Synthesis and characterization of nanosized zinc aluminate spinel from a novel Zn-Al layered double hydroxide precursor

In this paper, a novel Zn-Al layered double hydroxide (LDH) with composition [ZnAl2(OH)(6)]CO3 center dot nH(2)O was prepared using the urea method. The results of X-ray diffraction (XRD) and transmission electron microscopy (TEM) confirmed its layered crystalline structure. Nanosized zinc aluminate spinel was successfully synthesized by calcining [ZnAl2(OH)(6)]CO3 center dot nH(2)O at the temperatures 700 degrees C or above. The formation of ZnAl2O4 was monitored via XRD, Fourier transform infrared spectroscopy (FTIR), thermogravimetric and differential thermal analysis (TG-DTA). The optical and textural properties of the Zn-Al LDH and its calcined products were studied via UV-vis diffuse reflection spectroscopy and nitrogen sorption analysis. The band gap value of the sample calcined at 900 degrees C is in the range of 3.8-4.0 eV and the specific surface area decreases with increasing calcination temperatures. (C) 2012 Elsevier B.V. All rights reserved.