Escalab 250xi

The crystal structures of Al-doped ZnO and Al-doped ZnTe were examined using X-ray diffraction (XRD) (Mac Science, Kanagawa, Japan, M18XHF using Cu Ka radiation, λ = 0.15406 nm). The morphologies of the electrodes were investigated using field-emission scanning electron microscopy (FESEM) (JEOL, Tokyo, Japan, JMS-7401F and Phillips Electron Optics B.V. XL30S FEG, operated at 10 keV) and high-resolution transmission electron microscopy (HR-TEM) (JEOL, Tokyo, Japan, JEM-2200FS), combined with an energy dispersive X-ray spectrometer operated at 200 kV. The elemental compositions and their oxidation states were investigated using X-ray photoelectron spectroscopy (XPS) (Thermo Fisher Scientific, Waltham, MA, USA, ESCALAB 250Xi) and the binding energy of each element was calibrated with respect to the carbon 1 s peak at 284.8 eV. The absorbance of photoelectrodes was examined using UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS) (Shimadzu, Kyoto, Japan, UV2501PC).

The structures of the VHCF powder and cathode electrodes were studied by powder X-ray diffraction (XRD) tests using an X-ray diffractometer (D/MAX-Ultima, Shimadzu Corporation, Kyoto, Japan) with Co K_α radiation at room temperature. The valence states of the elements in the VHCF cathodes were studied by X-ray photoelectron spectroscopy (XPS) spectra using an X-ray photoelectron spectrometer (ESCALAB 250Xi, Shimadzu Corporation, Kyoto, Japan). The microstructure of the VHCF powder was observed by means of scanning electron microscopy (SEM) using a field-emission microscope (SUPRA 55 SAPPHIRE, Carl Zeiss Corporation, Jena, Germany). The element distribution in the VHCF sample was detected by the above field-emission microscope equipped with an energy dispersive spectrometer (EDS). The microstructure of the sample was checked by means of transmission electron microscopy (TEM) and high-resolution TEM (HRTEM) measurements using an electron microscope (JEOL: 2100F, Joel Corporation, Tokyo, Japan). The thermal gravimetric (TG) curve was conducted using a thermal gravimetric analyzer (Mettler-Toledo, Zurich, Switzerland) in the air at a heating speed of 10 °C min⁻¹.

The morphology and structure of the product were characterized using a scanning electron microscope (SEM, JEOL, JSM-7000F) and a transmission electron microscope (TEM, JEOL, JEM-2100 with an accelerating voltage of 200 kV). The HAADF-STEM image and energy-dispersive spectroscopy elemental mapping of the product were obtained by scanning transmission electron microscopy (STEM, JEOL, JEM-ARM 200F). The chemical composition of the product was characterized using X-ray diffraction (XRD, Bruker), X-ray photoelectron spectroscopy (XPS, Thermo Fisher Scientific, ESCALAB 250Xi+) and Inductive Coupled Plasma Emission Spectrometer (ICP, SHIMADZU, ICPE-9000). The In situ UV spectroscopy measurements were characterized using Ultraviolet–visible spectroscopy (UV, Shimadzu, UV-60).