The reducibility of Ru/x%Ti-SiO2 catalysts was investigated using H2-TPR. The shape of H2-TPR profile is similar among all catalysts in Fig. (b). One main peak can be observed and ascribed to the reduction of oxidic Ru species. This reduction peak is centered at around 200 °C for Ru/SiO2 and shifted toward lower temperatures with higher Ti loading up to 12%, followed by a shift toward higher temperature for 16% Ti loading. Enhanced reducibility with increased Ti loading is possibly related to the stabilization of smaller RuO2 nanoparticles by Ti species. Notably, it has been reported that smaller RuO2 nanoparticles have lower activation energy for hydrogen dissociation .