma jet and in situ RONS generation by UV photolysis within the target. We demonstrate that UV photolysis promotes the rapid generation of RONS in the tissue model target’s surface after which the RONS are transported to millimeter depths via a slower molecular process. Our results imply that the flux of UV photons from plasma jets is important for delivering RONS through seemingly impenetrable barriers such as skin. The findings have implications not only in treatments of living tissues but also in the functionalization of soft hydrated biomaterials such as hydrogels and extracellular matrix derived tissue scaffolds.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.411
Times cited: 12
DOI: 10.1063/1.5086522
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“Oscillatory behavior of the tunnel magnetoresistance due to thickness variations in Ta vertical bar CoFe vertical bar MgO magnetic tunnel junctions : a first-principles study”. Sankaran K, Swerts J, Couet S, Stokbro K, Pourtois G, Physical review B 94, 094424 (2016). http://doi.org/10.1103/PHYSREVB.94.094424
Abstract: To investigate the impact of both the CoFe ferromagnetic layer thickness and the capping paramagnetic layer on the tunnel magnetoresistance (TMR), we performed first-principles simulations on epitaxial magnetic tunnel junctions contacted with either CoFe or Ta paramagnetic capping layers. We observed a strong oscillation of the TMR amplitude with respect to the thickness of the ferromagnetic layer. The TMR is found to be amplified whenever the MgO spin tunnel barrier is thickened. Quantization of the electronic structure of the ferromagnetic layers is found to be at the origin of this oscillatory behavior. Metals such as Ta contacting the magnetic layer are found to enhance the amplitude of the oscillations due to the occurrence of an interface dipole. The latter drives the band alignment and tunes the nature of the spin channels that are active during the tunneling process. Subsequently, the regular transmission spin channels are modulated in the magnetic tunnel junction stack and other complex ones are being activated.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.836
Times cited: 4
DOI: 10.1103/PHYSREVB.94.094424
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“Short-pulse laser absorption in very steep plasma density gradients”. Cai H-bo, Yu W, Zhu S-ping, Zheng C-yang, Cao L-hua, Li B, Chen ZY, Bogaerts A, Physics of plasmas 13, 094504 (2006). http://doi.org/10.1063/1.2354583
Keywords: A1 Journal article; Condensed Matter Theory (CMT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.115
Times cited: 17
DOI: 10.1063/1.2354583
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“The effect of H2O on the vibrational populations of CO2in a CO2/H2O microwave plasma: a kinetic modelling investigation”. Verheyen C, Silva T, Guerra V, Bogaerts A, Plasma Sources Science &, Technology 29, 095009 (2020). http://doi.org/10.1088/1361-6595/aba1c8
Abstract: Plasma has been studied for several years to convert CO2 into value-added products. If CO2 could be converted in the presence of H2O as a cheap H-source for making syngas and oxygenates, it would mimic natural photosynthesis. However, CO2/H2O plasmas have not yet been extensively studied, not by experiments, and certainly not computationally. Therefore, we present here a kinetic modelling study to obtain a greater understanding of the vibrational kinetics of a CO2/H2O microwave plasma. For this purpose, we first created an electron impact cross section set for H2O, using a swarm-derived method. We added the new cross section set and CO2/H2O-related chemistry to a pure CO2 model. While it was expected that H2O addition mainly causes quenching of the CO2 asymmetric mode vibrational levels due to the additional CO2/H2O vibrational-translational relaxation, our model shows that the modifications in the vibrational kinetics are mainly induced by the strong electron dissociative attachment to H2O molecules, causing a reduction in electron density, and the corresponding changes in the input of energy into the CO2 vibrational levels by electron impact processes.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.8
DOI: 10.1088/1361-6595/aba1c8
