A facile additive-free method for tunable fabrication of UO2 and U3O8 nanoparticles in aqueous solution

Spherical UO2 nanoparticles with an average diameter varying from 30 to 250 nm and U3O8 nanocuboids with a width of 400 nm and a length of 1 μm have been successfully synthesized just by a simply additive-free hydrothermal synthesis method. To selectively obtain the phase-pure U3O8 and UO2 nanoparticles, the experimental conditions, such as the solution pH and temperature as well as the concentration of hydrazine, have been established and optimized. The products were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). In order to investigate the growth mechanism of the uranium oxide nanoparticles, XRD, SEM and Fourier transform infrared (FT-IR) spectrum measurements were carried out for the precursors prepared at different pH and hydrothermal time. The crucial factor for tunable fabrication of uranium oxide nanoparticles could come from the different reducing ability of hydrazine at various solution pH.