<p>The adsorption, catalytic and photocatalytic properties of titania strongly depend on its phase composition, morphology and the presence of impurities. In this work, we report new data on the surface acidity and catalytic performance of anatase–brookite TiO₂ and compare them with data for a commercial anatase–rutile system (TiO₂ Degussa P25). Pure titania was synthesized by the sol-gel method using titanium (IV) isopropoxide as a precursor. It consisted of anatase–brookite nanoparticles, as revealed by XRD, Raman spectroscopy and SEM. The sample has a monomodal, mesoporous structure with well-defined pore size around 7.5&#xa0;nm. FTIR spectroscopy highlighted the impact of the bulk composition on the surface by identifying different hydroxyl groups associated with anatase and brookite TiO₂. For both titania samples, the adsorption of 2,6-dimethylpyridine showed the existence of Lewis acid sites and two types of Brønsted acid sites of different strengths, but the density of all types of acid sites was much higher for the synthesized TiO₂ polymorph. Anatase–brookite TiO₂ is more active and selective in the dehydration of isopropanol to propene than TiO₂ Degussa P25, which is associated with the significantly higher surface acidity of this catalyst.</p> Graphical Abstract <p></p>