Plasma-Catalytic Pathways for C1 Activation and Conversion to Value-Added Fuels and Chemicals

The advancement of effective and selective methane (CH4) conversion processes into fuels and chemicals is critical due to the increasing availability of conventional and unconventional methane-rich gas resources (e.g., shale gas, methane hydrate, coalbed methane). These resources are often located in remote areas, far from markets, posing challenges for their utilization. Industrial methane conversion predominantly relies on indirect processes such as steam reforming, while direct one-step conversion remains limited due to the chemical inertness of C-H bonds in CH4. Overcoming this activation barrier conventionally requires high temperatures and substantial energy input, often leading to catalyst deactivation due to carbon deposition.

This dissertation explores the potential of nonthermal plasmas coupled with catalysis as an alternative approach for methane valorization. The first part of this work focuses on the low-temperature plasma-catalytic conversion of methane to aromatic hydrocarbons (benzene, toluene, and xylene) over H-ZSM-5 and Mo/H-ZSM-5 catalysts.We further investigate the dynamic nature of Mo catalytic centers under plasma stimulation, particularly their transformation into carbide phases under methane plasma conditions. In the final section, we explore plasma-driven carbon-nitrogen coupling reactions for the selective synthesis of acetonitrile, demonstrating that gallium nitride catalysts can act as a nitrogen reservoir, interacting with plasma-activated methane species to promote C-N bond formation.

Overall, this work highlights the potential of plasma-catalytic processes for methane activation and conversion, offering new pathways for low-temperature hydrocarbon synthesis while addressing the challenges of conventional catalytic approaches.