Controllable synthesis and morphology-dependent photocatalytic performance of anatase TiO2 nanoplates

Abstract

Uniform rhombic anatase TiO₂ nanoplates with selectively exposed {010} facets were successfully fabricated using a novel solvothermal method without adding surfactant or templates. In our synthetic approach, the coordination effect of acetic acid (HAc) and N,N-dimethyl formamide (DMF) regulated the reaction rate and contributed to the formation of TiO₂ nanoplates. The TiO₂ samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), infrared spectra (IR), UV-visible diffuse reflectance spectroscopy (DRS), Brunauer–Emmett–Teller (BET) specific surface areas and photoluminescence spectra (PL). The TEM characterization results suggested that the growth of rhombic nanoplates was governed by a nucleation–crystallization–dissolution growth mechanism. The mechanism demonstrated that both the reaction time and the HAc/DMF ratio played crucial roles in controlling size and shape of TiO₂ nanocrystals. By tuning the ratio of HAc to DMF, reaction time and reaction temperature, the photocatalytic performance of the as-synthesized TiO₂ samples was improved. The enhanced photocatalytic activity could be ascribed to the exposed {010} facets and the high surface areas of the TiO₂ nanoplates.