“Merging Metadynamics into Hyperdynamics: Accelerated Molecular Simulations Reaching Time Scales from Microseconds to Seconds”. Bal KM, Neyts EC, Journal of chemical theory and computation 11, 4545 (2015). http://doi.org/10.1021/acs.jctc.5b00597
Abstract: The hyperdynamics method is a powerful tool to simulate slow processes at the atomic level. However, the construction of an optimal hyperdynamics potential is a task that is far from trivial. Here, we propose a generally applicable implementation of the hyperdynamics algorithm, borrowing two concepts from metadynamics. First, the use of a collective variable (CV) to represent the accelerated dynamics gives the method a very large flexibility and simplicity. Second, a metadynamics procedure can be used to construct a suitable history-dependent bias potential on-the-fly, effectively turning the algorithm into a self-learning accelerated molecular dynamics method. This collective variable-driven hyperdynamics (CVHD) method has a modular design: both the local system properties on which the bias is based, as well as the characteristics of the biasing method itself, can be chosen to match the needs of the considered system. As a result, system-specific details are abstracted from the biasing algorithm itself, making it extremely versatile and transparent. The method is tested on three model systems: diffusion on the Cu(001) surface and nickel-catalyzed methane decomposition, as examples of reactive processes with a bond-length-based CV, and the folding of a long polymer-like chain, using a set of dihedral angles as a CV. Boost factors up to 109, corresponding to a time scale of seconds, could be obtained while still accurately reproducing correct dynamics.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 5.245
Times cited: 41
DOI: 10.1021/acs.jctc.5b00597
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“SBH17 : benchmark database of barrier heights for dissociative chemisorption on transition metal surfaces”. Tchakoua T, Gerrits N, Smeets EWF, Kroes G-J, Journal of chemical theory and computation 19, 245 (2023). http://doi.org/10.1021/ACS.JCTC.2C00824
Abstract: Accurate barriers for rate controlling elementary reactions on metal surfaces are key to understanding, controlling, and predicting the rate of heterogeneously catalyzed processes. While barrier heights for gas phase reactions have been extensively benchmarked, dissociative chemisorption barriers for the reactions of molecules on metal surfaces have received much less attention. The first database called SBH10 and containing 10 entries was recently constructed based on the specific reaction parameter approach to density functional theory (SRP-DFT) and experimental results. We have now constructed a new and improved database (SBH17) containing 17 entries based on SRP-DFT and experiments. For this new SBH17 benchmark study, we have tested three algorithms (high, medium, and light) for calculating barrier heights for dissociative chemisorption on metals, which we have named for the amount of computational effort involved in their use. We test the performance of 14 density functionals at the GGA, GGA+vdW-DF, and meta-GGA rungs. Our results show that, in contrast with the previous SBH10 study where the BEEF-vdW-DF2 functional seemed to be most accurate, the workhorse functional PBE and the MS2 density functional are the most accurate of the GGA and meta-GGA functionals tested. Of the GGA+vdW functionals tested, the SRP32-vdW-DF1 functional is the most accurate. Additionally, we found that the medium algorithm is accurate enough for assessing the performance of the density functionals tested, while it avoids geometry optimizations of minimum barrier geometries for each density functional tested. The medium algorithm does require metal lattice constants and interlayer distances that are optimized separately for each functional. While these are avoided in the light algorithm, this algorithm is found not to give a reliable description of functional performance. The combination of relative ease of use and demonstrated reliability of the medium algorithm will likely pave the way for incorporation of the SBH17 database in larger databases used for testing new density functionals and electronic structure methods.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 5.5
DOI: 10.1021/ACS.JCTC.2C00824