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“The 2021 release of the Quantemol database (QDB) of plasma chemistries and reactions”. Tennyson J, Mohr S, Hanicinec M, Dzarasova A, Smith C, Waddington S, Liu B, Alves LL, Bartschat K, Bogaerts A, Engelmann SU, Gans T, Gibson AR, Hamaguchi S, Hamilton KR, Hill C, O’Connell D, Rauf S, van ’t Veer K, Zatsarinny O, Plasma Sources Science &, Technology 31, 095020 (2022). http://doi.org/10.1088/1361-6595/ac907e
Abstract: The Quantemol database (QDB) provides cross sections and rates of processes important for plasma models; heavy particle collisions (chemical reactions) and electron collision processes are considered. The current version of QDB has data on 28 917 processes between 2485 distinct species plus data for surface processes. These data are available via a web interface or can be delivered directly to plasma models using an application program interface; data are available in formats suitable for direct input into a variety of popular plasma modeling codes including HPEM, COMSOL, ChemKIN, CFD-ACE+, and VisGlow. QDB provides ready assembled plasma chemistries plus the ability to build bespoke chemistries. The database also provides a Boltzmann solver for electron dynamics and a zero-dimensional model. Thesedevelopments, use cases involving O<sub>2</sub>, Ar/NF<sub>3</sub>, Ar/NF<sub>3</sub>/O<sub>2</sub>, and He/H<sub>2</sub>O/O<sub>2</sub>chemistries, and plans for the future are presented.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.8
DOI: 10.1088/1361-6595/ac907e
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“Investigation of etching and deposition processes of Cl2/O2/Ar inductively coupled plasmas on silicon by means of plasmasurface simulations and experiments”. Tinck S, Boullart W, Bogaerts A, Journal of physics: D: applied physics 42, 095204 (2009). http://doi.org/10.1088/0022-3727/42/9/095204
Abstract: In this paper, a simulation method is described to predict the etching behaviour of Cl2/O2/Ar inductively coupled plasmas on a Si substrate, as used in shallow trench isolation for the production of electronic devices. The hybrid plasma equipment model (HPEM) developed by Kushner et al is applied to calculate the plasma characteristics in the reactor chamber and two additional Monte Carlo simulations are performed to predict the fluxes, angles and energy of the plasma species bombarding the Si substrate, as well as the resulting surface processes such as etching and deposition. The simulations are performed for a wide variety of operating conditions such as gas composition, chamber pressure, power deposition and substrate bias. It is predicted by the simulations that when the fraction of oxygen in the gas mixture is too high, the oxidation of the Si substrate is superior to the etching of Si by chlorine species, resulting in an etch rate close to zero as is also observed in the experiments.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.588
Times cited: 23
DOI: 10.1088/0022-3727/42/9/095204
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“Atomic level mechanisms of graphene healing by methane-based plasma radicals”. Khalilov U, Yusupov M, Eshonqulov Gb, Neyts Ec, Berdiyorov Gr, FlatChem 39, 100506 (2023). http://doi.org/10.1016/j.flatc.2023.100506
Keywords: A1 Journal article; Condensed Matter Theory (CMT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 6.2
DOI: 10.1016/j.flatc.2023.100506
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“Acquired non-thermal plasma resistance mediates a shift towards aerobic glycolysis and ferroptotic cell death in melanoma”. Lin A, Sahun M, Biscop E, Verswyvel H, De Waele J, De Backer J, Theys C, Cuypers B, Laukens K, Berghe WV, Smits E, Bogaerts A, Drug resistance updates 67, 100914 (2023). http://doi.org/10.1016/j.drup.2022.100914
Abstract: To gain insights into the underlying mechanisms of NTP therapy sensitivity and resistance, using the firstever
NTP-resistant cell line derived from sensitive melanoma cells (A375).
Methods: Melanoma cells were exposed to NTP and re-cultured for 12 consecutive weeks before evaluation
against the parental control cells. Whole transcriptome sequencing analysis was performed to identify differentially
expressed genes and enriched molecular pathways. Glucose uptake, extracellular lactate, media acidification,
and mitochondrial respiration was analyzed to determine metabolic changes. Cell death inhibitors were
used to assess the NTP-induced cell death mechanisms, and apoptosis and ferroptosis was further validated via
Annexin V, Caspase 3/7, and lipid peroxidation analysis.
