Nonthermal Plasma-Driven Non-Oxidative Coupling of Methane at Room Temperature

In this study, a nonthermal plasma (dielectric barrier discharge (DBD)) system was applied to perform dehydrogenated methane (CH₄) coupling reaction at room temperature without combination with heterogeneous catalysts, aiming for direct conversion into high-value C₂+ hydrocarbons. Also, this reaction is scientifically important that nonthermal plasma is applicable to C-C bond creation. Conventional CH₄ conversion technologies rely on high-temperature thermocatalytic processes, typically involving indirect pathways via syngas production. These approaches suffer from high energy consumption and complex process configurations.

To overcome these challenges, we employed DBD plasma, which generates reactive species through electrical discharge, enabling the activation of CH₄ and facilitating non-oxidative coupling of methane (NOCM) even under room temperature. Unlike conventional NOCM reactions that require high temperatures and energy, DBD approach enables low-temperature conversion by lowering the activation energy through nonthermal processes. In particular, under low-pressure operation, the use of high-frequency DBD enhanced CH₄ conversion and enabled the selective synthesis of valuable higher hydrocarbons.

This work presents a promising low-energy and carbon-neutral strategy for CH₄ utilization, highlighting the potential of nonthermal plasma-assisted direct conversion of CH₄ into higher hydrocarbons at room temperature.