Decomposition of N2O by Microwave Discharge of N2O/He or N2O/Ar Mixtures

Abstract

The decomposition of N2O into N2, O2 and NO by a microwave discharge of N2O/He or N2O/Ar mixtures was studied at various total pressures. Although discharge could be maintained only in the low total-pressure range of 1–80 Torr in N2O/He mixtures at N2O and He flow rates of 25 and 2000 sccm, respectively, stable microwave discharge could be maintained in the wide total-pressure range of 1–760 Torr in N2O/Ar mixtures at N2O and Ar flow rates of 25 and 1000 sccm, respectively, at a microwave power of 200 W. The decomposition efficiency of N2O and the branching ratios of products in N2O/Ar mixtures at 760 Torr were measured as a function of the microwave power or the N2O flow ratio at a relatively high N2O concentration range of 9900–47600 ppm. The decomposition mechanism of N2O in the He and Ar discharges is discussed on the basis of mass spectrometric and optical emission spectroscopic data.