Anatase TiO2 mesocrystals with exposed (0 0 1) surface have been successfully synthesized by a facile one-step solvothermal method using NH4F as the structure regulator in glacial acetic acid environment. The exposed (0 0 1) surface of the obtained anatase TiO2 mesocrystal was consisted of numerous nanocrystals with exposed {0 0 1} facet. The results indicated that both the added amount of NH4F and solvothermal reaction time played significant roles in the formation of anatase TiO2 mesocrystals with exposed (0 0 1) surface. A possible formation mechanism of anatase TiO2 mesocrystal with exposed (0 0 1) surface was proposed based on the experimental data. As UV active photocatalysts, the resultant anatase TiO2 mesocrystals were evaluated in detail by photocatalytic decomposition of gaseous styrene. The results demonstrated that the anatase TiO2 mesocrystals fabricated by solvothermal treating a mixture of 0.50 g NH4F, 2.50 mL Ti(OC4H9)(4) and 50 mL of glacial acetic acid at 210 degrees C for 24h exhibited the highest photocatalytic activity to the decomposition of styrene. This is due to the synergistic effects of excellent crystallinity, high energy {0 0 1} crystal facets, relatively large surface area, enhanced bandgap energy and unique mesoporous structure. (C) 2013 Elsevier B.V. All rights reserved.