X ray photoelectron k alpha

The morphology of the samples was characterized with a Hitachi S-4700 Field Emission Scanning Electron Microscopy (FESEM) at an acceleration voltage of 15 kV and a Themis Z F-30 Double Cs Corrector Transmission Electron Microscope (TEM) at an acceleration voltage of 300 kV. Nitrogen adsorption/desorption test was carried out with a Micromeritics ASAP 2020 apparatus at 77 K. The S_BET was obtained using the Brunauer–Emmett–Teller (BET) method from adsorption data in the relative pressure (P/P₀) ranging from 0.05 to 0.3, and the total pore volumes were acquired from the amount of nitrogen adsorbed at a relative pressure of 0.99. The pore size distribution, micropore volume and mesopore volume were calculated from the nitrogen adsorption/desorption data using the Non-Local Density Functional Theory (NL-DFT) software (SAIEUS, Micromeritics Instrument) with a ‘Heterogeneous Surface’ model. The X-ray diffraction (XRD) measurements were performed on a Bruker D8 Advance diffractometer with Cu Kα radiation (k = 0.1542 nm, 40 kV). The Raman spectra were obtained by a Renishaw-inVia Confocal Raman Microscope using excitation wavelength at 514.5 nm. The chemical composition was studied by X-ray photoelectron spectroscopy (XPS) using a Thermo Scientific X-ray photoelectron (K-alpha).