Ni-based catalyst over rice husk-derived silica for the CO2 methanation reaction: Effect of Ru addition

Amorphous, high purity and sulfur-free silica was obtained from rice husk, which was used as support in metal catalysts. Ni and Ni-Ru catalysts were synthesized by wet impregnation over SiO 2 . The metallic loading was varied keeping the Ru/Ni ratio equal to 0.1. The solids were characterized by different techniques such as XRD, FT-IR, N 2 adsorption, XRF, HRTEM, EDX, Raman, TPR, H 2 -TPD and XPS. They were evaluated in the CO 2 methanation reaction between 250 and 400 °C. The rice husk-derived silica allowed obtaining Ni-based catalysts more suitable for CO 2 methanation than commercial fumed silica. The incorporation of low amounts of Ru into Ni-based catalysts decreased particle size and improved the reducibility of NiO as well as the H 2 adsorption capacity. The catalysts were active and stable. The Ni5Ru solid resulted the most promising catalyst for the CO 2 methanation reaction by achieving the highest methane production rate with the lowest metal loading. • Amorphous, high purity and sulfur-free silica was obtained from rice husk. • Ni and Ni-Ru catalysts were synthesized by wet impregnation over SiO 2 . • The incorporation of low amounts of Ru into Ni catalysts decreased particle size. • Ru addition improved the reducibility of NiO as well as the H 2 adsorption capacity. • The Ni5Ru solid resulted the most promising catalyst for the CO 2 methanation reaction.