Quanta 250 feg electron microscope

The crystal structure of the sample was studied using an X-ray diffractometer (XRD, Ultima IV, Rigaku Ltd., Japan) with Cu-Kα radiation (λ = 0.15418 nm). Ultraviolet-visible diffuse reflectance spectroscopy (DRS) was performed using an ultraviolet-visible spectrophotometer (Shimadzu UV-2600, Japan), with BaSO₄ as the substrate, and the wavelength was between 200 and 800 nm. A field emission scanning electron microscope (FE-SEM, ZEISS Gemini-SEM 500, Germany) was used to explore the morphology of the sample. High-resolution transmission electron microscope (HR-TEM) images were obtained (FEI Quanta 250 FEG electron microscope, USA) with an acceleration voltage of 200 kV. A fluorescence spectrometer (G9800A, Japan) was used to obtain photoluminescence (PL) emission spectra of the samples, which were excited at 310 nm.