Entanglement of CH₄ and CO₂ Chemistries in Plasma‐Assisted Dry Reforming of Methane

Plasma‐assisted dry reforming of methane converts methane (CH 4 ) and carbon dioxide (CO 2 ) into valuable chemicals. To gain further chemical kinetic insights into this process, laboratory‐scale experiments is combined using isotopically labeled 13 CO 2 with detailed chemical modeling. In the experiments, an atmospheric‐pressure coaxial dielectric barrier discharge plasma reactor attached to a molecular‐beam mass spectrometer is used to detect reaction products from a feed mixture containing equal amounts of CH 4 and CO 2 . The experiments confirm that the formation of the observed hydrocarbons is clearly related to the CH 4 chemistry and that the detected double‐oxygenated C 2 H 4 O 2 , C 3 H 6 O 2 , and C 4 H 8 O 2 species can partially be traced back to the CO 2 chemistry. To provide further insights, the chemistry mechanism from the earlier work ( Proc. Combust. Inst., 2024, 40, 105404) is expanded to include the formation chemistry of these double‐oxygenated products. The updated mechanism predicts the formation of both acids and esters, for example, acetic acid (CH 3 COOH) and methyl formate [HC(=O)OCH 3 ] for the C 2 H 4 O 2 species. According to the reaction path analysis, the products are formed through the COOH radical that itself stems from the CO+OH reaction, with the CO being partially formed from plasma‐initiated CO 2 dissociation.