Investigating the roles of plasma active species in plasma chemical reaction process can improve understanding of the mechanism of volatile organic compounds degradation by plasma. In this work, different experimental processes were designed to distinguish the contributions of various active species of plasma in the decomposition of toluene by a dielectric barrier discharge plasma with or without the CoMnOx/TiO2 catalyst. The removal efficiency of toluene, selectivity of COx (CO2 and CO), and byproducts were detected. The results showed that within the post-plasma zone, toluene could be oxidized to organic intermediates but not completely oxidized to COx by the long-lived active species of O2 plasma; furthermore, O3 alone could not degrade toluene in the gas phase, and the active species generated by N2 discharge could not degrade toluene. In the plasma area, toluene could be decomposed by both the short- and long-lived active species, and could be oxidized to COx by the short-lived active species. The introduction of CoMnOx/TiO2 catalyst, whether within or after the plasma zone, could efficiently decompose O3 and greatly improve the utilization of the active species, thus increasing the removal efficiency of toluene and the selectivity of COx.

中文翻译：

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各种等离子体活性物质在非热等离子体和等离子体催化降解甲苯中的作用

研究等离子体活性物质在等离子体化学反应过程中的作用可以提高对等离子体降解挥发性有机化合物机制的理解。在这项工作中，设计了不同的实验过程，以区分各种活性等离子体在使用或不使用 CoMnOx/TiO2 催化剂的介质阻挡放电等离子体分解甲苯中的贡献。检测甲苯的去除效率、COx（CO2 和CO）的选择性和副产物。结果表明，在后等离子体区，O2等离子体的长寿命活性物种可以将甲苯氧化为有机中间体，但不能完全氧化为COx；此外，O3单独不能降解气相中的甲苯，N2放电产生的活性物种不能降解甲苯。在等离子体区域，甲苯可以被短寿命和长寿命的活性物质分解，并且可以被短寿命的活性物质氧化成 COx。CoMnOx/TiO2催化剂的引入，无论是在等离子体区内还是等离子体区之后，都可以有效地分解O3，大大提高活性物种的利用率，从而提高甲苯的去除效率和COx的选择性。