Size and shape evolution of magnetite nanocrystals in water-soluble system

By using a facile water-soluble system, we have selectively synthesized magnetite nanocrystals with sizes ranging from 15 to 300 nm, and with controllably variable morphologies including nanosphere, nanooctahedron and nanoprism. The synthesis strategy relies on the hydrothermal route of easily obtained FeSO₄ in a water-soluble system, whose solvent is mainly composed of ethylene glycol (E.G.) and de-ionized water (D. I. water), with ammonium hydroxide or urea as an additive. The shape and size of the final products were found to be strongly affected by reaction condition such as reaction time, the concentration of reactants and solvents and alkalinity. The nanocrystals obtained contain the prominent exposure of different crystallographic facets for the spinel magnetite, indicating their great applicable potentials in biotechnology, selective catalysis and ferrofluids. .