were obtained using a SUPRA 55VP instrument (Carl Zeiss, Germany).
X-ray diffraction (XRD) patterns were recorded using a SmartLab 9
automated multipurpose X-ray diffractometer (Rigaku, Japan) with Cu
Kα radiation (λ = 1.54056 Å). X-ray photoelectron
spectroscopy (XPS) measurements were performed using an ESCALAB 250Xi
X-ray photoelectron spectrometer (Thermo Fisher Scientific, USA).
Fourier-transform infrared (FT-IR) spectra were recorded using a Nicolet
380 FT-IR spectrometer (Thermo Fisher Scientific, USA) with KBr as
the background. Raman spectra were obtained using a Renishaw in Via
confocal Raman microscope. Thermogravimetric analysis (TGA) was conducted
with a TGA/DSC 1 instrument (Mettler Toledo, Switzerland). UV–vis
spectra were obtained using a UV-2600 double beam UV spectrophotometer
(Golden Island, Japan).