Synchronous regulation of morphology and crystal phase of TiO2 via a facile green hydrothermal approach and their photocatalytic activity

Morphology and crystal phase regulation of TiO2-base semiconductors via facile green synthesis approaches is promising and challengeable. Herein the synchronous regulation of morphology and crystal phase of TiO2 was achieved in the presence of OA in an aqueous solution. TiO2 nanorod, nanosphere composed of nanoparticles, and dandelion-like microsphere were obtained with the variation of the molar ratio of OA and TTIP. Moreover, the crystal composition of anatase/rutile could be regulated via adjusting the reaction duration and temperature and the molar ratio of TTIP/OA. The results showed that the photocatalytic activity was highly associated with the morphology and crystal phase composition. The dandelion-like microspheres with crystal composition of anatase/rutile = 0.73/0.27 exhibited the highest photocatalytic performance, due to the specific architecture and optimal crystal phase composition. The specific architecture facilitates the transfer of reactants and the biphase TiO2 promotes the separation efficiency of photogenerated electrons and holes, resulting to high photocatalytic performance.