Conversion of NO in NO/N2, NO/O2/N21 NO/C2H4/N2 and NO/C2H4/O2/N2 Systems by Dielectric Barrier Discharge Plasmas

An experimental study on the conversion of NO in the NO/N2, NO|O2|N2, NO/C2H4/N2 and NO1C21141021N2 systems has been carried out using dielectric barrier discharge (DBD) plasmas at atmospheric pressure. In the NOIN2 system, NO decomposition to N2 and O2 is the dominating reaction; NO conversion to NO2 is less significant. O2 produced from NO decomposition was detected by an on-line mass spectrometer. With the increase of NO initial concentration, the concentration of 02 produced decreases at 298 K, but slightly increases at 523K. In the NO1021N2 system, NO is mainly oxidized to NO2, but NO conversion becomes very low at 523 K and over 1.6% of 02. In the NOIC2H41N2 system, NO is reduced to N2 with about the same NO conversion as that in the NOIN2 system but without NO2 formation. In the NO1C21141021N2 system, the oxidation of NO to NO2 is dramatically promoted. At 523 K, with the increase of the energy density, NO conversion increases rapidly first, and then almost stabilizes at 93-91% of NO conversion with 61-55% of NO2 selectivity in the energy density range of 317-550.11,-1. It finally decreases gradually at high energy density. A negligible amount of N20 is formed in the above four systems. Of the four systems studied, NO conversion and NO2 selectivity of the NO1C21141021N2 system are the highest, and NO|O2|C2H4|N2 system has the lowest electrical energy consumption per NO molecule converted.