2.3 | Structural characterizations
The X-ray diffraction (XRD) patterns were performed on Rigaku D/MAX 2500/PC with Cu Kα radiation (λ=0.154 nm at 40 kV and 200 mA). The patterns were collected from 2° to 50° with a 5° min-1scan speed at a normal pressure and room temperature. For thermogravimetric (TG) measurements, samples were treated with a heating rate of 10°C min-1 from 40°C to 750°C on a Netzsch STA 449F3 instrument under a 20 mL min-1 of N2 flow. Fourier Transform Infrared (FTIR) spectra from 400 to 4000 cm-1 were recorded on a Thermofisher Scientific Nicolet iS50 spectrometer.