A comparative study on the kinetics of carbon dioxide methanation over bimetallic and monometallic catalysts

In this paper, Ni/Al and La-Ni/Al catalysts were prepared with a co-impregnation method and then employed in a carbon dioxide methanation reaction. The catalytic results showed that the catalyst with (10wt. %) lanthanum and (20wt.%) nickel had the highest activity at low temperatures in CO2 methanation, and the La-Ni/Al catalysts changed the reaction path by lowering its activation energy and consequently increased the rate of reaction. Moreover, the kinetic behavior of the bimetallic and monometallic catalysts in the CO2 methanation reaction was investigated as functions of partial pressures of H2 and CO2 in order to determine the changes in the parameters of power-law type rate expression resulting from the addition second metal to the catalyst and the change in the La/Ni ratio. The reaction orders (α and β) and the rate constant (k) were estimated by non-linear regression analysis that minimized the sum of the squared differences of calculated and experimental CO2 methanation rates. The results showed that the reaction rate is more sensitive to H2 partial pressure than CO2 partial pressure.