Results: Cells continuously exposed to NTP became 10 times more resistant to NTP compared to the parental cell
line of the same passage, based on their half-maximal inhibitory concentration (IC50). Sequencing and metabolic
analysis indicated that NTP-resistant cells had a preference towards aerobic glycolysis, while cell death analysis
revealed that NTP-resistant cells exhibited less apoptosis but were more vulnerable to lipid peroxidation and
ferroptosis.
Conclusions: A preference towards aerobic glycolysis and ferroptotic cell death are key physiological changes in
NTP-resistance cells, which opens new avenues for further, in-depth research into other cancer types.
Keywords: A1 Journal article; Pharmacology. Therapy; ADReM Data Lab (ADReM); Center for Oncological Research (CORE); Proteinscience, proteomics and epigenetic signaling (PPES); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 24.3
DOI: 10.1016/j.drup.2022.100914
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“Plasma catalysis in ammonia production and decomposition: Use it, or lose it?”.Gorbanev Y, Fedirchyk I, Bogaerts A, Current Opinion in Green and Sustainable Chemistry 47, 100916 (2024). http://doi.org/10.1016/j.cogsc.2024.100916
Abstract: The combination of plasma with catalysis for the synthesis and decomposition of NH3 is an attractive route to the production of carbon-neutral fertiliser and energy carriers and its conversion into H2. Recent years have seen fast developments in the field of plasma-catalytic NH3 life cycle. This work summarises the most recent advances in plasma-catalytic and related NH3-focussed processes, identifies some of the most important discoveries, and addresses plausible strategies for future developments in plasma-based NH3 technology.
Keywords: A1 Journal Article; Plasma Nitrogen fixation Ammonia Plasma catalysis Production and decomposition; Plasma, laser ablation and surface modeling Antwerp (PLASMANT) ;
Impact Factor: 9.3
DOI: 10.1016/j.cogsc.2024.100916
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“Dual-vortex plasmatron: A novel plasma source for CO2 conversion”. Trenchev G, Bogaerts A, Journal Of Co2 Utilization 39, 101152 (2020). http://doi.org/10.1016/j.jcou.2020.03.002
Abstract: Atmospheric pressure gliding arc (GA) discharges are gaining increasing interest for CO2 conversion and other gas conversion applications, due to their simplicity and high energy efficiency. However, they are characterized by some drawbacks, such as non-uniform gas treatment, limiting the conversion, as well as the development of a hot cathode spot, resulting in severe electrode degradation. In this work, we built a dual-vortex plasmatron, which is a GA plasma reactor with innovative electrode configuration, to solve the above problems. The design aims to improve the CO2 conversion capability of the GA reactor by elongating the arc in two directions, to increase the residence time of the gas inside the arc, and to actively cool the cathode spot by rotation of the arc and gas convection. The measured CO2 conversion and corresponding energy efficiency indeed look very promising. In addition, we developed a fluid dynamics non-thermal plasma model with argon chemistry, to study the arc behavior in the reactor and to explain the experimental results.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 7.7
DOI: 10.1016/j.jcou.2020.03.002
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“Arc plasma reactor modification for enhancing performance of dry reforming of methane”. Dinh DK, Trenchev G, Lee DH, Bogaerts A, Journal Of Co2 Utilization 42, 101352 (2020). http://doi.org/10.1016/j.jcou.2020.101352
Abstract: Arc plasma technology is gaining increasing interest for a variety of chemical reaction applications. In this study, we demonstrate how modifying the reactor geometry can significantly enhance the chemical reaction performance. Using dry reforming of methane as a model reaction, we studied different rotating arc reactors (conventional rotating arc reactor and nozzle-type rotating arc reactor) to evaluate the effect of attaching a downstream nozzle. The nozzle structure focuses the heat to a confined reaction volume, resulting in enhanced heat transfer from the arc into gas activation and reduced heat losses to the reactor walls. Compared to the conventional rotating arc reactor, this yields much higher CH4 and CO2 conversion (i.e., 74% and 49%, respectively, versus 40% and 28% in the conventional reactor, at 5 kJ/L) as well as energy efficiency (i.e., 53% versus 36%). The different performance in both reactors was explained by both experiments (measurements of temperature and oscillogram of current and voltage) and numerical modelling of the gas flow dynamics, heat transfer and fluid plasma of the reactor chambers. The results provide important insights for design optimization of arc plasma reactors for various chemical reactions.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 7.7
