2.3. Characterization of ZnO anchored SiO2 NPs
The amount of ZnO in ZSO-X was measured with ICP-AES with a
ICP-OES Optima 7000 DV Perkin Elmer instrument. Specimens for
the analysis were prepared by thinly grinding 0.2 g of powdered
samples and dissolving them in a Teflon beaker with 5 mL of HF
49%. Then the solution was dried and the residue rinsed five times
with 3 mL of HCl 37%. Finally, the obtained solution was dried
again, and the solid dissolved with MQ water and diluted in a
250 mL calibrated flask. Before analysis a further dilution 1:100
was carried out.
The presence of crystalline phases was assessed by conventional
XRD using a Bruker D8 Advance instrument, having a Cu
Ka incident beam (k = 1.5406 Å). The morphological characterization
of ZSO-X powders was performed on a Jeol 3010 High
Resolution Transmission Electron Microscope operating at 300 kV
with a high-resolution pole piece (0.17 nm point to point resolution)
and equipped with a Gatan slow-scan 794 CCD camera. The
powders were suspended in isopropanol, and a 5 lL drop of this
suspension was deposited on a holey carbon film supported on
3 mm copper grid for TEM investigation.