Plasma Catalysis

A special issue of Catalysts (ISSN 2073-4344). This special issue belongs to the section "Environmental Catalysis".

Deadline for manuscript submissions: closed (30 November 2018) | Viewed by 82226

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Department of Chemistry, University of Antwerp, Campus Drie Eiken – Room B2.09, Universiteitsplein 1, Wilrijk, BE-2610 Antwerp, Belgium
Interests: plasma and plasma–surface interactions by means of computer modeling and experiments, for various applications, with a major focus on green chemistry; plasma catalysis
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Dear Colleagues,

Plasma catalysis is gaining increasing interest for various gas conversion applications, such as CO2 conversion into value-added chemicals and fuels, N2 fixation for the synthesis of NH3 or NOx, methane conversion into higher hydrocarbons or oxygenates. It is also widely used for air pollution control (e.g., VOC  remediation). Plasma catalysis allows thermodynamically difficult reactions to proceed at ambient pressure and temperature, due to activation of the gas molecules by energetic electrons created in the plasma. However, plasma is very reactive but not selective, and thus a catalyst is needed to improve the selectivity.

In spite of the growing interest in plasma catalysis, the underlying mechanisms of the (possible) synergy between plasma and catalyst are not yet fully understood. Indeed, plasma catalysis is quite complicated, as the plasma will affect the catalyst and vice versa. Moreover, due to the reactive plasma environment, the most suitable catalysts will probably be different from thermal catalysts. More research is needed to better understand the plasma–catalyst interactions, in order to further improve the applications.

Submissions to this Special Issue are welcome in the form of original research papers or short reviews that reflect the state of the art in the above-mentioned applications.  

Prof. Dr. Annemie Bogaerts
Guest Editor

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Keywords

  • Plasma–catalyst interaction
  • CO2 conversion
  • N2 fixation
  • CH4 conversion
  • Air pollution control
  • Plasma catalysis synergy
  • Plasma reactor
  • Dielectric barrier discharge
  • Ambient conditions

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Published Papers (13 papers)

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Editorial

Jump to: Research, Review

5 pages, 184 KiB  
Editorial
Editorial Catalysts: Special Issue on Plasma Catalysis
by Annemie Bogaerts
Catalysts 2019, 9(2), 196; https://doi.org/10.3390/catal9020196 - 21 Feb 2019
Cited by 6 | Viewed by 4256
Abstract
Plasma catalysis is gaining increasing interest for various gas conversion applications, such as CO2 conversion into value-added chemicals and fuels, N2 fixation for the synthesis of NH3 or NOx, and CH4 conversion into higher hydrocarbons or oxygenates [...] Full article
(This article belongs to the Special Issue Plasma Catalysis)