DOI: 10.1016/j.jcou.2020.101352
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“Probing the impact of material properties of core-shell SiO₂@TiO₂, spheres on the plasma-catalytic CO₂, dissociation using a packed bed DBD plasma reactor”. Kaliyappan P, Paulus A, D’Haen J, Samyn P, Uytdenhouwen Y, Hafezkhiabani N, Bogaerts A, Meynen V, Elen K, Hardy A, Van Bael MK, Journal Of Co2 Utilization 46, 101468 (2021). http://doi.org/10.1016/J.JCOU.2021.101468
Abstract: Plasma catalysis, a promising technology for conversion of CO2 into value-added chemicals near room temperature, is gaining increasing interest. A dielectric barrier discharge (DBD) plasma has attracted attention due to its simple design and operation at near ambient conditions, ease to implement catalysts in the plasma zone and upscaling ability to industrial applications. To improve its main drawbacks, being relatively low conversion and energy efficiency, a packing material is used in the plasma discharge zone of the reactor, sometimes decorated by a catalytic material. Nevertheless, the extent to which different properties of the packing material influence plasma performance is still largely unexplored and unknown. In this study, the particular effect of synthesis induced differences in the morphology of a TiO2 shell covering a SiO2 core packing material on the plasma conversion of CO2 is studied. TiO2 has been successfully deposited around 1.6–1.8 mm sized SiO2 spheres by means of spray coating, starting from aqueous citratoperoxotitanate(IV) precursors. Parameters such as concentration of the Ti(IV) precursor solutions and addition of a binder were found to affect the shells’ properties and surface morphology and to have a major impact on the CO2 conversion in a packed bed DBD plasma reactor. Core-shell SiO2@TiO2 obtained from 0.25 M citratoperoxotitante(IV) precursors with the addition of a LUDOX binder showed the highest CO2 conversion 37.7% (at a space time of 70 s corresponding to an energy efficiency of 2%) and the highest energy efficiency of 4.8% (at a space time of 2.5 s corresponding to a conversion of 3%).
Keywords: A1 Journal article; Engineering sciences. Technology; Laboratory of adsorption and catalysis (LADCA); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.292
DOI: 10.1016/J.JCOU.2021.101468
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Van Alphen S, Slaets J, Ceulemans S, Aghaei M, Snyders R, Bogaerts A (2021) Effect of N2 on CO2-CH4 conversion in a gliding arc plasmatron: Can this major component in industrial emissions improve the energy efficiency? 101767
Abstract: Plasma-based CO2 and CH4 conversion is gaining increasing interest, and a great portion of research is dedicated to adapting the process to actual industrial conditions. In an industrial context, the process needs to be able to process N2 admixtures, since most industrial gas emissions contain significant amounts of N2, and gas separations are financially costly. In this paper we therefore investigate the effect of N2 on the CO2 and CH4 conversion in a gliding arc plasmatron reactor. The addition of 20 % N2 reduces the energy cost of the conversion process by 21 % compared to a pure CO2/CH4 mixture, from 2.9 down to 2.2 eV/molec (or from 11.5 to 8.7 kJ/L), yielding a CO2 and CH4 (absolute) conversion of 28.6 and 35.9 % and an energy efficiency of 58 %. These results are among the best reported in literature for plasma-based DRM, demonstrating the benefits of N2 present in the mix. Compared to DRM results in different plasma reactor types, a low energy cost was achieved. To understand the underlying mechanisms of N2 addition, we developed a combination of four different computational models, which reveal that the beneficial effect of N2 addition is attributed to (i) a rise in the electron density (increasing the plasma conductivity, and therefore reducing the plasma power needed to sustain the plasma, which reduces the energy cost), as well as (ii) a rise in the gas temperature, which accelerates the CO2 and CH4 conversion reactions.
