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

• Non-thermal plasma (NTP)-assisted CO 2 methanation over promoted Ni/ CeZrO x catalyst. • Basic sites, Ni dispersion and oxygen vacancies are key parameters to substantially increase catalytic activity. • A decrease of catalyst’s dielectric constant is beneficial in terms of power consumption for NTP-assisted CO 2 methanation. • Both physicochemical and electrical properties of the catalyst are essential for high efficiency of plasma catalytic process. 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 CO 2 methanation. The influence of physicochemical properties was examined by X-Ray Diffraction, N 2 adsorption/desorption, H 2 -TPR, CO 2 -TPD, TPD-MS and FTIR spectroscopy. Moreover, the measurement of the dielectric constant of each catalyst was also performed. The promotion of Ni/CeZrO x with 4 wt% Gd significantly increases the energy efficiency. Furthermore, NiCZ-Gd resulted in the highest activity with 85 % conversion of CO 2 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 CO 2 methanation.