Modification and functional investigation of self-assembled two-dimensional TiO2 nanosheets with abundant hydroxyl groups

Self-assembled two-dimensional (2D) TiO2 nanosheets are only excited under UV light. They suffer from weak visible light absorption and fast recombination of photogenerated electron-holes carriers. In this paper, four kinds of functionalized modifications were realized through complexing self-assembled 2D TiO2 nanosheets with Fe3O4 nanoparticles, Fe2O3 nanoparticles, N doping, and combining with carbon quantum dots due to the large amount of hydroxyl groups present on the surface of the nanosheet, thereby forming the TiO2/Fe3O4, TiO2/Fe2O3, N-doped TiO2, and TiO2/C composites. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), and X-ray photoelectron spectroscopy (XPS) were used to characterize the synthesized products, confirming the successful synthesis of self-assembled 2D TiO2-based composites. By modification, the increasingly improved photocatalytic properties of self-assembled 2D TiO2 nanosheets are also presented. These findings may open up a new avenue and stimulate further research to prepare more self-assembled 2D TiO2-based composites.