Effects of ambient gas on cold atmospheric plasma discharge in the decomposition of trifluoromethane

The effect of dilution gases (He, Ar and N 2 ) on plasma discharge in the decomposition of trifluoromethane (CHF 3 ) was investigated in dielectric barrier discharge at atmospheric pressure. A comparison among these dilution gases was performed in terms of active power, apparent power, power factor, impedance, and power efficiency for the decomposition of CHF 3 . He dilution showed the most homogeneous and stable discharge among the dilution gases. However, Ar dilution ignited the generation of streamers in the plasma discharge, resulting in a relatively superior power efficiency in CHF 3 decomposition. In addition, due to the plasma reactions between O 2 and N 2 , N 2 as a dilution gas had a disadvantaging tendency to form nitric oxide compounds (harmful compounds). Complete decomposition of CHF 3 could be performed under the following conditions; Ar dilution, active power ≥ 40 W, a CHF 3 fraction of 0.2% and a total flow rate of 1000 ml min −1 . N 2 < He < Ar: the order of energy efficiency for CHF 3 decomposition among these gas discharges.