教授 博士生导师 硕士生导师
性别: 女
毕业院校: 大连理工大学
学位: 博士
所在单位: 物理学院
学科: 等离子体物理
办公地点: 大连理工大学 科技园大厦C座 519
电子邮箱: yrzhang@dlut.edu.cn
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论文类型: 期刊论文
发表时间: 2021-01-30
发表刊物: JOURNAL OF PHYSICAL CHEMISTRY C
卷号: 120
期号: 45
页面范围: 25923-25934
ISSN号: 1932-7447
摘要: 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 mu m 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 epsilon(r) = 200, 150, and 50 for pore sizes of 50, 30, and 10 mu m. Thus, the most common catalyst supports, i.e., Al2O3 and SiO2, which have dielectric constants around epsilon(r) = 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,mu m 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 epsilon(r) = 4 and epsilon(r) = 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 of plasma species in catalyst pores might affect the catalyst properties, and thus improve the applications of plasma catalysis.