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“Reweighted Jarzynski sampling : acceleration of rare events and free energy calculation with a bias potential learned from nonequilibrium work”. Bal KM, Journal Of Chemical Theory And Computation 17, 6766 (2021). http://doi.org/10.1021/ACS.JCTC.1C00574
Abstract: We introduce a simple enhanced sampling approach for the calculation of free energy differences and barriers along a one-dimensional reaction coordinate. First, a small number of short nonequilibrium simulations are carried out along the reaction coordinate, and the Jarzynski equality is used to learn an approximate free energy surface from the nonequilibrium work distribution. This free energy estimate is represented in a compact form as an artificial neural network and used as an external bias potential to accelerate rare events in a subsequent molecular dynamics simulation. The final free energy estimate is then obtained by reweighting the equilibrium probability distribution of the reaction coordinate sampled under the influence of the external bias. We apply our reweighted Jarzynski sampling recipe to four processes of varying scales and complexities.spanning chemical reaction in the gas phase, pair association in solution, and droplet nucleation in supersaturated vapor. In all cases, we find reweighted Jarzynski sampling to be a very efficient strategy, resulting in rapid convergence of the free energy to high precision.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 5.245
DOI: 10.1021/ACS.JCTC.1C00574
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“CO2-CH4 conversion and syngas formation at atmospheric pressure using a multi-electrode dielectric barrier discharge”. Ozkan A, Dufour T, Arnoult G, De Keyzer P, Bogaerts A, Reniers F, Journal of CO2 utilization 9, 74 (2015). http://doi.org/10.1016/j.jcou.2015.01.002
Abstract: The conversion of CO2 and CH4 into value-added chemicals is studied in a new geometry of a dielectric barrier discharge (DBD) with multi-electrodes, dedicated to the treatment of high gas flow rates. Gas chromatography is used to define the CO2 and CH4 conversion as well as the yields of the products of decomposition (CO, O2 and H2) and of recombination (C2H4, C2H6 and CH2O). The influence of three parameters is investigated on the conversion: the CO2 and CH4 flow rates, the plasma power and the nature of the carrier gas (argon or helium). The energy efficiency of the CO2 conversion is estimated and compared with those of similar atmospheric plasma sources. Our DBD reactor shows a good compromise between a good energy efficiency and the treatment of a large CO2 flow rate.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.292
Times cited: 57
DOI: 10.1016/j.jcou.2015.01.002
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“CO2 conversion in a gliding arc plasma: Performance improvement based on chemical reaction modeling”. Sun SR, Wang HX, Mei DH, Tu X, Bogaerts A, Journal of CO2 utilization 17, 220 (2017). http://doi.org/10.1016/j.jcou.2016.12.009
Abstract: CO2 conversion into value-added chemicals is gaining increasing interest in recent years, and a gliding arc plasma has great potential for this purpose, because of its high energy efficiency. In this study, a chemical reaction kinetics model is presented to study the CO2 splitting in a gliding arc discharge. The calculated
conversion and energy efficiency are in good agreement with experimental data in a range of different operating conditions. Therefore, this reaction kinetics model can be used to elucidate the dominant chemical reactions contributing to CO2 destruction and formation. Based on this reaction pathway analysis, the restricting factors for CO2 conversion are figured out, i.e., the reverse reactions and the small treated gas fraction. This allows us to propose some solutions in order to improve the CO2 conversion, such as decreasing the gas temperature, by using a high frequency discharge, or increasing the power
density, by using a micro-scale gliding arc reactor, or by removing the reverse reactions, which could be realized in practice by adding possible scavengers for O atoms, such as CH4. Finally, we compare our results with other types of plasmas in terms of conversion and energy efficiency, and the results illustrate that gliding arc discharges are indeed quite promising for CO2 conversion, certainly when keeping in mind the possible solutions for further performance improvement.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.292
