A nonaqueous sol–gel route to highly water dispersible TiO2 nanocrystals with superior photocatalytic performance

In this study, we report that highly water dispersible TiO 2 nanocrystals could be synthesized via a facile nonaqueous sol–gel method using titanium tetrachloride and ethanol as the precursors. The resulting TiO 2 samples were 5–10   nm in diameter according to characterizations with X-ray diffraction, transmission electron microscopy, and high resolution transmission electron microscopy. X-ray photoelectron spectroscopy, thermal gravimetric analysis, and Fourier-transform infrared spectroscopy analysis revealed that carbonaceous species were formed and bound on the surface of TiO 2 nanocrystals during the synthesis. These carbonaceous species could prevent the agglomeration of TiO 2 nanocrystals and endow the TiO 2 nanocrystals with highly water dispersible property and superior photocatalytic activity on the degradation of organic pollutant under visible light irradiation. We believe that the resulting TiO 2 nanocrystals with highly water dispersibility and superior photocatalytic activity could find wide applications in many fields.