The surface-fluorinated TiO₂ crystal dominated with high energy {001} facets was synthesized by using hydrofluoric acid as capping agent which plays an exceedingly important role in controllable synthesis of 3D flower-like microstructures by self-assembling ultrathin nanosheets. The evolution of introduced fluoride species on the surface of TiO₂ was studied when annealing temperature was continuously elevated in air atmosphere. X-ray diffraction results show that the as-prepared TiO₂ is very stable and without phase transformation even calcination at 700 °C. Both Scanning Electron Microscope and Transmittance Electron Microscope techniques reveal that the TiO₂ nanosheets are intact before calcination but are etched and form some square-like pores after calcination. Moreover, the change of fluoride species in TiO₂ is discussed with the assistance of X-ray Photoelectron Spectroscopy, Thermogravimetry-Derivative Thermogravimetry, Fourier Transform Infrared Spectroscopy, and Ultraviolet-Visible spectroscopy. The results indicate that the Ti-F species is originally physical adsorbed on the TiO₂ surface before calcination, then fluorine is interstitially doped in TiO₂ lattice calcined at 400−500 °C, and finally fluoride species is totally removed over 600 °C. Furthermore, the photocatalytic results show that the TiO₂ calcined at 500 °C has the highest photocatalytic activity and still maintain a stable durability after several recycles.

以氢氟酸为封端剂，合成了以高能{001}晶面为主的表面氟化TiO ₂晶体，它在通过自组装超薄纳米片可控地合成3D花状微结构中起着极其重要的作用。研究了在大气中不断提高退火温度的情况下，TiO ₂表面引入的氟化物种类的演变。X射线衍射结果表明，所制备的TiO ₂非常稳定并且即使在700℃下煅烧也没有相变。扫描电子显微镜和透射电子显微镜技术均显示TiO ₂纳米片在煅烧之前是完整的，但是在煅烧之后被蚀刻并形成一些正方形的孔。此外，借助X射线光电子能谱，热重分析-衍生热重分析，傅立叶变换红外光谱和紫外可见光谱等技术，讨论了TiO ₂中氟化物种类的变化。结果表明，在煅烧之前，Ti-F物种最初是物理吸附在TiO ₂表面，然后在400-500°C煅烧的TiO ₂晶格中间隙掺杂氟，最后在600°C时氟化物被完全去除。此外，光催化结果表明，TiO ₂ 在500°C下煅烧具有最高的光催化活性，并且在多次循环后仍保持稳定的耐久性。