Times cited: 41
DOI: 10.1016/j.jcou.2016.12.009
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“Pinpointing energy losses in CO 2 plasmas &ndash, Effect on CO 2 conversion”. Berthelot A, Bogaerts A, Journal of CO2 utilization 24, 479 (2018). http://doi.org/10.1016/j.jcou.2018.02.011
Abstract: Plasma technology is gaining increasing interest for CO2 conversion, but to maximize the energy efficiency, it is important to track the different energy transfers taking place in the plasma. In this paper, we study these mechanisms by a 0D chemical kinetics model, including the vibrational kinetics, for different conditions of reduced electric field, gas temperature and ionization degree, at a pressure of 100 mbar. Our model predicts a maximum conversion and energy efficiency of 32% and 47%, respectively, at conditions that are particularly beneficial for energy efficient CO2 conversion, i.e. a low reduced electric field (10 Td) and a low gas temperature (300 K). We study the effect of the efficiency by which the vibrational energy is used to dissociate CO2, as well as of the activation energy of the reaction CO2+O→CO+O2, to elucidate the theoretical limitations to the energy
efficiency. Our model reveals that these parameters are mainly responsible for the limitations in the energy efficiency. By varying these parameters, we can reach a maximum conversion and energy efficiency of 86%. Finally, we derive an empirical formula to estimate the maximum possible energy efficiency that can be reached under the assumptions of the model.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.292
Times cited: 6
DOI: 10.1016/j.jcou.2018.02.011
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“Carbon dioxide dissociation in a microwave plasma reactor operating in a wide pressure range and different gas inlet configurations”. Belov I, Vermeiren V, Paulussen S, Bogaerts A, Journal of CO2 utilization 24, 386 (2018). http://doi.org/10.1016/j.jcou.2017.12.009
Abstract: Microwave (MW) plasmas represent a promising solution for efficient CO2 dissociation. MW discharges are also very versatile and can be sustained at various pressure and gas flow regimes. To identify the most favorable conditions for the further scale-up of the CO2 decomposition reaction, a MW plasma reactor operating in pure CO2 in a wide pressure range (200 mbar–1 bar) is studied. Three different gas flow configurations are explored: a direct, reverse and a vortex regime. The CO2 conversion and energy efficiency drop almost linearly with increasing pressure, regardless of the gas flow regime. The results obtained in the direct flow configuration underline the importance of post-discharge cooling, as the exhaust of the MW plasma reactor in this regime expanded into the vacuum chamber without additional quenching. As a result, this system yields exhaust temperatures of up to 1000 K, which explains the lowest conversion (∼3.5% at 200 mbar and 2% at 1 bar). A post-discharge cooling step is introduced for the reverse gas inlet regime and allows the highest conversion to be achieved (∼38% at 200 mbar and 6.2% at 1 bar, with energy efficiencies of 23% and 3.7%). Finally, a tangential gas inlet is utilized in the vortex configuration to generate a swirl flow pattern. This results in the generation of a stable discharge in a broader range of CO2 flows (15–30 SLM) and the highest energy efficiencies obtained in this study (∼25% at 300 mbar and ∼13% at 1 bar, at conversions of 21% and 12%). The experimental results are complemented with computational fluid dynamics simulations and with the analysis of the latest literature to identify the further research directions.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.292
Times cited: 8
DOI: 10.1016/j.jcou.2017.12.009
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“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
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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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“Plasma-based conversion of martian atmosphere into life-sustaining chemicals: The benefits of utilizing martian ambient pressure”. Kelly S, Mercer E, Gorbanev Y, Fedirchyk I, Verheyen C, Werner K, Pullumbi P, Cowley A, Bogaerts A, Journal of CO2 utilization 80, 102668 (2024). http://doi.org/10.1016/j.jcou.2024.102668
