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Zhang, Y.-R.; Neyts, E.C.; Bogaerts, A. | ||||
| Title | Influence of the Material Dielectric Constant on Plasma Generation inside Catalyst Pores | Type | A1 Journal article | ||
| Year | 2016 | Publication | The journal of physical chemistry: C : nanomaterials and interfaces | Abbreviated Journal | J Phys Chem C |
| Volume | 120 | Issue | 120 | Pages | 25923-25934 |
| Keywords | A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) | ||||
| Abstract | Plasma catalysis is gaining increasing interest for various environmental applications, but the crucial question is whether plasma can be created inside catalyst pores and under which conditions. In practice, various catalytic support materials are used, with various dielectric constants. We investigate here the influence of the dielectric constant on the plasma properties inside catalyst pores and in the sheath in front of the pores, for various pore sizes. The calculations are performed by a two-dimensional fluid model for an atmospheric pressure dielectric barrier discharge in helium. The electron impact ionization rate, electron temperature, electron and ion density, as well as the potential distribution and surface charge density, are analyzed for a better understanding of the discharge behavior inside catalyst pores. The results indicate that, in a 100 μm pore, the electron impact ionization in the pore, which is characteristic for the plasma generation inside the pore, is greatly enhanced for dielectric constants below 300. Smaller pore sizes only yield enhanced ionization for smaller dielectric constants, i.e., up to εr = 200, 150, and 50 for pore sizes of 50, 30, and 10 μm. Thus, the most common catalyst supports, i.e., Al2O3 and SiO2, which have dielectric constants around εr = 8−11 and 4.2, respectively, should allow more easily that microdischarges can be formed inside catalyst pores, even for smaller pore sizes. On the other hand, ferroelectric materials with dielectric constants above 300 never seem to yield plasma enhancement inside catalyst pores, not even for 100 μm pore sizes. Furthermore, it is clear that the dielectric constant of the material has a large effect on the extent of plasma enhancement inside the catalyst pores, especially in the range between εr = 4 and εr = 200. The obtained results are explained in detail based on the surface charge density at the pore walls, and the potential distribution and electron temperature inside and above the pores. The results obtained with this model are important for plasma catalysis, as the production plasma species in catalyst pores might affect the catalyst properties, and thus improve the applications of plasma catalysis. |
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| Language | Wos | 000388429100029 | Publication Date | 2016-11-17 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 1932-7447 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 4.536 | Times cited | 34 | Open Access | |
| Notes | This work was supported by the Fund for Scientific Research Flanders (FWO) (Grant G.0217.14N), the National Natural Science Foundation of China (Grant 11405019), and the China Postdoctoral Science Foundation (Grant 2015T80244). This work was carried out in part using the Turing HPC infrastructure at the CalcUA core facility of the Universiteit Antwerpen, a division of the Flemish Supercomputer Center VSC, funded by the Hercules Foundation, the Flemish Government (department EWI), and the University of Antwerp. | Approved | Most recent IF: 4.536 | ||
| Call Number | PLASMANT @ plasmant @ c:irua:138602 | Serial | 4319 | ||
| Permanent link to this record | |||||
| Author |
Zhang, Y.-R.; Neyts, E.C.; Bogaerts, A. | ||||
| Title | Enhancement of plasma generation in catalyst pores with different shapes | Type | A1 Journal article | ||
| Year | 2018 | Publication | Plasma sources science and technology | Abbreviated Journal | Plasma Sources Sci T |
| Volume | 27 | Issue | 5 | Pages | 055008 |
| Keywords | A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) | ||||