Research

Jump to: Editorial, Review

25 pages, 15013 KiB  
Article
Plasma Catalysis: Distinguishing between Thermal and Chemical Effects
by Guido Giammaria, Gerard van Rooij and Leon Lefferts
Catalysts 2019, 9(2), 185; https://doi.org/10.3390/catal9020185 - 16 Feb 2019
Cited by 21 | Viewed by 5836
Abstract
The goal of this study is to develop a method to distinguish between plasma chemistry and thermal effects in a Dielectric Barrier Discharge nonequilibrium plasma containing a packed bed of porous particles. Decomposition of CaCO3 in Ar plasma is used as a [...] Read more.
The goal of this study is to develop a method to distinguish between plasma chemistry and thermal effects in a Dielectric Barrier Discharge nonequilibrium plasma containing a packed bed of porous particles. Decomposition of CaCO3 in Ar plasma is used as a model reaction and CaCO3 samples were prepared with different external surface area, via the particle size, as well as with different internal surface area, via pore morphology. Also, the effect of the CO2 in gas phase on the formation of products during plasma enhanced decomposition is measured. The internal surface area is not exposed to plasma and relates to thermal effect only, whereas both plasma and thermal effects occur at the external surface area. Decomposition rates were in our case found to be influenced by internal surface changes only and thermal decomposition is concluded to dominate. This is further supported by the slow response in the CO2 concentration at a timescale of typically 1 minute upon changes in discharge power. The thermal effect is estimated based on the kinetics of the CaCO3 decomposition, resulting in a temperature increase within 80 °C for plasma power from 0 to 6 W. In contrast, CO2 dissociation to CO and O2 is controlled by plasma chemistry as this reaction is thermodynamically impossible without plasma, in agreement with fast response within a few seconds of the CO concentration when changing plasma power. CO forms exclusively via consecutive dissociation of CO2 in the gas phase and not directly from CaCO3. In ongoing work, this methodology is used to distinguish between thermal effects and plasma–chemical effects in more reactive plasma, containing, e.g., H2. Full article
(This article belongs to the Special Issue Plasma Catalysis)
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13 pages, 4868 KiB  
Communication
Highly Dispersed Co Nanoparticles Prepared by an Improved Method for Plasma-Driven NH3 Decomposition to Produce H2
by Li Wang, YanHui Yi, HongChen Guo, XiaoMin Du, Bin Zhu and YiMin Zhu
Catalysts 2019, 9(2), 107; https://doi.org/10.3390/catal9020107 - 22 Jan 2019
Cited by 33 | Viewed by 4492
Abstract
Previous studies reveal that combining non-thermal plasma with cheap metal catalysts achieved a significant synergy of enhancing performance of NH3 decomposition, and this synergy strongly depended on the properties of the catalyst used. In this study, techniques of vacuum-freeze drying and plasma [...] Read more.
Previous studies reveal that combining non-thermal plasma with cheap metal catalysts achieved a significant synergy of enhancing performance of NH3 decomposition, and this synergy strongly depended on the properties of the catalyst used. In this study, techniques of vacuum-freeze drying and plasma calcination were employed to improve the conventional preparation method of catalyst, aiming to enhance the activity of plasma-catalytic NH3 decomposition. Compared with the activity of the catalyst prepared by a conventional method, the conversion of NH3 significantly increased by 47% when Co/fumed SiO2 was prepared by the improved method, and the energy efficiency of H2 production increased from 2.3 to 5.7 mol(kW·h)−1 as well. So far, the highest energy efficiency of H2 formation of 15.9 mol(kW·h)−1 was achieved on improved prepared Co/fumed SiO2 with 98.0% ammonia conversion at the optimal conditions. The improved preparation method enables cobalt species to be highly dispersed on fumed SiO2 support, which creates more active sites. Besides, interaction of Co with fumed SiO2 and acidity of the catalyst were strengthened according to results of H2-TPR and NH3-probe experiments, respectively. These results demonstrate that employing vacuum-freeze drying and plasma calcination during catalyst preparation is an effective approach to manipulate the properties of catalyst, and enables the catalyst to display high activity towards plasma-catalytic NH3 decomposition to produce H2. Full article
(This article belongs to the Special Issue Plasma Catalysis)
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22 pages, 11296 KiB  
Article
High-Efficiency Catalytic Conversion of NOx by the Synergy of Nanocatalyst and Plasma: Effect of Mn-Based Bimetallic Active Species
by Yan Gao, Wenchao Jiang, Tao Luan, Hui Li, Wenke Zhang, Wenchen Feng and Haolin Jiang
Catalysts 2019, 9(1), 103; https://doi.org/10.3390/catal9010103 - 18 Jan 2019
Cited by 20 | Viewed by 5434
Abstract