Abstract: We explored the potential of plasma-based In-Situ Resource Utilization (ISRU) for Mars through the conversion of Martian atmosphere (~96% CO2, 2% N2, and 2% Ar) into life-sustaining chemicals. As the Martian surface pressure is about 1% of the Earth’s surface pressure, it is an ideal environment for plasma-based gas conversion using microwave reactors. At 1000 W and 10 Ln/min (normal liters per minute), we produced ~76 g/h of O2 and ~3 g/h of NOx using a 2.45 GHz waveguided reactor at 25 mbar, which is ~3.5 times Mars ambient pressure. The energy cost required to produce O2 was ~0.013 kWh/g, which is very promising compared to recently concluded MOXIE experiments on the Mars surface. This marks a crucial step towards realizing the extension of human exploration.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 7.7
DOI: 10.1016/j.jcou.2024.102668
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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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“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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“How important is reactor design for CO2 conversion in warm plasmas?”.Vertongen R, Bogaerts A, Journal of CO2 Utilization 72, 102510 (2023). http://doi.org/10.1016/j.jcou.2023.102510
Abstract: In this work, we evaluated several new electrode configurations for CO2 conversion in a gliding arc plasmatron
(GAP) reactor. Although the reactor design influences the performance, the best results give only slightly higher
CO2 conversion than the basic GAP reactor design, which indicates that this reactor may have reached its performance
limits. Moreover, we compared our results to those of four completely different plasma reactors, also
operating at atmospheric pressure and with contact between the plasma and the electrodes. Surprisingly, the
performance of all these warm plasmas is very similar (CO2 conversion around 10 % for an energy efficiency
around 30 %). In view of these apparent performance limits regarding the reactor design, we believe further
improvements should focus on other aspects, such as the post-plasma-region where the implementation of
nozzles or a carbon bed are promising. We summarize the performance of our GAP reactor by comparing the
energy efficiency and CO2 conversion for all different plasma reactors reported in literature. We can conclude
that the GAP is not the best plasma reactor, but its operation at atmospheric pressure makes it appealing for
industrial application. We believe that future efforts should focus on process design, techno-economic assessments
and large-scale demonstrations: these will be crucial to assess the real industrial potential of this warm
plasma technology
Keywords: A1 Journal Article; Plasma, laser ablation and surface modeling Antwerp (PLASMANT) ;
Impact Factor: 7.7
DOI: 10.1016/j.jcou.2023.102510
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“Microwave plasma-based dry reforming of methane: Reaction performance and carbon formation”. Kelly S, Mercer E, De Meyer R, Ciocarlan R-G, Bals S, Bogaerts A, Journal of CO2 utilization 75, 102564 (2023). http://doi.org/10.1016/j.jcou.2023.102564
Abstract: e investigate atmospheric pressure microwave (MW) plasma (2.45 GHz) conversion in CO2 and CH4 mixtures (i.e., dry reforming of methane, DRM) focusing on reaction performance and carbon formation. Promising energy costs of ~2.8–3.0 eV/molecule or ~11.1–11.9 kJ/L are amongst the best performance to date considering the current state-of-the-art for plasma-based DRM for all types of plasma. The conversion is in the range of ~46–49% and ~55–67% for CO2 and CH4, respectively, producing primarily syngas (i.e., H2 and CO) with H2/CO ratios of ~0.6–1 at CH4 fractions ranging from 30% to 45%. Water is the largest byproduct with levels ranging ~7–14% in the exhaust. Carbon particles visibly impact the plasma at higher CH4 fractions (> 30%), where they become heated and incandescent. Particle luminosity increases with increasing CH4 fractions, with the plasma becoming unstable near a 1:1 mixture (i.e., > 45% CH4). Electron microscopy of the carbon material reveals an agglomerated morphology of pure carbon nanoparticles. The mean particle size is determined as ~20 nm, free of any metal contamination, consistent with the electrode-less MW design.
