Rapid and Continuous Production of Ferrite Nanoparticles by Hydrothermal Synthesis at 673 K and 30 MPa
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- 作者：Toshiyuki Sato ; Kiwamu Sue ; Wataru Suzuki ; Muneyuki Suzuki ; Keitaro Matsui ; Yukiya Hakuta ; Hiromichi Hayashi ; Kunio Arai ; Shin-ichiro Kawasaki ; Akiko Kawai-Nakamura ; Toshihiko Hiaki
- 刊名：Industrial & Engineering Chemistry Research
- 出版年：2008
- 出版时间：March 19, 2008
- 年：2008
- 卷：47
- 期：6
- 页码：1855 - 1860
- 全文大小：252K
- 年卷期：v.47,no.6(March 19, 2008)
- ISSN：1520-5045
文摘
Ferrite nanoparticles from Fe(NO3)3 and Me(NO3)2 (Me = Ni, Cu, Zn) aqueous solutions could be synthesizedcontinuously with a flow reactor at 673 K, 30 MPa, and 4 s residence time. The particles were characterizedby TEM, XRD, and ICP to obtain sizes, crystal structures, lattice parameters, and Me/Fe molar ratios. Solid-solution nanoparticles of MeFe2O4 and 
-Fe2O3 with a cubic spinel structure and an average particle sizeunder 10 nm were obtained. Conversion of Fe3+ was more than 0.97 at the given residence time, and conversionsof Me2+ increased from 0 to 0.62 with increasing residence time. The particle size increased with increasingresidence time, and no significant difference in divalent cations was observed. The Me/Fe molar ratio in theobtained solid-solution nanoparticles of MeFe2O4 and -Fe2O3 increased with increasing residence time andKOH molality. The Me/Fe molar ratio also increased in the order Zn < Cu < Ni at a given residence time,and this trend could be explained on the basis of ZnO, CuO, and NiO solubilities. The increase of the sizeand the Me/Fe molar ratio in the obtained particles with increasing residence time shows that, in the formationmechanism, primary solid-solution particles with low Me/Fe molar ratios probably nucleated and, after surfacedissolution of the particles, dissolved Fe3+ recrystallized on the surface with incorporation of Me2+.
-Fe2O3 with a cubic spinel structure and an average particle sizeunder 10 nm were obtained. Conversion of Fe3+ was more than 0.97 at the given residence time, and conversionsof Me2+ increased from 0 to 0.62 with increasing residence time. The particle size increased with increasingresidence time, and no significant difference in divalent cations was observed. The Me/Fe molar ratio in theobtained solid-solution nanoparticles of MeFe2O4 and -Fe2O3 increased with increasing residence time andKOH molality. The Me/Fe molar ratio also increased in the order Zn < Cu < Ni at a given residence time,and this trend could be explained on the basis of ZnO, CuO, and NiO solubilities. The increase of the sizeand the Me/Fe molar ratio in the obtained particles with increasing residence time shows that, in the formationmechanism, primary solid-solution particles with low Me/Fe molar ratios probably nucleated and, after surfacedissolution of the particles, dissolved Fe3+ recrystallized on the surface with incorporation of Me2+.