A temperature-controlled and pressure-controlled coaxial dielectric barrier discharge (DBD) reactor was developed to decouple the thermal and kinetic effects of radio frequency (RF) discharge on methane conversion

and further to compare the kinetic behaviors of the mechanistically similar reactions of methane conversion with O

2

and CO

2

additives. A kinetic mechanism for RF plasma assisted methane conversion was assembled. The formation of products in the RF plasma reactor was measured with Gas Chromatography (GC-TCD) and the data were used to validate the kinetic model. The experimental and computational results showed the different kinetic roles of carbon dioxide and oxygen additives in methane conversion

due to the different dissociation and ionization energy of the two additive gases

as well as the thus produced electron energy distribution function (EEDF). Fuel oxidation by plasma generated O

O(

1

D)

O

2

(a

1

Δ

g

)

O

2

(b

1

Σ

g

+

) and O

+

in partial oxidation of methane was observed essential for methane consumption

which resulted in

an increase in methane conversion rate

compared to pure methane pyrolysis and dry reforming of methane with CO

2

additive. It was also found that dry reforming of methane with CO

2

was by far the easier to produce the syngas as well as C

2

hydrocarbon species

due to the weak oxidation ability of CO

2

and also the significant deposition of the electron energy on CH

4

dissociation in a dry reforming discharge mixture. This kinetic study produced comparative data to demonstrate the contribution of CO

2

/O

2

additive in non-equilibrium plasma assisted methane conversion.