Abstract: The low temperature plasma i.e. non-thermal plasma (NTP) produced by dielectric barrier discharge was employed to decompose NO_x in C₃H₆/NO/N₂ mixture. How to make this process higher conversion efficiency with lower energy cost is a topic of the present study. In order to study the effect of hydrocarbon on NO conversion in diesel exhaust, in experimental study C₃H₆/NO/N₂ mixture was treated by NTP and an optical emission spectroscopy diagnosis technology adopted to obtain the information about radicals and excimer in the discharge space produced by NTP. The results indicate that with increase of discharge power, NO conversion efficiency increases sharply first and then slows down to a constant value, and NO₂ concentration gradually decreases while N₂O concentration grows up first and then goes down. NO in the mixture is mainly reduced to N₂. At the same discharge power, with increase of C₃H₆ initial concentration NO_x conversion efficiency and N₂O concentration increases while NO₂ concentration decreases. The addition of C₃H₆ can make the spectral intensity of NO-γ band and N₂ second positive band decreases, while do CN radical to stimulate the transition spectral line, which can affect NO conversion mechanism, and so the formation of yellow polymer.

Key words: non-thermal plasma, emission spectroscopy, hydrocarbon, NO conversion, radical, chemical reaction

摘要： 利用介质阻挡放电产生低温等离子体转化C₃H₆/NO/N₂气氛中NO，结合发射光谱诊断法研究了碳氢化合物C₃H₆对NO转化的影响。研究结果表明，随着放电功率的升高，NO转化率先升高后逐渐趋于平缓，NO₂浓度持续降低，N₂O浓度呈先升高后降低趋势，NO主要被还原为N₂；相同放电功率下，随着C₃H₆初始浓度升高，NO_x转化率和N₂O浓度升高、NO₂浓度降低；添加C₃H₆会降低N₂第二正带系和NO-γ带的发射光谱强度，产生CN自由基的激发跃迁谱线，影响NO的化学反应机制，同时生成了棕黄色的聚合物。

关键词: 低温等离子体, 发射光谱, 碳氢化合物, NO转化, 自由基, 化学反应