Improving ZnAl2O4 structure by using chelating agents

In this paper, ZnAl2O4 spinel powders were prepared by a sol–gel route using zinc nitrate and aluminium nitrate in polar solvent (e.g. water) as the starting materials from the viewpoint that they are low-cost. A study of the effect of chelating agents such as sucrose (S), citric acid (CA) and triethanolamine (TEA) with a different weight ratio on the structure of ZnAl2O4 is reported. The characterization of the synthesized ZnAl2O4 powder was performed by XRD, FT-IR, Diffuse reflectance spectroscopy (DRS) and scanning electron microscopy (SEM). The results show that the powders made by the weight ratio 1:4 (metal:chelating agent) had a better morphological structure than the other weight ratios (1:1 and 1:2). Crystallite sizes vary from 16 nm for ZAO(S) up to 26 nm for ZAO(TEA). It was found that crystallite size, specific surface area and morphology are strongly dependent on the chelating agent/metal ratio and kinds of chelating agents.

► Effect of sucrose, citric acid & TEA on the structure of ZnAl2O4 was investigated.
► Different ratio of M:chelating agent (1:1; 1:2; 1:4) were used.
► Increasing ratio of chelating agent to metal causes decreases size of particles.
► ZAO prepared by Sucrose has lower size and many pores.