obtained by using a Shimadzu UV-1900 spectrophotometer. SEM images
were obtained by using a JEOL JSM-7610F field emission instrument.
TEM images were obtained by using a JEOL JEM-2100 field emission TEM.
The STEM images were captured with a high-angle annular dark-field
(HAADF) detector. Energy-dispersive X-ray spectroscopy (EDS) is affiliated
with TEM. The X-ray diffraction (XRD) patterns of the samples were
obtained using an X-ray powder diffractometer (Rigaku TTRAX III).
XPS analysis was obtained using a high-resolution electron spectrometer
(ULVAC-PHI).