A comparative study on citrate sol-gel and combustion synthesis methods of CoAl2O4 spinel |
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Authors: | Jafar Baseri Rahim Naghizadeh Hamid Reza Rezaie Farhad Golestanifard Mohammad Golmohammad |
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Affiliation: | 1. School of Metallurgy and Materials Engineering, Iran University of Science and Technology, Tehran, Iran;2. Renewable Energy Department, Niroo Research Institute, Tehran, Iran |
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Abstract: | CoAl2O4 spinel was successfully synthesized by combustion synthesis method using glycine and urea by 1:1 molar ratio as fuels and sol-gel process using citric acid as a chelating agent. The as-synthesized powders were calcined at desired temperatures to obtain CoAl2O4 spinel as a single phase. X-ray diffraction, thermogravimetric, and differential thermal analysis results revealed that the formation of CoAl2O4 spinel in combustion method needs 300°C higher temperatures than those of sol-gel. Scanning electron microscopy and transmission electron microscopy analysis results revealed that “sol-gel spinel” had nanometric particle size which was smaller than those of “combustion spinel.” Temperature programed reduction with hydrogen and Fourier transform infrared spectroscopy results declared that there was a little residual cobalt oxide in combustion spinel while there is no oxide resided in “sol-gel spinel.” Consequently, the sol-gel method has more benefit in synthesizing spinel with sulfate precursors than combustion. |
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Keywords: | calcination CoAl2O4 spinel combustion method sol-gel process |
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