Kinetic modeling of non-thermal plasma chemistry is conducted to investigate hydrocarbon (CH4, C2H4, C3H6, and C3H8) effects on the promotion of NO–NO2 conversion. A reduced plasma chemistry model, in which radical reactions are selectively involved, is validated with experimental data. The higher reactivity of hydrocarbon additive with O radicals, which produces initial radicals, is requisite to initiate hydrocarbon decomposition, thus providing NO–NO2 conversion. Initial radicals by plasma discharge induce continual hydrocarbon decomposition and this self-preserved reaction mechanism greatly contributes to the promotion of energy efficient NO–NO2 conversion. Increase in the conversion extent by ethylene and propylene additives is substantial because of their stronger affinity with O radical. The primary routes of NO–NO2 conversion process differed by hydrocarbon additives are presented and discussed with the assistance of sensitivity analysis.
