(532bs) First-Principles Calculations to Predict the Plasma Effects for Non-Oxidative Coupling of Methane on the Transition Metal-Doped TiO2

The catalytic conversion of methane into C₂ species is considered to be a solution to serious climate problems and limited petroleum or coal reserves in oil-free olefin production. However, developing methane-reforming technology remains challenging due to the strong C-H bond and high activation energy. In this regard, non-thermal plasma can be a possible solution for resolving the long-standing issue of methane direct conversion. It has the potential to decrease the activation energy of the rate-determining step, thereby breaking the scaling connection. Thus, even when the same catalyst is utilized, plasma is likely to boost catalytic activity or lower the operating temperature. In this study, we conducted a theoretical analysis to better understand the plasma associated methane conversion activity on 3d transition metal-doped TiO₂. It has been reported that the TiO₂catalyst is stable when the methane conversion reaction occurs in a plasma environment. First of all, we determined the reaction and activation energies for each stage of the reaction. We confirmed that the reaction and activation energy of each elementary step have a direct or inverse linearity with the oxygen vacancy formation energy. Second, we calculated the turnover frequency (TOF) utilizing plasma-implemented microkinetic modeling. In comparison to plasma-free conditions, the activity with plasma was greater than that of a reaction without plasma influence. Additionally, we determined the optimal dopants for TiO₂ catalysts. These findings will be helpful to the development of potentially advantageous TiO₂-based catalysts for the plasma-assisted methane coupling process.