Tailoring physicochemical and electrical properties of Ni/CeZrOx doped catalysts for high efficiency of plasma catalytic CO2 methanation

Promoters covering alkaline earth metals, lanthanides, transition and some of the typical rare earth metals, were added to Ni/CeZrOx based catalysts and examined in non-thermal plasma (NTP)-assisted CO2 methanation. The influence of physicochemical properties was examined by X-Ray Diffraction, N2 adsorption/desorption, H2-TPR, CO2-TPD, TPD-MS and FTIR spectroscopy. Moreover, the measurement of the dielectric constant of each catalyst was also performed. The promotion of Ni/CeZrOx with 4 wt% Gd significantly increases the energy efficiency. Furthermore, NiCZ-Gd resulted in the highest activity with 85 % conversion of CO2 fully converted to methane at 7 W. The enhancement of energy efficiency was attributed to electrical and physicochemical properties in particular: a low dielectric constant, a high metal dispersion, a high percentage of medium basic sites and finally an adequate promoter's cation radii. This study allowed to set up a new methodology to select the most appropriate catalysts in terms of energy efficiency for plasma catalytic CO2 methanation.