A surface mechanism for O 3 production with N 2 addition in dielectric barrier discharges
A surface mechanism for O 3 production with N 2 addition in dielectric barrier discharges
复制标题
介质阻挡放电中添加 N 2 产生 O 3 的表面机制
DOI：
10.1088/1361-6595/ace95d
复制
发表时间：
2023
影响因子：
3.8
通讯作者：
Kushner, Mark J.
中科院分区：
文献类型：
--
作者：
Meyer, Mackenzie;Foster, John;Kushner, Mark J.
臭氧（O 3）是一种强氧化剂，常用于水净化。 O 3 通常在电介质阻挡放电 (DBD) 中通过 O 2 的电子碰撞解离，然后发生 O 和 O 2 之间的三体缔合反应而产生。之前对低温等离子体 DBD 中 O 3 形成的研究表明，持续运行后，O 3 浓度可降至接近于零，称为零臭氧现象 (OZP)。尽管功率沉积从O 2 转向N 2 并产生氮氧化物N x O y ，但包含少量(<4％)的N 2 混合物可以抑制这种现象并相对于使用纯O 2 增加O 3 产量。假设OZP 的发生是因为O 3 在与等离子体接触的表面上被破坏。在气体混合物中包含N 2 使得N原子能够占据否则会参与O 3 破坏的表面位点。使用全局等离子体化学模型对产生臭氧的 DBD 中 N 2 的影响进行了计算研究。提出了一般的表面反应机制来解释N 2 混合物导致O 3 产量的增加。其机理包括O 3 在表面的形成和破坏、O和N的吸附和复合、O 2 和N 2 的解吸以及NO x 反应。如果表面没有这些反应，O 3 的密度会随着N 2 混合量的增加而单调降低，这是由于N 2 的功率吸收导致氮氧化物的形成。对于基于N的表面化学，O 3 的浓度最大，为N 2 的百分之几，具体取决于表面上O 3 破坏的概率。表面化学对臭氧产生的影响小于没有表面处理的气体温度的影响。当O 3 的表面破坏概率或表面粗糙度降低时，基于N的表面化学会导致O 3 密度增加。
Ozone, O 3, is a strong oxidizing agent often used for water purification. O 3 is typically produced in dielectric barrier discharges (DBDs) by electron-impact dissociation of O 2, followed by three-body association reactions between O and O 2. Previous studies on O 3 formation in low-temperature plasma DBDs have shown that O 3 concentrations can drop to nearly zero after continued operation, termed the ozone-zero phenomenon (OZP). Including small (< 4%) admixtures of N 2 can suppress this phenomenon and increase the O 3 production relative to using pure O 2 in spite of power deposition being diverted from O 2 to N 2 and the production of nitrogen oxides, N x O y. The OZP is hypothesized to occur because O 3 is destroyed on the surfaces in contact with the plasma. Including N 2 in the gas mixture enables N atoms to occupy surface sites that would otherwise participate in O 3 destruction. The effect of N 2 in ozone-producing DBDs was computationally investigated using a global plasma chemistry model. A general surface reaction mechanism is proposed to explain the increase in O 3 production with N 2 admixtures. The mechanism includes O 3 formation and destruction on the surfaces, adsorption and recombination of O and N, desorption of O 2 and N 2, and NO x reactions. Without these reactions on the surface, the density of O 3 monotonically decreases with increasing N 2 admixture due to power absorption by N 2 leading to the formation of nitrogen oxides. With N-based surface chemistry, the concentrations of O 3 are maximum with a few tenths of percent of N 2 depending on the O 3 destruction 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 O 3 density with N-based surface chemistry occurs when the surface destruction probability of O 3 or the surface roughness was decreased.