Mass spectrometric investigation of the ionic species in a dielectric barrier discharge operating in helium-water vapour mixtures
Mass spectrometric investigation of the ionic species in a dielectric barrier discharge operating in helium-water vapour mixtures
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DOI：
10.1088/0022-3727/48/8/085202
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发表时间：
2015-03-04
影响因子：
3.4
通讯作者：
Bradley, J. W.
中科院分区：
文献类型：
--
作者：
Abd-Allah, Z.;Sawtell, D. A. G.;Bradley, J. W.
使用先进的质谱分析法，可以识别通电电极上具有单个电介质的大气压平行板电介质阻挡放电 (DBD) 中存在的离子物质的化学性质。使用 10 kHz 的激励频率和 1.2 kV 的外加电压，在具有可控水蒸气浓度的氦气中驱动放电。负离子和正离子均被识别，并且它们的相对强度随放电中的水浓度、电极间距、气体停留时间和标称施加功率的变化而确定。最丰富的负离子是 OH-(H2O)(n) 家族，而正离子主要是 H+(H2O)(n) 形式的离子，两种情况下 n 都高达 9。负离子和正离子对操作参数变化的响应方式类似，具体响应取决于离子质量。增加电极间间距和放电中的水浓度导致大质量离子水簇的强度增加。然而，增加物质在等离子体区域的停留时间和增加施加的功率会导致大水簇分裂，产生更小的离子。
Using advanced mass spectrometry the chemistry of ionic species present in an atmospheric-pressure parallel plate dielectric barrier discharge (DBD) with a single dielectric on the powered electrode have been identified. The discharge was driven in helium with controllable concentrations of water vapour using an excitation frequency of 10 kHz and an applied voltage of 1.2 kV. Both negative and positive ions were identified and their relative intensity determined with variation of water concentration in the discharge, inter-electrode spacing, gas residence time and nominal applied power. The most abundant negative ions were of the family OH-(H2O)(n), while the positive ions were dominated by those of the form H+(H2O)(n), with n up to 9 in both cases. Negative and positive ions responded in a similar way to changes in the operating parameters, with the particular response depending on the ion mass. Increasing the inter-electrode spacing and the water concentration in the discharge led to an increase in the intensity of large mass ionic water clusters. However, increasing the residence time of the species in the plasma region and increasing the applied power resulted in fragmentation of large water clusters to produce smaller ions.