D8 focus powder

These as-synthesized nanocomposites were studied by various techniques. X-ray powder diffraction (XRD) patterns were collected by a German Bruker D8 Focus Powder (Fremont, CA, USA) using Cu Kα radiation. The scanning speed was setted to 4°/min. The specific surface area of these samples was calculated by the Brunauer–Emmett–Teller (BET) method and characterized by sorption using a Micromeritics Tristar 2000 instrument (Atlanta, GA, USA) at 77 K. Transmission electron microscopy (TEM, JEM-2100F, Tokyo, Japan) and selected area electron diffraction (SAED) patterns were operated at 200 kV. Field emission scanning electron microscopy (FE-SEM) images were obtained with a Hitachi S-4800 (Tokyo, Japan). UV–visible diffuse reflectance spectroscopy (DRS) was acquired on a UV-3101 PC Shimadzu spectroscope (Kyoto, Japan) at room temperature, and BaSO₄ was chosen as reference material. The photoluminescence (PL) spectra were recorded on a Hitachi F-4500 fluorescence spectrometer (Tokyo, Japan). X-ray photoelectron spectroscopy (XPS) was taken on a Thermo Scientific ESCALAB 250 spectrometer (Waltham, MA, USA) with a monochromatic X-ray line source of Al Kα radiation. All the binding energies were calibrated internally by setting C 1s to 284.6 eV. The surface molecular structural was studied by Fourier transform infrared (FTIR) spectroscopy (470 FI-IR, Medison, WI, USA).