A facile solvothermal approach was used to prepare brookite-type TiO2 nanocrystals with different phase content and structure, accomplished by adjusting the ratio of TiCl (4) to t-BuOH. The obtained biphasic brookite/rutile TiO2 nanocrystals showed a high brookite weight content (72%). The photocatalytic degradation of phenol under UV-irradiation was used to determine the synergetic effect from the combination of different phases (e.g., brookite, anatase, and rutile). The biphasic NST-4 composed of brookite and rutile exhibited the highest degradation rates, with rate constants three times higher than commercial Degussa P-25. Detailed analysis found that, besides phase composition and content, the semi-embedded structure was essential to obtain a superior activity of biphasic TiO2 samples. (C) 2015 Elsevier B.V. All rights reserved.