Plasma Chemistry of Non‐Oxidative Methane Coupling: Refinement of Theoretically Consistent Reaction Rate Coefficients by DFT Calculations for Improved Kinetic Modelling

ABSTRACT Predictive accuracy of kinetic modelling for plasma‐assisted nonoxidative CH 4 coupling largely depends on the involved rate coefficient uncertainties. Here, we perform density functional theory (DFT) calculations to derive consistent rate coefficients for reactions involving CH x and C 2 H y species. We investigate 34 reactions, including 17 newly‐reported ones and 17 previously reported reactions, of which our recommended values deviate by 1–2 orders of magnitude from the literature. Incorporating these rate coefficients into a DBD plasma kinetic model yields better alignment with experimental data. Specifically, we obtain average improvements of 9%, 23%, and 13% in the model‐predicted C 2 H 6 , C 2 H 4 , and C 2 H 2 selectivities, respectively, compared to a previously established chemistry set. Further kinetic analysis identifies key pathways determining CH 4 conversion and C 2 selectivity.