Facile shape and size-controlled growth of uniform magnetite and hematite nanocrystals with tunable properties

Abstract

Monodispersed magnetite Fe 3 O 4 and hematite -Fe 2 O 3 nanocrystals have been grown in co-solvents of alcohol and water. Either the shape or the size of the nanocrystals could be easily controlled. Both the phases and nanostructures have been characterized by powder X-ray diffraction patterns and electron microscopy. The magnetic and catalytic properties of these products were investigated and compared with each other. The obtained results clearly demonstrate that these iron oxide nanocrystals are soft ferromagnetic at room temperature and -Fe 2 O 3 has a more effective catalytic property on the thermal decomposition of ammonium perchlorate than Fe 3 O 4 . Based on the experimental data, it is proposed that the magnetic and catalytic properties of these nanocrystals are dependent not only on the size and shape, but also on the surface structure of the nanocrystals. The nanoplates with significant anisotropic nanostructure demonstrate a highly enhanced performance as compared to nanoparticles. iron oxide, nanocrystals, growth, properties

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