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, N-2 adsorption-desorption, H-2-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 H-2 and CO2 is 50% and 49.5%, respectively. The syngas ratio (H-2/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 DRIVI 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.