Synthesis and characterization of nanocrystalline MgAl2O4 spinel via modified sol–gel method

Abstract

Nanocrystallines of magnesium aluminate spinel (MgAl2O4) were synthesis by modified sol–gel method using aluminum nitrate, magnesium nitrate, citric acid and diethylene glycol monoethyl ether were used as precursor materials with a molar ratio Al/Mg=2. After obtained a dry powder, the precursor was heat-treated in air at desired temperatures (700–900°C) for 2h. The formation nanocrystallines of MgAl2O4 spinel were characterization by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Thermal gravimetric and differential thermal analysis (TGA/DTA), Field emission scanning electron microcopy (FESEM) with the energy dispersive X-ray spectroscopy (EDX), High resolution transmission electron microscopy (HRTEM) and specific surface area of the synthesized powders was measured with a Brunauer–Emmett–Teller (BET) apparatus using N2 adsorption. According to obtained XRD patterns the formation of single phase MgAl2O4 completed up 700°C. The average crystallite’s sizes increased with increasing temperature of calcination, but the specific surface area spinels decreased. The average crystallite’s sizes spinel and specific surface area at 800°C were estimated about 11.07nm and 154m2g−1, respectively. The results of FESEM analysis show that the nanoparticles shape are as spherical shape, uniform and a little agglomerated. The dimension of nanoparticles used by HRTEM was measured to be about 12nm by averaging 20 particles at 800°C.