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: 7.7
Times cited: 6
DOI: 10.1016/j.jcou.2023.102564
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“Improving the performance of gliding arc plasma-catalytic dry reforming via a new post-plasma tubular catalyst bed”. Xu W, Buelens LC, Galvita VV, Bogaerts A, Meynen V, Journal of CO2 Utilization 83, 102820 (2024). http://doi.org/10.1016/j.jcou.2024.102820
Abstract: A combination of a gliding arc plasmatron (GAP) reactor and a newly designed tubular catalyst bed (N-bed) was applied to investigate the post-plasma catalytic (PPC) effect for dry reforming of methane (DRM). As comparison, a traditional plasma catalyst bed (T-bed) was also utilized. The post-plasma catalytic effect of a Ni-based mixed oxide (Ni/MO) catalyst with a thermal catalytic performance of 77% CO2 and 86% CH4 conversion at 700 ℃ was studied. Although applying the T-bed had little effect on plasma based CO2 and CH4 conversion, an increase in selectivity to H2 was obtained with a maximum value of 89% at a distance of 2 cm. However, even when only α-Al2O3 packing material was used in the N-bed configuration, compared to the plasma alone and the T-bed, an increase of the CO2 and CH4 conversion from 53% and 53% to 69% and 69% to 83% was achieved. Addition of the Ni/MO catalyst further enhanced the DRM reaction, resulting in conversions of 79% for CO2 and 91% for
CH4. Hence, although no insulation nor external heating was applied to the N-bed post plasma, it provides a slightly better conversion than the thermal catalytic performance with the same catalyst, while being fully electrically driven. In addition, an enhanced CO selectivity to 96% was obtained and the energy cost was reduced from ~ 6 kJ/L (plasma alone) to 4.3 kJ/L. To our knowledge, it is the first time that a post-plasma catalytic system achieves this excellent catalytic performance for DRM without extra external heating or insulation.
Keywords: A1 Journal Article; Dry reforming Gliding arc plasma Plasma catalytic DRM Ni-based mixed oxide Post-plasma catalysis; Plasma, laser ablation and surface modeling Antwerp (PLASMANT) ;
Impact Factor: 7.7
DOI: 10.1016/j.jcou.2024.102820
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“A critical comparison of MINDO/3, MNDO, AM1 and PM3 for a model problem: carbon clusters C2-C10. An ad hoc reparametrization of MNDO well suited for the accurate prediction of their spectroscopic constants”. Martin JML, François JP, Gijbels R, Journal of computational chemistry 12, 52 (1991)
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.589
Times cited: 76
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“Analytical and self-consistent quantum mechanical model for a surrounding gate MOS nanowire operated in JFET mode”. Sorée B, Magnus W, Pourtois G, Journal of computational electronics 7, 380 (2008). http://doi.org/10.1007/s10825-008-0217-3
Abstract: We derive an analytical model for the electrostatics and the drive current in a silicon nanowire operating in JFET mode. We show that there exists a range of nanowire radii and doping densities for which the nanowire JFET satisfies reasonable device characteristics. For thin nanowires we have developed a self-consistent quantum mechanical model to obtain the electronic structure.
Keywords: A1 Journal article; Condensed Matter Theory (CMT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 1.526
Times cited: 70
DOI: 10.1007/s10825-008-0217-3
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“Kinetic and thermodynamic heterogeneity : an intrinsic source of variability in Cu-based RRAM memories”. Clima S, Belmonte A, Degraeve R, Fantini A, Goux L, Govoreanu B, Jurczak M, Ota K, Redolfi A, Kar GS, Pourtois G, Journal of computational electronics 16, 1011 (2017). http://doi.org/10.1007/S10825-017-1042-3
Abstract: <script type='text/javascript'>document.write(unpmarked('The resistive random-access memory (RRAM) device concept is close to enabling the development of a new generation of non-volatile memories, provided that their reliability issues are properly understood. The design of a RRAM operating with extrinsic defects based on metallic inclusions, also called conductive bridge RAM, allows the use of a large spectrum of solid electrolytes. However, when scaled to device dimensions that meet the requirements of the latest technological nodes, the discrete nature of the atomic structure of the materials impacts the device operation. Using density functional theory simulations, we evaluated the migration kinetics of Cu conducting species in amorphous and solid electrolyte materials, and established that atomic disorder leads to a large variability in terms of defect stability and kinetic barriers. This variability has a significant impact on the filament resistance and its dynamics, as evidenced during the formation step of the resistive filament. Also, the atomic configuration of the formed filament can age/relax to another metastable atomic configuration, and lead to a modulation of the resistivity of the filament. All these observations are qualitatively explained on the basis of the computed statistical distributions of the defect stability and on the kinetic barriers encountered in RRAM materials.'));
