Super x eds detector

For further characterization of the early stages
of calcium phosphate
precipitation in the presence and absence of citrate, samples were
collected from the reaction media at different reaction times, quenched
in ethanol, transferred onto carbon-coated copper grids, and observed
using a 30 μm objective aperture in a FEI TEM Titan working
at 300 kV. SAED patterns were collected using a 10 μm aperture,
which allowed the collection of diffraction data from a circular area
∼0.2 μm in diameter. Elemental compositional maps were
obtained in the STEM mode using a Super X EDS detector (FEI), formed
by four SSD detectors with no window surrounding the sample. STEM
images in the FEI Titan TEM of the areas analyzed by EDS were collected
with a high-angle annular dark field detector. At the end of each
titration experiment, the solution was separated from the reaction
media by filtration (Nucleopore, Ø = 200 nm),
and the solids collected were studied by X-ray diffraction (PANalytical
X’Pert Pro X-ray, Cu Kα radiation, λ = 1.5405 A°,
3°–50° 2θ range, scanning rate of 0.11°
2θ s^–1), FTIR (ATRproONE-FTIR, Jasco Model
6600, frequency range of 400–4000 cm^–1, resolution
of 2 cm^–1, and 100 accumulations), FESEM (Zeiss
SUPRA40VP), and TEM (FEI Titan, 300 kV).

The morphology and structure of HPDA were investigated by transmission electron microscopy (TEM, Talos F200s, FEI, USA). Elemental information of HPDA was characterized by energy-dispersive X-ray spectroscopy (EDX, Super-X EDS Detector, FEI, USA). In addition, the surface area and pore size distribution of HPDA were determined by a Brunauere Emmette Teller (BET, ASAP 2460 3.01, Micromeritics, USA) and the specific surface area (S_BET) and mean pore diameter were calculated by using the BET theory [56 (link)]. Total pore volume was calculated based on liquid nitrogen adsorbed at P/P0 = 0.99. The Barrett–Joyner–Halenda (BJH) theory was used to determine the pore size distribution from the nitrogen adsorption values.

To clarify various properties of prepared materials, photocatalysts were characterized with the use of numerous pieces of advanced equipment. The morphologies of materials were observed using an FEI Talos F200s (USA) transmission electron microscope, equipped with high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and an FEI Super-X EDS detector (USA). The mineral composition of the synthesized material was measured by XRD patterns using a Shimadzu XD-3A diffractometer (Japan), employing the radiation of Cu-Kα (λ = 1.54056 Å). In addition, the surface chemical compositions of the catalysts were examined with a PHI 5000 VersaProbe X-ray photoelectron spectrometer (USA). The optical properties of the photocatalysts were detected by UV-Vis spectroscopy using a PerkinElmer Ultraviolet spectrophotometer (Shanghai, China). Additionally, the active species in the photocatalytic system were analyzed by electron spin resonance using an electron paramagnetic resonance spectrometer (EMXmicro-6/1/P/L, Karlsruhe, Germany), and the DMPO (5,5-dimethyl-1-pyrroline N-oxide) was selected as the capturing agent to trap the free radicals of ^•O₂⁻ and ^•OH. Electrochemical impedance spectroscopy was conducted and photocurrent were measured with a CHI 660E electrochemical workstation (Shanghai, China).