Hydrothermal synthesis and characterization of nanosized transition metal chromite spinels

Authors : Shahid Khan DURRANI, Syed Zahid HUSSAIN, Khalid SAEED

Pages : 111-120

View : 16 | Download : 5

Publication Date : 0000-00-00

Article Type : Research Paper

Abstract :Homogeneous crystalline transition metal chromite spinels insert ignore into journalissuearticles values(MCr2O4, where M = Co, Mn, and Ni); were prepared by hydrothermal reaction of aqueous solutions containing the respective metal nitrate, chromiuminsert ignore into journalissuearticles values(III); nitrate, and sodium hydroxide in stoichiometric amounts at 180-200 °C and pH 10.5-11.5 for 11-13 h. The crystalline structure, microstructure, and thermal stability of the synthesized chromite products were analyzed by X-ray diffraction insert ignore into journalissuearticles values(XRD);, scanning electron microscopy, thermogravimetry, and differential thermal analysis. The analysis results revealed that the CoCr2O4 and MnCr2O4 crystalline phases were thermally stable in the range of 750-800 °C. UV-visible studies showed that higher characteristic bands corresponded to the region of the visible spectrum of cobalt insert ignore into journalissuearticles values(CoCr2O4, bluish-green); and manganese-doped cobalt chromites insert ignore into journalissuearticles values(Co0.5Mn0.5Cr2O4, dark green);. XRD powder diffraction data of specimens revealed the formation of a well-crystallized spinel structure of transition metal chromite insert ignore into journalissuearticles values(approximately 98%); after calcination at 550-750 °C. The nanocrystallinity of synthesized CoCr2O4 was found to be in the range of approximately 100-120 nm.
Keywords : Hydrothermal synthesis, nanocrystalline, chromite, spinel, microstructure, X ray diffraction, thermogravimetry, differential thermal analysis