Notably, Ti atoms are highly dispersed in the SiO2 matrix even if a minor fraction of oligomeric or small nanodomains of Ti species are also formed at high loadings. TiO2 nanocrystals are not yet formed at this stage even after calcination at 550°C. This work has shown that Ti species play a marked beneficial role in stabilizing RuO2 nanoparticles, impeding their crystal growth during the calcination. Especially in Ru/12%Ti-SiO2 and Ru/16%Ti-SiO2 catalysts, the impregnation of RuO2 nanoparticles and subsequent calcination induce the crystallization of small anatase TiO2 domains, in turn forming interfacial contact between RuO2 and TiO2. This turned out to strongly affect the methanation activity obtained after in-situ pre-reduction. As a general trend, CO2 conversion rate increases with an increase in Ru dispersion. At 300 C, Rumass-normalized CO2 conversion rate of Ru/12%Ti-SiO2 is 2.3 times higher than that of Ru/SiO2. Our finding that the apparent activation energy is modified upon Ti promotion further suggests that the nature of the active sites is modified by Ti loading. As evidenced by in-situ DRIFTS experiments, CO2 dissociation over Ru/12%Ti-SiO2 catalyst occurs at a temperature as low as 100 C. Importantly, Ti promoter existing in the form of anatase TiO2 crystallites promotes the adsorption of CO at the metal-support interface, which could be held responsible for the catalytic activity improvement. The present study has helped clarify the promotional effect of Ti on Ru/SiO2 catalysts for CO2 methanation. More broadly, the versatile and highly potent synthesis method presented herein offers the possibility to explore other metal promoters in CO2 methanation.