Study On Synthesis Of Co/Fe Spinel Ferrites Nanoparticles From Co/Fe-LDH Microcrystallites With The Method Hard-Templet

Spinel ferrites is a kind of antiquity with extensive use material. Being a kind of magnetic materials possessing many characters, ferrite has been applied in magnetic recorders, magnet, magnetic liquid, and microwave materials and so on. At the same time, as a sort of composite oxide, ferrite has many applications, such as catalysis and environmental protection.In the work, some materials are used as hard-templet such as fiber, degreased popped-corn and SBA-15, and Co(II)Fe(II)Fe(III)-LDHs were synthesized in using co-precipitate method. All tasks as follows:1. The CoFe₂O₄ is synthesized from Co(II)Fe(II)Fe(III)-LDHs use fiber as hard-templet. Co(II)Fe(II)Fe(III)-LDHs is successfully synthesized on the surface. Some micron-tubes and nanoparticles of Co/Fe spinel ferrite were obtained by temperature programming. The micron-tubes and nanoparticles were characterized by X-ray diffractions, Fourier transform infrared spectroscopy (FT-IR), Simultaneous Thermo-gravimetric and differential thermal analysis (TG-DTA), Scanning electron microscopy (SEM), Mossbauer spectroscopy. The results of the testing indicate that with the new method using fiber as hard-templet LDHs is successfully synthesized and its' soft magnetic is very well.2. Degreased popped-corn is used as hard-templet through the process of synthesize Co(II)Fe(II)Fe(III)-LDHs. The LDHs is synthesized both in and on the surface of the degreased popped-corn. When the calcined temperature was increased from 300-900℃, the Co(II)Fe(II)Fe(III)-LDHs was changed in the crystal structure, and formed Co/Fe spinel ferrite. From TEM there are lots of microporous pore was made. Combined the XRD with BET, indicate that the microporous isn't structural pore but sub-pore.3. SBA-15 is one of the materials that of tall pore volume and big BET surface area. Take it as hard-templet to synthesize Co(II)-Fe(II)-Fe(III)-LDHs. Testing by BET the surface area of the compound is smaller than the pure SBA-15, it is because that the LDHs is inside the pore of the SBA-15 and the pore diameter is became smaller than the SBA-15 with nothing in the pore. While the pore volume of the compound is bigger than the SBA-15 because of the accumulation of LDH. The pore of accumulate of LDHs is much bigger than the pure SBA-15, so the pore volume of the compound is much bigger than the pure SBA-15.