Non-Oxidative Coupling of Methane Driven by Non-Thermal Plasma: Effect of Packing Materials on Micro-Electric Field

Non-oxidative coupling of methane (CH4) by plasma has received particular attention due to the achievement of high methane conversion and product selectivity at a low temperature. In this work, experimental results suggest that the packing materials directly affect the electric field, which in turn determines the plasma discharge and, subsequently, the conversion of CH4 and the products selectivity. High selectivity to ethylene was obtained by BaTiO3 packing, which can be ascribed to the moderate electric field generated with special physiochemical properties. Furthermore, in the cases of packing by ZSM-5, gamma-Al2O3 or SiO2 granules, small size of granules contributed to generate a stronger electric field, which improves CH4 conversion. However, reverse trend has been found in the case of packing by BaTiO3. Finally, the specific indicator of micro-electric field was developed to illustrate the relationship between reaction performance and packing materials.