Síntese e caracterização de Cr2O3 dopado com Fe pelo método sol-gel utilizando ácido cítrico como agente quelante

Abstract

In this work, was studied the synthesis of nanoparticles of Cr2O3 doped Fe using citric acid (C6H8O7) as chelating agent. The samples were prepared by slow addition of Cr(NO2) in 10mL of distilled water and then adding Fe(NO3) in 5 steps so that iron doping was 1%, 3%, 6%, 9% and 12% % respectively. The mixture was kept under constant magnetic stirring for 15 minutes at room temperature. The solutions were then heated at 100 °C for 72h to remove water, obtaining a xerogel. Finally, the obtained xerogel was calcined at a fixed temperature of 350 °C for 1h to produce the Cr2O3 particles. The results of the X-ray diffraction (XRD) revealed that the samples formed a single phase, the crystalline structure of the rhombohedral pattern belonging to the R-3C space group. The average sizes of the crystallites calculated from the XRD standards using the Scherrer equation and the Size-Strain Plot method became larger with the increase of the iron concentration in the solution, as well as the increase in the amplitude of the diffraction peaks and the narrowing of the width of the peaks in which it is directly related to the degree of crystallinity of the structure.