| Abstract | Plasma generation inside catalyst pores is of utmost importance for plasma catalysis, as the existence of plasma species inside the pores affects the active surface area of the catalyst available to the plasma species for catalytic reactions. In this paper, the electric field enhancement, and thus the plasma production inside catalyst pores with different pore shapes is studied with a two-dimensional fluid model. The results indicate that the electric field will be significantly enhanced near tip-like structures. In a conical pore with small opening, the strongest electric field appears at the opening and bottom corners of the pore, giving rise to a prominent ionization rate throughout the pore. For a cylindrical pore, the electric field is only enhanced at the bottom corners of the pore, with lower absolute value, and thus the ionization rate inside the pore is only slightly enhanced. Finally, in a conical pore with large opening, the electric field is characterized by a maximum at the bottom of the pore, yielding a similar behavior for the ionization rate. These results demonstrate that the shape of the pore has a significantly influence on the electric field enhancement, and thus modifies the plasma properties. | ||||
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| Publisher | Place of Publication | Editor | |||
| Language | Wos | 000432351700002 | Publication Date | 2018-05-15 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 1361-6595 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.302 | Times cited | 11 | Open Access | OpenAccess |
| Notes | This work was supported by the Fund for Scientific Research Flanders (FWO) (Grant No. G.0217.14N) and the Fundamental Research Funds for the Central Universities (Grant No. DUT17LK52). | Approved | Most recent IF: 3.302 | ||
| Call Number | PLASMANT @ plasmant @c:irua:151546 | Serial | 4998 | ||
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| Author |
Zhang, Y.-R.; Van Laer, K.; Neyts, E.C.; Bogaerts, A. | ||||
| Title | Can plasma be formed in catalyst pores? A modeling investigation | Type | A1 Journal article | ||
| Year | 2016 | Publication | Applied catalysis : B : environmental | Abbreviated Journal | Appl Catal B-Environ |
| Volume | 185 | Issue | 185 | Pages | 56-67 |
| Keywords | A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) | ||||
| Abstract | tWe investigate microdischarge formation inside catalyst pores by a two-dimensional fluid model forvarious pore sizes in the m-range and for various applied voltages. Indeed, this is a poorly understoodphenomenon in plasma catalysis. The calculations are performed for a dielectric barrier discharge inhelium, at atmospheric pressure. The electron and ion densities, electron temperature, electric field andpotential, as well as the electron impact ionization and excitation rate and the densities of excited plasmaspecies, are examined for a better understanding of the characteristics of the plasma inside a pore. Theresults indicate that the pore size and the applied voltage are critical parameters for the formation of amicrodischarge inside a pore. At an applied voltage of 20 kV, our calculations reveal that the ionizationmainly takes place inside the pore, and the electron density shows a significant increase near and inthe pore for pore sizes larger than 200m, whereas the effect of the pore on the total ion density isevident even for 10m pores. When the pore size is fixed at 30m, the presence of the pore has nosignificant influence on the plasma properties at an applied voltage of 2 kV. Upon increasing the voltage,the ionization process is enhanced due to the strong electric field and high electron temperature, andthe ion density shows a remarkable increase near and in the pore for voltages above 10 kV. These resultsindicate that the plasma species can be formed inside pores of structured catalysts (in the m range),and they may interact with the catalyst surface, and affect the plasma catalytic process. | ||||
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| Publisher | Place of Publication | Editor | |||
| Language | Wos | 000369452000006 | Publication Date | 2015-12-11 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 0926-3373 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 9.446 | Times cited | 75 | Open Access | |
| Notes | This work was supported by the Fund for Scientific ResearchFlanders (FWO) (Grant no. G.0217.14N), the National Natural Sci-ence Foundation of China (Grant no. 11405019), and the ChinaPostdoctoral Science Foundation (Grant no. 2015T80244). Theauthors are very grateful to V. Meynen for the useful discussions oncatalysts. This work was carried out in part using the Turing HPCinfrastructure at the CalcUA core facility of the Universiteit Antwer-pen, a division of the Flemish Supercomputer Center VSC, fundedby the Hercules Foundation, the Flemish Government (departmentEWI) and the University of Antwerp. | Approved | Most recent IF: 9.446 | ||
| Call Number | c:irua:129808 | Serial | 3984 | ||
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