Three typical Mn-based bimetallic nanocatalysts of Mn−Fe/TiO2, Mn−Co/TiO2, Mn−Ce/TiO2 were synthesized via the hydrothermal method to reveal the synergistic effects of dielectric barrier discharge (DBD) plasma and bimetallic nanocatalysts on NOx catalytic conversion. The plasma-catalyst hybrid catalysis [...] Read more.
Three typical Mn-based bimetallic nanocatalysts of Mn−Fe/TiO2, Mn−Co/TiO2, Mn−Ce/TiO2 were synthesized via the hydrothermal method to reveal the synergistic effects of dielectric barrier discharge (DBD) plasma and bimetallic nanocatalysts on NOx catalytic conversion. The plasma-catalyst hybrid catalysis was investigated compared with the catalytic effects of plasma alone and nanocatalyst alone. During the catalytic process of catalyst alone, the catalytic activities of all tested catalysts were lower than 20% at ambient temperature. While in the plasma-catalyst hybrid catalytic process, NOx conversion significantly improved with discharge energy enlarging. The maximum NOx conversion of about 99.5% achieved over Mn−Ce/TiO2 under discharge energy of 15 W·h/m3 at ambient temperature. The reaction temperature had an inhibiting effect on plasma-catalyst hybrid catalysis. Among these three Mn-based bimetallic nanocatalysts, Mn−Ce/TiO2 displayed the optimal catalytic property with higher catalytic activity and superior selectivity in the plasma-catalyst hybrid catalytic process. Furthermore, the physicochemical properties of these three typical Mn-based bimetallic nanocatalysts were analyzed by N2 adsorption, Transmission Electron Microscope (TEM), X-ray diffraction (XRD), H2-temperature-programmed reduction (TPR), NH3-temperature-programmed desorption (TPD), and X-ray photoelectron spectroscopy (XPS). The multiple characterizations demonstrated that the plasma-catalyst hybrid catalytic performance was highly dependent on the phase compositions. Mn−Ce/TiO2 nanocatalyst presented the optimal structure characteristic among all tested samples, with the largest surface area, the minished particle sizes, the reduced crystallinity, and the increased active components distributions. In the meantime, the ratios of Mn4+/(Mn2+ + Mn3+ + Mn4+) in the Mn−Ce/TiO2 sample was the highest, which was beneficial to plasma-catalyst hybrid catalysis. Generally, it was verified that the plasma-catalyst hybrid catalytic process with the Mn-based bimetallic nanocatalysts was an effective approach for high-efficiency catalytic conversion of NOx, especially at ambient temperature. Full article
(This article belongs to the Special Issue Plasma Catalysis)
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32 pages, 3915 KiB  
Article
Altering Conversion and Product Selectivity of Dry Reforming of Methane in a Dielectric Barrier Discharge by Changing the Dielectric Packing Material
by Inne Michielsen, Yannick Uytdenhouwen, Annemie Bogaerts and Vera Meynen
Catalysts 2019, 9(1), 51; https://doi.org/10.3390/catal9010051 - 7 Jan 2019
Cited by 41 | Viewed by 5792 | Correction
Abstract
We studied the influence of dense, spherical packing materials, with different chemical compositions, on the dry reforming of methane (DRM) in a dielectric barrier discharge (DBD) reactor. Although not catalytically activated, a vast effect on the conversion and product selectivity could already be [...] Read more.
We studied the influence of dense, spherical packing materials, with different chemical compositions, on the dry reforming of methane (DRM) in a dielectric barrier discharge (DBD) reactor. Although not catalytically activated, a vast effect on the conversion and product selectivity could already be observed, an influence which is often neglected when catalytically activated plasma packing materials are being studied. The α-Al2O3 packing material of 2.0–2.24 mm size yields the highest total conversion (28%), as well as CO2 (23%) and CH4 (33%) conversion and a high product fraction towards CO (~70%) and ethane (~14%), together with an enhanced CO/H2 ratio of 9 in a 4.5 mm gap DBD at 60 W and 23 kHz. γ-Al2O3 is only slightly less active in total conversion (22%) but is even more selective in products formed than α-Al2O3. BaTiO3 produces substantially more oxygenated products than the other packing materials but is the least selective in product fractions and has a clear negative impact on CO2 conversion upon addition of CH4. Interestingly, when comparing to pure CO2 splitting and when evaluating differences in products formed, significantly different trends are obtained for the packing materials, indicating a complex impact of the presence of CH4 and the specific nature of the packing materials on the DRM process. Full article
(This article belongs to the Special Issue Plasma Catalysis)
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12 pages, 1267 KiB  
Article
Isotope Labelling for Reaction Mechanism Analysis in DBD Plasma Processes
by Paula Navascués, Jose M. Obrero-Pérez, José Cotrino, Agustín R. González-Elipe and Ana Gómez-Ramírez
