Escalab 250xi x ray photoelectron spectroscopy xps

Mineralogical characterization of soil samples was performed using an X-ray diffractometer (XRD) (Rigaku D/max-2500 PC, Rigaku Industrial Corp., Tokyo, Japan), operating with Cu Kα radiation at 40 kV and 150 mA, scanning over the range 10–90° in 2θ, step size 0.02°. To analyze the overall size distribution and morphology of soil particles, and elemental composition, a scanning electron microscope (SEM) (S-4800, Hitachi, Tokyo, Japan) equipped with X-ray energy dispersive spectrometer (EDS) was used. The elemental analysis by EDS was performed in “point mode” in which the beam was positioned on a manually selected single area on SEM image [15 (link),16 (link)]. Chemical states of Cr on the surface of soil samples before and after leaching were determined using an ESCALAB 250Xi X-ray photoelectron spectroscopy (XPS) (Thermo Fisher Scientific, Waltham, USA) with an Al Kα X-ray source at a base pressure of 10⁻⁹  mbar. To compensate for surface charge effects, binding energies were calibrated using the C 1s hydrocarbon peak at 284.8 eV. A narrow scanned spectra in the range of 567–596 eV was used to obtain the redox state information for the Cr. Peak fitting procedure and quantitative calculations of the surface atomic concentration of Cr were performed using XPS Peak software (version 4.1).

The powder X-ray diffraction (XRD) patterns were performed on a Panaco X′ Pert PRO X-ray diffractometer with Cu Kα radiation (l = 0.15406 nm) with the operation voltage and current maintained at 45 kV and 40 mA. Scanning speed: 1° min⁻¹, test range: 10° ≤ 2θ ≤ 70°. Fourier transform infrared spectroscopy (FT-IR) analysis was carried out on a PerkinElmer FT-IR spectrometer. The scanning electron microscope (SEM) images were determined by Zeiss MERLIN Compact SEM-EDX microanalysis. TEM images and elemental mapping analysis of the samples were obtained on a FEI Talos F200S transmission electron microscope operating at 200 kV. The chemical states of different elements were determined by Thermo ESCALAB 250XI X-ray photoelectron spectroscopy (XPS). The UV-vis absorption spectra of the samples were measured on Shimadzu UV-1780 UV-vis-NIR spectrophotometer. The absorbance of the solution during the reaction was monitored by a 722N visible spectrophotometer.

The morphologies of the nanoparticles were observed by transmission electron microscopy (TEM, JEM-2100F, JEOL, Tokyo, Japan). A chemisorption–physisorption analyzer (TriStar II3020, Micrometrics, Norcross, GA, USA) was used to measure the structural parameters of Janus-MMSN by nitrogen adsorption/desorption analysis at 77 K. The Brunauer–Emmett–Teller (BET) method was applied to evaluate the specific surface area of the samples, and the Barrett–Joyner–Halenda (BJH) method was applied to calculate the pore size distributions. Fourier transform infrared (FTIR) spectra were collected using an IRPrestige-21 Fourier spectrophotometer with KBr pellets (Shimadzu, Tokyo, Japan). MiniFlex600 powder X-ray diffraction (XRD, Rigaku, Tokyo, Japan) patterns were recorded using Cu-Kα radiation (λ = 1.54056 Å, (0.02°·min⁻¹ in the 10–80° range). The magnetic properties of the nanoparticles were examined using a Lake Shore 7404 vibrating-sample magnetometer (USA). ESCALAB 250XI X-ray photoelectron spectroscopy (XPS, Thermo Fisher, Waltham, MA, USA) was used to determine the surface composition of the nanoparticles. The dynamic light scattering (DLS) and zeta potential measurements were conducted using a Zetasizer Nano instrument (Malvern Instruments, Malvern, UK) to detect the size, particle size distribution (polydispersity index, PDI), and zeta potential of the nanoparticles.