Effect of Ca, Ce or K oxide addition on the activity of Ni/SiO2 catalysts for the methane decomposition reaction

To increase the activity and stability of Ni/SiO2 catalysts, a series of Ni–Ca, Ni–K and Ni–Ce promoted catalysts were prepared by successive impregnations. The textural properties, reducibility and catalytic performance in the methane decomposition reaction were investigated. The catalyst containing 30 wt.% Ni and 30 wt.% cerium oxide greatly increased the conversion of methane (90% of equilibrium value) and improved the stability, whereas the Ni–K and Ni–Ca were less active and stable than the Ni/SiO2 catalyst. The results suggest that Ce addition prevents the sintering of nickel particles during reduction process maintaining a random distribution between the silica and cerium oxide improving the distribution and migration of deposited carbon.