Catalysts 2019, 9(1), 45; https://doi.org/10.3390/catal9010045 - 4 Jan 2019
Cited by 15 | Viewed by 4182
Abstract
Dielectric barrier discharge (DBD) plasmas and plasma catalysis are becoming an alternative procedure to activate various gas phase reactions. A low-temperature and normal operating pressure are the main advantages of these processes, but a limited energy efficiency and little selectivity control hinder their [...] Read more.
Dielectric barrier discharge (DBD) plasmas and plasma catalysis are becoming an alternative procedure to activate various gas phase reactions. A low-temperature and normal operating pressure are the main advantages of these processes, but a limited energy efficiency and little selectivity control hinder their practical implementation. In this work, we propose the use of isotope labelling to retrieve information about the intermediate reactions that may intervene during the DBD processes contributing to a decrease in their energy efficiency. The results are shown for the wet reforming reaction of methane, using D2O instead of H2O as reactant, and for the ammonia synthesis, using NH3/D2/N2 mixtures. In the two cases, it was found that a significant amount of outlet gas molecules, either reactants or products, have deuterium in their structure (e.g., HD for hydrogen, CDxHy for methane, or NDxHy for ammonia). From the analysis of the evolution of the labelled molecules as a function of power, useful information has been obtained about the exchange events of H by D atoms (or vice versa) between the plasma intermediate species. An evaluation of the number of these events revealed a significant progression with the plasma power, a tendency that is recognized to be detrimental for the energy efficiency of reactant to product transformation. The labelling technique is proposed as a useful approach for the analysis of plasma reaction mechanisms. Full article
(This article belongs to the Special Issue Plasma Catalysis)
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20 pages, 9155 KiB  
Article
Destruction of Toluene, Naphthalene and Phenanthrene as Model Tar Compounds in a Modified Rotating Gliding Arc Discharge Reactor
by Xiangzhi Kong, Hao Zhang, Xiaodong Li, Ruiyang Xu, Ishrat Mubeen, Li Li and Jianhua Yan
Catalysts 2019, 9(1), 19; https://doi.org/10.3390/catal9010019 - 28 Dec 2018
Cited by 22 | Viewed by 4947
Abstract
Tar removal is one of the greatest technical challenges of commercial gasification technologies. To find an efficient way to destroy tar with plasma, a rotating gliding arc (RGA) discharge reactor equipped with a fan-shaped swirling generator was used for model tar destruction in [...] Read more.
Tar removal is one of the greatest technical challenges of commercial gasification technologies. To find an efficient way to destroy tar with plasma, a rotating gliding arc (RGA) discharge reactor equipped with a fan-shaped swirling generator was used for model tar destruction in this study. The solution of toluene, naphthalene and phenanthrene is used as a tar surrogate and is destroyed in humid nitrogen. The influence of tar, CO2 and moisture concentrations, and the discharge current on the destruction efficiency is emphasized. In addition, the combination of Ni/γ-Al2O3 catalyst with plasma was tested for plasma catalytic tar destruction. The toluene, naphthalene and phenanthrene destruction efficiency reached up to 95.2%, 88.9%, and 83.9% respectively, with a content of 12 g/Nm3 tar, 12% moisture, 15% CO2, and a flow rate of 6 NL/min, whereas 9.3 g/kW·h energy efficiency was achieved. The increase of discharge current is advantageous in terms of decreasing black carbon production. The participation of Ni/γ-Al2O3 catalyst shows considerable improvement in destruction efficiency, especially at a relatively high flow rate (over 9 NL/min). The major liquid by-products are phenylethyne, indene, acenaphthylene and fluoranthene. The first two are majorly converted from toluene, acenaphthylene is produced by the co-reaction of toluene and naphthalene in the plasma, and fluoranthene is converted by phenanthrene. Full article
(This article belongs to the Special Issue Plasma Catalysis)
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10 pages, 1428 KiB  
Article
Ammonia Plasma-Catalytic Synthesis Using Low Melting Point Alloys
by Javishk R. Shah, Joshua M. Harrison and Maria L. Carreon
Catalysts 2018, 8(10), 437; https://doi.org/10.3390/catal8100437 - 3 Oct 2018
Cited by 38 | Viewed by 6890
Abstract
The Haber-Bosch process has been the commercial benchmark process for ammonia synthesis for more than a century. Plasma-catalytic synthesis for ammonia production is theorized to have a great potential for being a greener alternative to the Haber-Bosch process. However, the underlying reactions for [...] Read more.
