Self-assembled 3D La(OH)3 and La2O3 nanostructures: Fast microwave synthesis and characterization

Self-assembled three-dimensional (3D) urchin-like and flower-like La(OH)₃ nanostructures were successfully prepared for the first time via a facile and fast microwave-assisted solution-phase chemical method in 15 min. The obtained products were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The SEM results reveal that the urchin-like and flower-like La(OH)₃ nanostructures are ca. 3 μm and 6 μm in diameter, respectively. The urchin-like La(OH)₃ nanostructures are constructed by nanorods with diameters of about 300 nm and lengths of about 500 nm. The flower-like La(OH)₃ nanostructures are built from nanopetals about 100 nm thick. The effects of reaction time, microwave power, amount of tetraethyl ammonium bromide (TEAB), and surfactants on the preparation were systematically investigated. The possible formation mechanism of the 3D La(OH)₃ nanostructures was preliminarily discussed. Urchin-like and flower-like La₂O₃ nanostructures were obtained after calcining the La(OH)₃ nanostructures at 800 °C for 4 h. Urchin-like and flower-like La₂O₃:Eu³⁺ nanostructures were also prepared and their photoluminescence (PL) properties were investigated.