Organic small molecule-assisted synthesis of high active TiO2 rod-like mesocrystals

Mesocrystals have received considerable attentions due to their novel structure, property and nonclassical crystallization process. In the present work, rod-like TiO2 (A) mesocrystals with high specific surface area and excellent photocatalytic activity have been synthesized through a facile and mild solvothermal route. The mesocrystal products are believed to be formed through an oriented-attachment formation mechanism. Based on a series of contrast experiments, the oriented attachment of TiO2 nanoparticles is found to be carried out under the synergism of hydrophobic bonds, pi-pi interactions and "mixed-esters-templates''. Also the growth of the crystal facet of anatase is found to be affected by the pi-pi interaction. The present study not only opens new avenues for rationally designing TiO2 mesocrystal materials with ideal hierarchy and controllable sizes, but also offers a promising opportunity to understand the formation process of these unique porous-crystalline superstructures.