Keywords: A1 Journal Article;Plasma-based CO2-CH4 conversion; Effect of N2; Plasma chemistry; Computational modelling; Gliding arc plasmatron; Plasma, laser ablation and surface modeling Antwerp (PLASMANT) ;
Impact Factor: 4.292
DOI: 10.1016/j.jcou.2021.101767
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“Dry reforming of methane in an atmospheric pressure glow discharge: Confining the plasma to expand the performance”. Wanten B, Maerivoet S, Vantomme C, Slaets J, Trenchev G, Bogaerts A, Journal Of Co2 Utilization 56, 101869 (2022). http://doi.org/10.1016/j.jcou.2021.101869
Abstract: We present a confined atmospheric pressure glow discharge plasma reactor, with very good performance towards dry reforming of methane, i.e., CO2 and CH4 conversion of 64 % and 94 %, respectively, at an energy cost of 3.5–4 eV/molecule (or 14–16 kJ/L). This excellent performance is among the best reported up to now for all types of plasma reactors in literature, and is due to the confinement of the plasma, which maximizes the fraction of gas passing through the active plasma region. The main product formed is syngas, with H2O and C2H2 as byproducts. We developed a quasi-1D chemical kinetics model, showing good agreement with the experimental results, which provides a thorough insight in the reaction pathways underlying the conversion of CO2 and CH4 and the formation of the different products.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 7.7
DOI: 10.1016/j.jcou.2021.101869
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“Oxidative damage to hyaluronan–CD44 interactions as an underlying mechanism of action of oxidative stress-inducing cancer therapy”. Yusupov M, Privat-Maldonado A, Cordeiro RM, Verswyvel H, Shaw P, Razzokov J, Smits E, Bogaerts A, Redox Biology 43, 101968 (2021). http://doi.org/10.1016/j.redox.2021.101968
Abstract: Multiple cancer therapies nowadays rely on oxidative stress to damage cancer cells. Here we investigated the biological and molecular effect of oxidative stress on the interaction between CD44 and hyaluronan (HA), as interrupting their binding can hinder cancer progression. Our experiments demonstrated that the oxidation of HA decreased its recognition by CD44, which was further enhanced when both CD44 and HA were oxidized. The reduction of CD44–HA binding negatively affected the proliferative state of cancer cells. Our multi-level atomistic simulations revealed that the binding free energy of HA to CD44 decreased upon oxidation. The effect of HA and CD44 oxidation on CD44–HA binding was similar, but when both HA and CD44 were oxidized, the effect was much larger, in agreement with our experiments. Hence, our experiments and computations support our hypothesis on the role of oxidation in the disturbance of CD44–HA interaction, which can lead to the inhibition of proliferative signaling pathways inside the tumor cell to induce cell death.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT); Center for Oncological Research (CORE)
Impact Factor: 6.337
DOI: 10.1016/j.redox.2021.101968
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“Editorial: Special issue on CO2 utilization with plasma technology”. Li S, Liu C, Bogaerts A, Gallucci F, Journal Of Co2 Utilization 61, 102017 (2022). http://doi.org/10.1016/j.jcou.2022.102017
Abstract: Plasma technology has advanced significantly in recent years, with application ranging from chemical conversion, to surface treatment, material development and several other fields. Special attention has been paid to the development of possible novel approaches for the conversion of chemicals in a more sustainable way. Plasma technology offers advantages over thermochemical routes such as high process versatility, mild reaction condition, one-step synthesis, fast reaction and instant control. More importantly, it can be easily combined with electricity generated from various renewable sources and is suitable for energy storage via the conversion of intermittent renewable energy into carbon-neutral fuels or other chemicals. In recent years, there has been a growing interest in the development of plasma technology for CO2 utilization. Investigation on different reactions such as CO2 splitting, dry reforming of methane (DRM) and CO2 hydrogenation with different types of plasma reactors and catalysts have been reported by researchers worldwide. Although technological maturity still needs to be increased, the potential of plasma has been well-recognized by the scientific community and industry. More research output in the future is expected as a result of intensive research activities and various kinds of investment. In this context, we present this special issue on CO2 utilization with plasma technology, which collects 22 articles, covering topics in related areas such as plasma reactor design, plasma catalysis, plasmamaterial interaction, modeling and new ideas for possible applications.
