Synthesis and Visible Light Photocatalytic Activity of Nitrogen-Doped TiO2/HTi2NbO7 Nanosheet Nanocomposite

The nitrogen-doped nanocomposite based on TiO2 nanoparticles and HTi2NbO2 nanosheets was successfully synthesized by the following procedures: Layered CsTi2NbO2 was firstly prepared by high temperature solid-state method, and then treated with HNO3 solution to obtain layered HTi2NbO7 by proton-exchange reaction. The resulted layered HTi2NbO7 was well dispersed in tetrabutylammonium hydroxide (TBAOH) solution in order to prepare HTi2NbO7 nanosheets by exfoliation reaction and then freeze-dried treatment. Finally, to prepare nitrogen doped TiO2/HTi2NbO7 nanosheets (denoted as N-TTN) nanocomposites, the mixtures of the freeze-dried HTi2NbO7 nanosheets and titanium(IV) isopropoxide were calcinated in the presence of urea as N source. The as-prepared samples were characterized by X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), photoelectrochemical properties measurements, UV-Vis spectroscopy as well as N-2 adsorption-desorption measurements. It was found that anatase TiO2 nanoparticles were well-distributed on the surface of HTi2NbO7 nanosheets, resulting in the formation of heterojunction structure between two components. The photocatalytic activities of samples were evaluated by the photodegradation of rhodamine B (RhB) under visible light irradiation. It indicated that the resultant N-TTN nanocomposite showed a highest photocatalytic activity toward the degradation of RhB, owing to the synergistic effects of nitrogen doping, the formation of heterojunction, increased specific surface area and rich mesoporous structure.