The past decade has seen rapid advances in catalyst development for CO2 methanation. Both noble (e.g., Ru, Rh and Pd) and non-noble (e.g., Ni, Co and Fe) metal catalysts have been extensively studied . Among these catalysts, Ru-based catalysts are the most effective, especially at low metal loading and low reaction temperatures. Their activity and selectivity in methanation are typically governed by the nanoscale properties, such as Ru nanoparticle size and shape , nature of the support , structural/electronic metal-support interactions and promoter/doping effects . With respect to the nature of the support, a considerable amount of literature has focused on reducible oxides, including TiO2 and CeO2, because the presence of oxygen vacancies and the propensity of charge transfer from reducible support are thought to stabilize small Ru nanoparticles . Far less attention has been paid to inert oxides, SiO2 in particular. Silica, a typically high specific surface area support with large pore volume, is particularly suited to disperse metal nanoparticles. SiO2 also has good thermal stability, which can help steer clear of support sintering or support overgrowth on Ru sites during catalyst preparation and methanation reaction. Nevertheless, silicasupported methanation catalysts are generally shown to be only moderately active, possibly due to the absence of oxygen vacancies and basicity . However, strategies have emerged to improve methanation activity. For instance, ionic liquids can be employed to stabilize the dispersion of Ru nanoparticles on SiO2 . 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]BF4) can form a protective layer that prevents the agglomeration and oxidation of Ru nanoparticles while also providing weak and medium basic sites. Highly dispersed small Ru nanoparticles and appropriate basic property thus result in high CO2 methanation activity at low temperature. Alternatively, the presence of passivating groups (-OSi(Me)2R with R = Me or Bu) at the surface of SiO2 supported Ru nanoparticles was shown to promote methanation activity by lowering CO adsorption affinity on Ru nanoparticles .