Enhanced photocatalytic activity of TiO2/carbon@TiO2 core-shell nanocomposite prepared by two-step hydrothermal method

- TiO2/carbon@TiO2 nanocomposite was fabricated by a two-step hydrothermal method.
- The TiO2/carbon@TiO2 nanocomposite has high photocatalytic activity.
- TiO2 has high crystallinity and SOVs content after the second hydrothermal process.
- The carbon has a significant effect on its photocatalytic property.

A unique TiO2/carbon@TiO2 core-shell nanocomposite was fabricated by a two-step hydrothermal method. High-resolution transmission electron microscopy images show the size of the nanocomposites is about 50-100 nm, which are composed of well-defined crystallized titania on the shell with the TiO2/carbon composite as the core. The existence of the amorphous carbon in the core can be proved by Raman spectra and thermogravimetric analysis. X-ray diffraction pattern and Raman spectra show that the crystalline of TiO2 is improved after the second hydrothermal treatment and the TiO2 are the pure anatase phase. Measurements of the photocatalytic degradation of rhodamine B show that the photocatalytic activity of TiO2/carbon@TiO2 core-shell nanocomposite is higher than that of the initial TiO2/C core and pure TiO2 because TiO2 on the shell has high crystallinity and high content of surface oxygen vacancies (SOVs) after the second hydrothermal treatment. Moreover, the synergistic catalytic effect of the carbon in the core can also enhance the photocatalytic activity of the nanocomposite, such as retarding the recombination of photo-generated electron-hole pairs and absorbing more light.