The low temperature plasma i.e. non-thermal plasma (NTP) produced by dielectric barrier discharge was employed to decompose NOx 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 NOx 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.