Growth and photocatalytic performance of carambola-like TiO2 consisting of nanosheets exposed {001} facets

Carambola-like TiO2 consisting of nanosheets with exposed {001} facets was synthesized via a one-step solvothermal method for the first time. The carambola-like TiO2 was characterized by X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, and Brunauer-Emmett-Teller nitrogen adsorption isotherm experiments. The formation mechanism of the carambola-like TiO2 is discussed by investigating the effect of reaction time, temperature and the volume of hydrofluoric acid. The results from different growth stages demonstrated that the formation of carambola-like TiO2 included alcoholysis of precursor to nucleation, nuclei growth, dissolution-recrystallization growth and further growth. Reaction temperatures affected the morphologies and surface areas of carambola-like TiO2 samples. The photocatalytic performances of samples prepared at different temperatures were tested. The carambola-like TiO2 sample prepared at 160 degrees C exhibited the best photocatalytic activity. Such enhanced photocatalytic performance is ascribed to the large surface area and the exposed {001} facets with high activity.