Nonthermal Plasma-Catalytic Dry Reforming of Methane in Parallel-Plate Dielectric Barrier Discharge Reactor Using Mg-Modified Ni Catalysts

Abstract

The conversion of greenhouse gases, particularly CO₂ and CH₄, into syngas via dry reforming of methane (DRM) has effectively mitigated global warming and climate change issues. The research objectives are to enhance the DRM efficiency and reduce coke formation using Ni catalysts supported on Mg-modified Al₂O₃ in parallel plate dielectric barrier discharge. Raising the Ni calcination temperature from (Ni/Mg–Al₂O₃-500) to 700 °C (Ni/Mg–Al₂O₃-700) enhances NiO reduction temperatures, thus diminishing their reducibility. This indicates that Ni/Mg–Al₂O₃-700 exhibits stronger NiO–Al₂O₃ interaction, resulting in increased metal dispersion and decreased crystallite and particle sizes. As the Ni calcination temperature increases from 700 to 800 °C (Ni/Mg–Al₂O₃-800) the intensity of the Ni_0.8Mg_0.11Al₂O₄ spinel structure is enhanced. The increased Ni calcination temperature enhances the metal-support sintering processes and promotes the metal nanoparticle cluster formation, leading to increased particle and crystallite sizes, alongside decreased dispersion of Ni and Mg particles on the catalyst surface. The Ni/Mg–Al₂O₃-700 exhibits lowest NiO reducibility, strongest NiO–Al₂O₃ interaction, highest metal dispersion, highest specific surface area, smallest particle, and crystallite sizes. Consequently, it attains the highest CH₄ and CO₂ conversions, H₂ and CO selectivities, and energy efficiency, as well as the lowest coking rate, carbon deposition, carbon loss, and specific energy consumption.