Effect of ferric ions on the morphology and size of magnetite nanocrystals synthesized by ultrasonic irradiation

Two‐dimensional plate‐like Fe3O4 nanocrystals and nanoparticles could be synthesized by a simple one‐step sonochemical method through ultrasonic irradiation in reverse co‐precipitation solution at low temperature. This technique provided a facile and rapid way to prepare Fe3O4nanocrystals with different morphology and size. Magnetite nanoplates were synthesized with only ferrous salt adding into alkali solution, and adding ferric ions with low molar ratio in the metal salts solution would lead to the formation of very small magnetite nanoparticles (∼10 nm). The size of as‐prepared magnetite nanoparticles increased with increasing reaction temperature and showed narrow size distribution, the standard deviation less than 2 nm. This investigation indicated that ferric ions had significant influence on the morphology of Fe3O4 nanocrystals. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)