Evaluating the Performance of a Ni Catalyst Supported on La₂O₃-MgAl₂O₄ for Dry Reforming of Methane in a Packed Bed Dielectric Barrier Discharge Plasma Reactor

Ni/La₂O₃-MgAl₂O₄ has been investigated for dry reforming of methane (DRM) in a cold plasma dielectric barrier discharge (DBD) fixed-bed reactor. Ni/La₂O₃-MgAl₂O₄ was prepared according to the modified coprecipitation assisted hydrothermal method. The samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectroscopy (EDX) mapping, N₂ adsorption-desorption, H₂-TPR, CO₂-TPD, the coaxial dielectric probe method, and thermogravimetric analysis (TGA). Incorporating web structured-like La₂O₃ into MgAl₂O₄ changes the irregular structure of MgAl₂O₄ into flakes. The addition of La₂O₃ as a cosupport enhances the Ni-support interaction and basicity of Ni/La₂O₃-MgAl₂O₄. Ni/La₂O₃-MgAl₂O₄ significantly improves the conversion of CH₄ and CO₂ to 86% and 84.5%, respectively. The selectivity for H₂ and CO is 50% and 49.5%, respectively. The syngas ratio (H₂/CO) significantly improves from 0.86 to 1.01, while the overall energy efficiency is 26% higher than that of plasma only DRM. The enhanced DRM activity is ascribed to the higher basicity and better dielectric properties of the catalyst. The formation of intermediate carbonate (La₂O₂CO₃) inhibited carbon deposition as evident by TGA and EDX mapping. Furthermore, the catalyst is also successfully regenerated, and stable DRM performance is maintained during cyclic runs. The stability of the reported plasma-catalyst system is encouraging for further investigation to make DBD plasma DRM economically viable.