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Title: A surface mechanism for O 3 production with N 2 addition in dielectric barrier discharges
Abstract Ozone, O3, is a strong oxidizing agent often used for water purification. O3is typically produced in dielectric barrier discharges (DBDs) by electron-impact dissociation of O2, followed by three-body association reactions between O and O2. Previous studies on O3formation in low-temperature plasma DBDs have shown that O3concentrations can drop to nearly zero after continued operation, termed the ozone-zero phenomenon (OZP). Including small (<4%) admixtures of N2can suppress this phenomenon and increase the O3production relative to using pure O2in spite of power deposition being diverted from O2to N2and the production of nitrogen oxides, NxOy. The OZP is hypothesized to occur because O3is destroyed on the surfaces in contact with the plasma. Including N2in the gas mixture enables N atoms to occupy surface sites that would otherwise participate in O3destruction. The effect of N2in ozone-producing DBDs was computationally investigated using a global plasma chemistry model. A general surface reaction mechanism is proposed to explain the increase in O3production with N2admixtures. The mechanism includes O3formation and destruction on the surfaces, adsorption and recombination of O and N, desorption of O2and N2, and NOxreactions. Without these reactions on the surface, the density of O3monotonically decreases with increasing N2admixture due to power absorption by N2leading to the formation of nitrogen oxides. With N-based surface chemistry, the concentrations of O3are maximum with a few tenths of percent of N2depending on the O3destruction probability on the surface. The consequences of the surface chemistry on ozone production are less than the effect of gas temperature without surface processes. An increase in the O3density with N-based surface chemistry occurs when the surface destruction probability of O3or the surface roughness was decreased.  more » « less
Award ID(s):
2032604
PAR ID:
10438738
Author(s) / Creator(s):
; ;
Publisher / Repository:
IOP Publishing
Date Published:
Journal Name:
Plasma Sources Science and Technology
Volume:
32
Issue:
8
ISSN:
0963-0252
Page Range / eLocation ID:
Article No. 085001
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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