Electrochemical preparation and characterization of brain-like nanostructures of Y2O3

Nanostructured Y2O3 was successfully prepared via a two-step and template-free method. Firstly, yttrium hydroxide precursor was galvanostatically grown on the steel substrate from chloride bath by direct and pulse current deposition modes. Direct current deposition was carried out at the constant current density of 0.1 A/dm2 for 600 s. The pulse current was also performed at a typical on-time and off-time (ton=1 s and toff=1 s) with an average current density of 0.05 A/dm2 (Ia=0.05 A/dm2) for 600 s. The obtained hydroxide films were then scraped from the substrates and thermally converted into final oxide product via heat-treatment. Thermal behaviors and phase transformations during the heat treatment of the hydroxide powder samples were investigated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The final oxide products were characterized by means of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The results showed that the well-crystallized Y2O3 with brain- and sphere-like morphology were achievable via pulse and direct deposition modes, respectively. It was concluded that pulse current cathodic electrodeposition offered a facile route for preparation of nanostructured Y2O3.