Keywords: Editorial; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 7.7
DOI: 10.1016/j.jcou.2022.102017
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“Enhancing CO2 conversion with plasma reactors in series and O2 removal”. Vertongen R, Trenchev G, Van Loenhout R, Bogaerts A, Journal Of Co2 Utilization 66, 102252 (2022). http://doi.org/10.1016/j.jcou.2022.102252
Abstract: In this work, we take a crucial step towards the industrial readiness of plasma-based CO2 conversion. We present a stepwise method to study plasma reactors in series as a first approach to a recycle flow. By means of this procedure, the CO2 conversion is enhanced by a factor of 3, demonstrating that a single-pass plasma treatment performs far below the optimal capacity of the reactor. Furthermore, we explore the effect of O2 in the mixture with our flexible procedure. Addition of O2 in the mixture has a clear detrimental effect on the conversion, in agreement with other experiments in atmospheric pressure plasmas. O2 removal is however highly beneficial, demonstrating a conversion per pass that is 1.6 times higher than the standard procedure. Indeed, extracting one of the products prevents recombination reactions. Based on these insights, we discuss opportunities for further improvements, especially in the field of specialised separation techniques.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 7.7
DOI: 10.1016/j.jcou.2022.102252
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Ivanov V, Paunska T, Lazarova S, Bogaerts A, Kolev S (2023) Gliding arc/glow discharge for CO2 conversion: Comparing the performance of different discharge configurations. 102300
Abstract: We studied the use of low current (hundreds of milliamperes) gliding arc/glow discharges for CO2 dissociation, at atmospheric pressure, in three different configurations. All of these are based on the gliding arc design with flat diverging electrodes. The discharge is mainly in the normal glow regime with contracted positive column. The CO2 gas is injected from a nozzle, at the closest separation between the electrodes. A pair of quartz glasses is placed on both sides of the electrodes, so that the gas flow is restricted to the active plasma area, between the electrodes. For two of the tested configurations, an external magnetic field was applied, to create a magnetic force, both in the direction of the gas flow, and opposite to the gas flow. In the first case, the arc is accelerated, shortening the period between ignition and extinction, while in the second case, it is stabilized (magneticallystabilized). We studied two quantities, namely the CO2 conversion and the energy efficiency of the conversion. Generally, the CO2 conversion decreases with increasing flow rate and increases with power. The energy efficiency increases with the flow rate, for all configurations. The magnetically-stabilized configuration is more stable and efficient at low gas flow rates, but has poor performance at high flow rates, while the non-stabilized configurations exhibit good conversion for a larger range of flow rates, but they are generally more unstable and less efficient.
Keywords: A1 Journal Article;CO2 conversion; CO2 dissociation; Low current gliding arc; Magnetic stabilization; Magnetically stabilized discharge; Gliding glow discharge; Plasma, laser ablation and surface modeling Antwerp (PLASMANT) ;
Impact Factor: 7.7
DOI: 10.1016/j.jcou.2022.102300
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“Atomic oxygen assisted CO2 conversion: A theoretical analysis”. Verheyen C, van ’t Veer K, Snyders R, Bogaerts A, Journal of CO2 utilization 67, 102347 (2023). http://doi.org/10.1016/j.jcou.2022.102347
Abstract: With climate change still a pressing issue, there is a great need for carbon capture, utilisation and storage (CCUS)
methods. We propose a novel concept where CO2 conversion is accomplished by O2 splitting followed by the
addition of O atoms to CO2. The latter is studied here by means of kinetic modelling. In the first instance, we
study various CO2/O ratios, and we observe an optimal CO2 conversion of around 30–40% for 50% O addition.
