Effect of ferrous/ferric ions molar ratio on reaction mechanism for hydrothermal synthesis of magnetite nanoparticles

Bulletin of materials science

H Tanaka¹  T Kawai¹  N Mizutani²  T Iwasaki²  S Watano²  T Yanagida¹ 

[1]Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan$$Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, JapanInstitute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan$$

[2]Department of Chemical Engineering, Osaka Prefecture University, 1-1 Gakuen-cho, Nakaku, Sakai, Osaka 599-8531, Japan$$Department of Chemical Engineering, Osaka Prefecture University, 1-1 Gakuen-cho, Nakaku, Sakai, Osaka 599-8531, JapanDepartment of Chemical Engineering, Osaka Prefecture University, 1-1 Gakuen-cho, Nakaku, Sakai, Osaka 599-8531, Japan$$

关键词: Fe3O4 nanoparticles;    particle size;    crystallinity;    magnetic property;    Schikorr reaction.;   

DOI  :  

学科分类：材料工程

来源: Indian Academy of Sciences

【 摘 要 】

Magnetite nanoparticles were prepared by hydrothermal synthesis under various initial ferrous/ferric molar ratios without adding any oxidizing and reducing agents in order to clarify effects of the molar ratio on the reaction mechanism for the formation of magnetite nanoparticles. The magnetite nanoparticles prepared were characterized by a scanning electron microscope, powder X-ray diffractometer, and superconducting quantum interference device (SQUID). At the molar ratio corresponding to the stoichiometric ratio in the synthesis reaction of magnetite from ferrous hydroxide and goethite, the nucleation of magnetite crystals progressed rapidly in an initial stage of the hydrothermal synthesis, resulting in formation of the magnetite nanoparticles having a smaller size and a lower crystallinity. On the other hand, at higher molar ratios, the particle size and crystallinity increased with increasing molar ratio because using surplus ferrous hydroxide the crystallites of magnetite nanoparticles grew up slowly under hydrothermal conditions according to the Schikorr reaction. The magnetite nanoparticles prepared under various molar ratios had good magnetic properties regardless of the molar ratio.

【 授权许可】

Unknown