The Haber-Bosch process has been the commercial benchmark process for ammonia synthesis for more than a century. Plasma-catalytic synthesis for ammonia production is theorized to have a great potential for being a greener alternative to the Haber-Bosch process. However, the underlying reactions for ammonia synthesis still require some detailed study especially for radiofrequency plasmas. Herein, the use of inductively coupled radiofrequency plasma for the synthesis of ammonia when employing Ga, In and their alloys as catalysts is presented. The plasma is characterized using emission spectroscopy and the surface of catalysts using Scanning Electron Microscope. A maximum energy yield of 0.31 g-NH3/kWh and energy cost of 196 MJ/mol is achieved with Ga-In (0.6:0.4 and 0.2:0.8) alloy at 50 W plasma power. Granular nodes are observed on the surface of catalysts indicating the formation of the intermediate GaN. Full article
(This article belongs to the Special Issue Plasma Catalysis)
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13 pages, 1894 KiB  
Article
Plasma Oxidation of H2S over Non-stoichiometric LaxMnO3 Perovskite Catalysts in a Dielectric Barrier Discharge Reactor
by Kejie Xuan, Xinbo Zhu, Yuxiang Cai and Xin Tu
Catalysts 2018, 8(8), 317; https://doi.org/10.3390/catal8080317 - 2 Aug 2018
Cited by 21 | Viewed by 4929
Abstract
In this work, plasma-catalytic removal of H2S over LaxMnO3 (x = 0.90, 0.95, 1, 1.05 and 1.10) has been studied in a coaxial dielectric barrier discharge (DBD) reactor. The non-stoichiometric effect of the LaxMnO3 [...] Read more.
In this work, plasma-catalytic removal of H2S over LaxMnO3 (x = 0.90, 0.95, 1, 1.05 and 1.10) has been studied in a coaxial dielectric barrier discharge (DBD) reactor. The non-stoichiometric effect of the LaxMnO3 catalysts on the removal of H2S and sulfur balance in the plasma-catalytic process has been investigated as a function of specific energy density (SED). The integration of the plasma with the LaxMnO3 catalysts significantly enhanced the reaction performance compared to the process using plasma alone. The highest H2S removal of 96.4% and sulfur balance of 90.5% were achieved over the La0.90MnO3 catalyst, while the major products included SO2 and SO3. The missing sulfur could be ascribed to the sulfur deposited on the catalyst surfaces. The non-stoichiometric LaxMnO3 catalyst exhibited larger specific surface areas and smaller crystallite sizes compared to the LaMnO3 catalyst. The non-stoichiometric effect changed their redox properties as the decreased La/Mn ratio favored the transformation of Mn3+ to Mn4+, which contributed to the generation of oxygen vacancies on the catalyst surfaces. The XPS and H2-TPR results confirmed that the Mn-rich catalysts showed the higher relative concentration of surface adsorbed oxygen (Oads) and lower reduction temperature compared to LaMnO3 catalyst. The reaction performance of the plasma-catalytic oxidation of H2S is closely related to the relative concentration of Oads formed on the catalyst surfaces and the reducibility of the catalysts. Full article
(This article belongs to the Special Issue Plasma Catalysis)
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15 pages, 1871 KiB  
Article
Plasma-Catalytic Mineralization of Toluene Adsorbed on CeO2
by Zixian Jia, Xianjie Wang, Emeric Foucher, Frederic Thevenet and Antoine Rousseau
Catalysts 2018, 8(8), 303; https://doi.org/10.3390/catal8080303 - 27 Jul 2018
Cited by 12 | Viewed by 4338
Abstract
In the context of coupling nonthermal plasmas with catalytic materials, CeO2 is used as adsorbent for toluene and combined with plasma for toluene oxidation. Two configurations are addressed for the regeneration of toluene saturated CeO2: (i) in plasma-catalysis (IPC); and [...] Read more.
In the context of coupling nonthermal plasmas with catalytic materials, CeO2 is used as adsorbent for toluene and combined with plasma for toluene oxidation. Two configurations are addressed for the regeneration of toluene saturated CeO2: (i) in plasma-catalysis (IPC); and (ii) post plasma-catalysis (PPC). As an advanced oxidation technique, the performances of toluene mineralization by the plasma-catalytic systems are evaluated and compared through the formation of CO2. First, the adsorption of 100 ppm of toluene onto CeO2 is characterized in detail. Total, reversible and irreversible adsorbed fractions are quantified. Specific attention is paid to the influence of relative humidity (RH): (i) on the adsorption of toluene on CeO2; and (ii) on the formation of ozone in IPC and PPC reactors. Then, the mineralization yield and the mineralization efficiency of adsorbed toluene are defined and investigated as a function of the specific input energy (SIE). Under these conditions, IPC and PPC reactors are compared. Interestingly, the highest mineralization yield and efficiency are achieved using the in-situ configuration operated with the lowest SIE, that is, lean conditions of ozone. Based on these results, the specific impact of RH on the IPC treatment of toluene adsorbed on CeO2 is addressed. Taking into account the impact of RH on toluene adsorption and ozone production, it is evidenced that the mineralization of toluene adsorbed on CeO2 is directly controlled by the amount of ozone produced by the discharge and decomposed on the surface of the coupling material. Results highlight the key role of ozone in the mineralization process and the possible detrimental effect of moisture. Full article