Gas temperature also has a large influence, with a minimum temperature of around 1000 K to a maximum of
2000 K for optimal conversion. In the second instance, we study various CO2/O/O2 ratios, due to O2 being a
starting gas. Also here we define optimal regions for CO2 conversion, which reach maximum conversion for a
CO2 fraction of 50% and an O/O2 ratio bigger than 1. Those can be expanded by heating on one hand, for low
atomic oxygen availability, and by quenching after reaction on the other hand, for cases where the temperatures
are too high. Our model predictions can serve as a guideline for experimental research in this domain.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 7.7
DOI: 10.1016/j.jcou.2022.102347
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“Cytoglobin inhibits non-thermal plasma-induced apoptosis in melanoma cells through regulation of the NRF2-mediated antioxidant response”. De Backer J, Lin A, Berghe WV, Bogaerts A, Hoogewijs D, Redox Biology 55, 102399 (2022). http://doi.org/10.1016/j.redox.2022.102399
Abstract: Melanoma arises from pigment-producing cells called melanocytes located in the basal layers of the epidermis of the skin. Cytoglobin (CYGB) is a ubiquitously expressed hexacoordinated globin that is highly enriched in melanocytes and frequently downregulated during melanomagenesis. Previously, we showed that non-thermal plasma (NTP)-produced reactive oxygen and nitrogen species (RONS) lead to the formation of an intra molecular disulfide bridge that would allow CYGB to function as a redox-sensitive protein. Here, we investigate the cytotoxic effect of indirect NTP treatment in two melanoma cell lines with divergent endogenous CYGB expression levels, and we explore the role of CYGB in determining treatment outcome. Our findings are consistent with previous studies supporting that NTP cytotoxicity is mediated through the production of RONS and leads to apoptotic cell death in melanoma cells. Furthermore, we show that NTP-treated solutions elicit an antioxidant response through the activation of nuclear factor erythroid 2–related factor 2 (NRF2). The knock down and overexpression of CYGB respectively sensitizes and protects melanoma cells from RONS-induced apoptotic cell death. The presence of CYGB enhances heme-oxygenase 1 (HO-1) and NRF2 protein expression levels, whereas the absence impairs their expression. Moreover, analysis of the CYGB-dependent transcriptome demonstrates the tumor suppressor long non-coding RNA maternally expressed 3 (MEG3) as a hitherto unde scribed link between CYGB and NRF2. Thus, the presence of CYGB, at least in melanoma cells, seems to play a central role in determining the therapeutic outcome of RONS-inducing anticancer therapies, like NTP-treated solutions, possessing both tumor-suppressive and oncogenic features. Hence, CYGB expression could be of in terest either as a biomarker or as a candidate for future targeted therapies in melanoma.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT); Proteinscience, proteomics and epigenetic signaling (PPES)
Impact Factor: 11.4
DOI: 10.1016/j.redox.2022.102399
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“The pro- and anti-tumoral properties of gap junctions in cancer and their role in therapeutic strategies”. Oliveira MC, Verswyvel H, Smits E, Cordeiro RM, Bogaerts A, Lin A, Redox Biology 57, 102503 (2022). http://doi.org/10.1016/j.redox.2022.102503
Abstract: Gap junctions (GJs), essential structures for cell-cell communication, are made of two hemichannels (commonly called connexons), one on each adjacent cell. Found in almost all cells, GJs play a pivotal role in many physiological and cellular processes, and have even been linked to the progression of diseases, such as cancer. Modulation of GJs is under investigation as a therapeutic strategy to kill tumor cells. Furthermore, GJs have also been studied for their key role in activating anti-cancer immunity and propagating radiation- and oxidative stress-induced cell death to neighboring cells, a process known as the bystander effect. While, gap junction (GJ)based therapeutic strategies are being developed, one major challenge has been the paradoxical role of GJs in both tumor progression and suppression, based on GJ composition, cancer factors, and tumoral context. Therefore, understanding the mechanisms of action, regulation, and the dual characteristics of GJs in cancer is critical for developing effective therapeutics. In this review, we provide an overview of the current under standing of GJs structure, function, and paradoxical pro- and anti-tumoral role in cancer. We also discuss the treatment strategies to target these GJs properties for anti-cancer responses, via modulation of GJ function.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT); Center for Oncological Research (CORE)
Impact Factor: 11.4
DOI: 10.1016/j.redox.2022.102503
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