Preparation and Photoelectrochemical Activity of Cr-Doped TiO2 Nanorods with Nanocavities

Cr-doped TiO 2 nanorods with nanocavities were synthesized by a facile hydrothermal treatment and heating in air. The samples were characterized respectively by means of X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), and X-ray photoelectron spectroscopy (XPS). XRD patterns indicated that all the samples were anatase crystalline. HRTEM results and the electron diffraction patterns illustrated that the TiO 2 nanorods possessed the single-crystalline structure. TEM images confirmed that there were different types of nanocavities inside the nanorods, such as a circle, hexagon, and rectangle. XPS results suggested that Cr elements were successfully doped into the TiO 2 nanorods after hydrothermal and most Cr congregated on the surface in the form of Cr 2 O 3 after heating. The optical properties of the samples were studied with a UV−vis spectrometer. The photoelectrochemical activity of the Cr-doped TiO 2 nanorods thin film was better than that of the commercial anatase TiO 2 particulate thin film. The high photoelectrochemical activity of the synthesized Cr-doped TiO 2 nanorods could be attributed to three factors: the doped Cr, one-dimensional nanostructure of the nanorod, and the increased light-harvesting abilities.