(This article belongs to the Special Issue Plasma Catalysis)
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11 pages, 3151 KiB  
Article
DBD Plasma-ZrO2 Catalytic Decomposition of CO2 at Low Temperatures
by Amin Zhou, Dong Chen, Cunhua Ma, Feng Yu and Bin Dai
Catalysts 2018, 8(7), 256; https://doi.org/10.3390/catal8070256 - 23 Jun 2018
Cited by 45 | Viewed by 6291
Abstract
This study describes the decomposition of CO2 using Dielectric Barrier Discharge (DBD) plasma technology combined with the packing materials. A self-cooling coaxial cylinder DBD reactor that packed ZrO2 pellets or glass beads with a grain size of 1–2 mm was designed [...] Read more.
This study describes the decomposition of CO2 using Dielectric Barrier Discharge (DBD) plasma technology combined with the packing materials. A self-cooling coaxial cylinder DBD reactor that packed ZrO2 pellets or glass beads with a grain size of 1–2 mm was designed to decompose CO2. The control of the temperature of the reactor was achieved via passing the condensate water through the shell of the DBD reactor. Key factors, for instance discharge length, packing materials, beads size and discharge power, were investigated to evaluate the efficiency of CO2 decomposition. The results indicated that packing materials exhibited a prominent effect on CO2 decomposition, especially in the presence of ZrO2 pellets. Most encouragingly, a maximum decomposition rate of 49.1% (2-mm particle sizes) and 52.1% (1-mm particle sizes) was obtained with packing ZrO2 pellets and a 32.3% (2-mm particle sizes) and a 33.5% (1-mm particle sizes) decomposing rate with packing glass beads. In the meantime, CO selectivity was up to 95%. Furthermore, the energy efficiency was increased from 3.3%–7% before and after packing ZrO2 pellets into the DBD reactor. It was concluded that the packing ZrO2 simultaneously increases the key values, decomposition rate and energy efficiency, by a factor of two, which makes it very promising. The improved decomposition rate and energy efficiency can be attributed mainly to the stronger electric field and electron energy and the lower reaction temperature. Full article
(This article belongs to the Special Issue Plasma Catalysis)
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18 pages, 5364 KiB  
Article
Mode Transition of Filaments in Packed-Bed Dielectric Barrier Discharges
by Mingxiang Gao, Ya Zhang, Hongyu Wang, Bin Guo, Quanzhi Zhang and Annemie Bogaerts
Catalysts 2018, 8(6), 248; https://doi.org/10.3390/catal8060248 - 15 Jun 2018
Cited by 25 | Viewed by 4912
Abstract
We investigated the mode transition from volume to surface discharge in a packed bed dielectric barrier discharge reactor by a two-dimensional particle-in-cell/Monte Carlo collision method. The calculations are performed at atmospheric pressure for various driving voltages and for gas mixtures with different N [...] Read more.
We investigated the mode transition from volume to surface discharge in a packed bed dielectric barrier discharge reactor by a two-dimensional particle-in-cell/Monte Carlo collision method. The calculations are performed at atmospheric pressure for various driving voltages and for gas mixtures with different N2 and O2 compositions. Our results reveal that both a change of the driving voltage and gas mixture can induce mode transition. Upon increasing voltage, a mode transition from hybrid (volume+surface) discharge to pure surface discharge occurs, because the charged species can escape much more easily to the beads and charge the bead surface due to the strong electric field at high driving voltage. This significant surface charging will further enhance the tangential component of the electric field along the dielectric bead surface, yielding surface ionization waves (SIWs). The SIWs will give rise to a high concentration of reactive species on the surface, and thus possibly enhance the surface activity of the beads, which might be of interest for plasma catalysis. Indeed, electron impact excitation and ionization mainly take place near the bead surface. In addition, the propagation speed of SIWs becomes faster with increasing N2 content in the gas mixture, and slower with increasing O2 content, due to the loss of electrons by attachment to O2 molecules. Indeed, the negative O2 ion density produced by electron impact attachment is much higher than the electron and positive O2+ ion density. The different ionization rates between N2 and O2 gases will create different amounts of electrons and ions on the dielectric bead surface, which might also have effects in plasma catalysis. Full article
(This article belongs to the Special Issue Plasma Catalysis)
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Review