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 1.526
Times cited: 2
DOI: 10.1007/S10825-017-1042-3
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“Effect of chemical modification on electronic transport properties of carbyne”. Berdiyorov GR, Khalilov U, Hamoudi H, Neyts EC, Journal Of Computational Electronics (2021). http://doi.org/10.1007/s10825-020-01639-7
Abstract: Using density functional theory in combination with the Green’s functional formalism, we study the effect of surface functionalization on the electronic transport properties of 1D carbon allotrope—carbyne. We found that both hydrogenation and fluorination result in structural changes and semiconducting to metallic transition. Consequently, the current in the functionalization systems increases significantly due to strong delocalization of electronic states along the carbon chain. We also study the electronic transport in partially hydrogenated carbyne and interface structures consisting of pristine and functionalized carbyne. In the latter case, current rectification is obtained in the system with rectification ratio up to 50%. These findings can be useful for developing carbyne-based structures with tunable electronic transport properties.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 1.526
DOI: 10.1007/s10825-020-01639-7
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“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
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“Study of the nucleation and growth of TiO2 and ZnO thin films by means of molecular dynamics simulations”. Baguer N, Georgieva V, Calderin L, Todorov IT, van Gils S, Bogaerts A, Journal of crystal growth 311, 4034 (2009). http://doi.org/10.1016/j.jcrysgro.2009.06.034
Abstract: The nucleation and growth of titanium dioxide (TiO2) and zinc oxide (ZnO) thin films on Fe2O3 (hematite), Al2O3 (á-alumina) and SiO2 (á-quartz) are studied by molecular dynamics simulations. The results show the formation of a strong interface region between the substrate and the film in the six systems studied here. A combination of polycrystalline and amorphous phases are observed in the TiO2 films grown on the three substrates. ZnO deposition on the Fe2O3 and Al2O3 crystals yields a monocrystalline film growth. The ZnO film deposited on the SiO2 crystal exhibits less crystallinity. The simulation results are compared with experimental results available in the literature.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 1.751
Times cited: 23
DOI: 10.1016/j.jcrysgro.2009.06.034
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“Is a catalyst always beneficial in plasma catalysis? Insights from the many physical and chemical interactions”. Loenders B, Michiels R, Bogaerts A, Journal of Energy Chemistry 85, 501 (2023). http://doi.org/10.1016/j.jechem.2023.06.016
Abstract: Plasma-catalytic dry reforming of CH4 (DRM) is promising to convert the greenhouse gasses CH4 and CO2 into value-added chemicals, thus simultaneously providing an alternative to fossil resources as feedstock for the chemical industry. However, while many experiments have been dedicated to plasma-catalytic DRM, there is no consensus yet in literature on the optimal choice of catalyst for targeted products, because the underlying mechanisms are far from understood. Indeed, plasma catalysis is very complex, as it encompasses various chemical and physical interactions between plasma and catalyst, which depend on many parameters. This complexity hampers the comparison of experimental results from different studies, which, in our opinion, is an important bottleneck in the further development of this promising research field. Hence, in this perspective paper, we describe the important physical and chemical effects that should be accounted for when designing plasma-catalytic experiments in general, highlighting the need for standardized experimental setups, as well as careful documentation of packing properties and reaction conditions, to further advance this research field. On the other hand, many parameters also create many windows of opportunity for further optimizing plasma-catalytic systems. Finally, various experiments also reveal the lack of improvement in plasma catalysis compared to plasma-only, specifically for DRM, but the underlying mechanisms are unclear. Therefore, we present our newly developed coupled plasma-surface kinetics model for DRM, to provide more insight in the underlying reasons. Our model illustrates that transition metal catalysts can adversely affect plasmacatalytic DRM, if radicals dominate the plasma-catalyst interactions. Thus, we demonstrate that a good understanding of the plasma-catalyst interactions is crucial to avoiding conditions at which these interactions negatively affect the results, and we provide some recommendations for improvement. For instance, we believe that plasma-catalytic DRM may benefit more from higher reaction temperatures, at which vibrational excitation can enhance the surface reactions.
