Synthesis and characterization of spinel-type zinc aluminate nanoparticles by a modified sol–gel method using new precursor

Abstract In the present paper, we report the successful synthesis of spinel-type of zinc aluminate (ZnAl 2 O 4 ) nanoparticles by a modified sol–gel method. Aluminum nitrate and Zn(en) 2 + complex (en: ethylenediamine) as new Zn 2+ source were used. Diethylene glycol monoethyl ether and citric acid are employed as solvent and chelating agent. This method starts from the precursor complex, and involves formation of homogeneous solid intermediates, reducing atomic diffusion paths during thermal treatment. ZnO and ZnAl 2 O 4 nanocrystals were obtained when the precursor was heat-treated at 350 °C in air for 2 h. The stages of the formation of ZnAl 2 O 4 , as well as the characterization of the resulting compounds were done using thermo-gravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR). The structure, particle size, and temperature of formation of ZnAl 2 O 4 phases were found to depend on the precursors and methods used for preparation and the calcination temperature. The lowest temperature for preparation of the ZnAl 2 O 4 is about 550 °C.