Jump to: Editorial, Research

40 pages, 8134 KiB  
Review
The Use of Zeolites for VOCs Abatement by Combining Non-Thermal Plasma, Adsorption, and/or Catalysis: A Review
by Savita K. P. Veerapandian, Nathalie De Geyter, Jean-Marc Giraudon, Jean-François Lamonier and Rino Morent
Catalysts 2019, 9(1), 98; https://doi.org/10.3390/catal9010098 - 17 Jan 2019
Cited by 121 | Viewed by 16418
Abstract
Non-thermal plasma technique can be easily integrated with catalysis and adsorption for environmental applications such as volatile organic compound (VOC) abatement to overcome the shortcomings of individual techniques. This review attempts to give an overview of the literature about the application of zeolite [...] Read more.
Non-thermal plasma technique can be easily integrated with catalysis and adsorption for environmental applications such as volatile organic compound (VOC) abatement to overcome the shortcomings of individual techniques. This review attempts to give an overview of the literature about the application of zeolite as adsorbent and catalyst in combination with non-thermal plasma for VOC abatement in flue gas. The superior surface properties of zeolites in combination with its excellent catalytic properties obtained by metal loading make it an ideal packing material for adsorption plasma catalytic removal of VOCs. This work highlights the use of zeolites for cyclic adsorption plasma catalysis in order to reduce the energy cost to decompose per VOC molecule and to regenerate zeolites via plasma. Full article
(This article belongs to the Special Issue Plasma Catalysis)
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