Keywords: A1 Journal Article; Plasma, laser ablation and surface modeling Antwerp (PLASMANT) ;
Impact Factor: 13.1
DOI: 10.1016/j.jechem.2023.06.016
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“Plasma-based CO2 conversion: How to correctly analyze the performance?”.Wanten B, Vertongen R, De Meyer R, Bogaerts A, Journal of Energy Chemistry 86, 180 (2023). http://doi.org/10.1016/j.jechem.2023.07.005
Keywords: A1 journal article; Plasma, laser ablation and surface modeling Antwerp (PLASMANT) ;
Impact Factor: 13.1
DOI: 10.1016/j.jechem.2023.07.005
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“Meta-analysis of CO₂, conversion, energy efficiency, and other performance data of plasma-catalysis reactors with the open access PIONEER database”. Salden A, Budde M, Garcia-Soto CA, Biondo O, Barauna J, Faedda M, Musig B, Fromentin C, Nguyen-Quang M, Philpott H, Hasrack G, Aceto D, Cai Y, Jury FA, Bogaerts A, Da Costa P, Engeln R, Galvez ME, Gans T, Garcia T, Guerra V, Henriques C, Motak M, Navarro MV, Parvulescu VI, Van Rooij G, Samojeden B, Sobota A, Tosi P, Tu X, Guaitella O, Journal of energy chemistry 86, 318 (2023). http://doi.org/10.1016/J.JECHEM.2023.07.022
Abstract: This paper brings the comparison of performances of CO2 conversion by plasma and plasma-assisted catalysis based on the data collected from literature in this field, organised in an open access online data-base. This tool is open to all users to carry out their own analyses, but also to contributors who wish to add their data to the database in order to improve the relevance of the comparisons made, and ultimately to improve the efficiency of CO2 conversion by plasma-catalysis. The creation of this database and data-base user interface is motivated by the fact that plasma-catalysis is a fast-growing field for all CO2 con-version processes, be it methanation, dry reforming of methane, methanolisation, or others. As a result of this rapid increase, there is a need for a set of standard procedures to rigorously compare performances of different systems. However, this is currently not possible because the fundamental mechanisms of plasma-catalysis are still too poorly understood to define these standard procedures. Fortunately how-ever, the accumulated data within the CO2 plasma-catalysis community has become large enough to war-rant so-called “big data” studies more familiar in the fields of medicine and the social sciences. To enable comparisons between multiple data sets and make future research more effective, this work proposes the first database on CO2 conversion performances by plasma-catalysis open to the whole community. This database has been initiated in the framework of a H2020 European project and is called the “PIONEER DataBase”. The database gathers a large amount of CO2 conversion performance data such as conversion rate, energy efficiency, and selectivity for numerous plasma sources coupled with or without a catalyst. Each data set is associated with metadata describing the gas mixture, the plasma source, the nature of the catalyst, and the form of coupling with the plasma. Beyond the database itself, a data extraction tool with direct visualisation features or advanced filtering functionalities has been developed and is available online to the public. The simple and fast visualisation of the state of the art puts new results into context, identifies literal gaps in data, and consequently points towards promising research routes. More advanced data extraction illustrates the impact that the database can have in the understanding of plasma-catalyst coupling. Lessons learned from the review of a large amount of literature during the setup of the database lead to best practice advice to increase comparability between future CO2 plasma-catalytic studies. Finally, the community is strongly encouraged to contribute to the database not only to increase the visibility of their data but also the relevance of the comparisons allowed by this tool. (c) 2023 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. This is an open access article under the CC BY license (http://creati- vecommons.org/licenses/by/4.0/).
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 13.1
DOI: 10.1016/J.JECHEM.2023.07.022
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