**2.2.3 Fourier transform infrared spectroscopy (FT-IR)**

Fourier transform infrared spectroscopy (FT-IR) analysis of dried and annealed powders were carried out in an Impact 400, Nicolet spectrometer in the wavenumber range 400–4000 cm-1 at resolution of 4 cm-1 for studying the chemical groups. For this analysis, KBr pellets were pressed to hold the samples to be analyzed.
