The X-ray diffraction (XRD) patterns were recorded using a Philips PW1700 diffractometer (Netherlands, Cu Kα). The transmission electron microscope (TEM) and high resolution-TEM (HR-TEM) images were performed using JSM-2100 (JEOL, Japan). Fourier transforms infrared (FT-IR) spectra were recorded using a Nicolet model 6700 spectrophotometer (Thermo Fisher Scientific, USA). X-ray photoelectron spectroscopy (XPS) spectra were recorded using a Thermo Fisher (K-alpha, Al Kα radiation). The thermogravimetric analysis (TGA) was performed using PerkinElmer TGA T60 under a nitrogen atmosphere. Nitrogen adsorption-desorption isotherm was recorded using Quantachrom (Model Nova 3200, USA) at 77K. 1 H NMR spectra were recorded using 500 MH (JEOL, Japan). Gas chromatography-mass spectrometry was performed using GC-MS (Thermo Scientific) connected to a single quadrupole mass spectrometer (ISQ 7000). The mass spectra were recorded using electron impact mode. The UV-Vis diffuse reflectance spectroscopy (DRS) of solid samples was measured using the Evolution 220 spectrophotometer (Thermo Fisher Scientific, UK).