A granulated material comprising a mixed silicon-titanium oxide powder, wherein a proportion of TiO2 is from 70 to 98 wt %, a proportion of SiO2 is from 2 to 30 wt %, and a sum of TiO2 and SiO2 is at least 98% by weight, and wherein: at room temperature, the TiO2 proportion comprises rutile and more than 50% of anatase, the BET surface area is from 10 to 200 m2/g, and the volume of 2 to 50 nm pores is from 0.4 to 2.5 ml/g; and after heating at 900° C. for a period of 4 hours, the anatase proportion is more than 50% of the room temperature proportion, the BET surface area is at least 60% of the room temperature BET surface area, and the volume of 2 to 50 nm pores is at least 50% of the room temperature volume.