Preparation of Fe2O3-ZnO Nanocomposites: Structure and Optical Properties

The synthesis of Fe2O3/ZnO has gained acceptance in few years due to its magnetic, photoluminescence and catalytic properties and also, as active element in gas sensors. This type of composite particles has biological and biomedical potential applications such as detection of cancer cells, bacteria and viruses, and magnetic separation. In the present study, first we have synthesized the Fe2O3/ZnO nanoparticles and then structural, optical and surface morphological properties are investigated by XRD, HRTEM, FESEM, XRF and FTIR analyses. Fe2O3-ZnO nanoparticles were fabricated by a solgel synthesis by iron chloride hexahydrate and zinc sulfate heptahydrate. At the beginning, 2g of Polyvinylpyrrolidone (PVP) stabilizer was dissolved in 100 mL dionized water and then 5 g FeCl3 was added to the solution with stirring at room temperature. Then 5g of ZnSO4 was added to the solution and synthesis temperature was increased to 100oC. The product were evaporated for 3 hours, cooled to room temperature and finally calcined at 600oC for 3 hours. The XRD results showed single-phase Fe2O3-ZnO nanocomposits with a hexagonal wurtzite structure of ZnO and spinel phase of rhombohedral α-Fe2O3. The crystallite size of as-prepared sample was determined about 45 nm and annealed one was calculated around 40 nm. The SEM images showed the Fe-Zn nanoparticles change from spherical shape to rod-shape by increasing temperature after annealing. The TEM studies showed the core-shell nanoparticles with mean diameter of 47 nm. The sharp peaks in FTIR spectrum determined the stretching vibrations of Fe and Zn groups in the frequencies of 620, 565 cm-1 and 410 cm-1. The XRD data indicates single-phase Fe2O3-ZnO structure. The SEM images shows that the nanoparticles changed from sphere-like shaped to rod-like shaped by increasing annealing temperature. TEM image exhibits the core-shell Fe-Zn nanoparticles with an average diameter about 37 nm. From the FTIR data, it is shown the presence of Fe-Zn stretching mode and the intensity of the peaks increased by increasing annealing temperature. XRF analysis showed peaks of iron and ferrite elements and an increasing of the Zn weight percent were observed from 26.35 %Wt. to 49.26 %Wt., by increasing temperature.