Facile synthetic route to hollow gadolinium oxide spheres with tunable thickness

Uniform rare-earth gadolinium oxide (Gd₂O₃) hollow spheres with tunable shell thickness have been successfully fabricated in the presence of SiO₂ as templates via a urea-based homogeneous precipitation method. The synthesis is a mild, low-cost and convenient method without any catalysts. By varying the times of the precipitation procedure, the shell thickness can be successfully controlled within the 20-55-nm range. The thickness increase of each coating might be -10-nm. The as-synthesised product was identified from X-ray diffraction pattern, scanning electron microscopy and energy dispersive X-ray. The prepared hollow Gd₂O₃ spheres with tunable shell thickness and fluorescence property have the potential to be used for drug delivery, fluorescent labelling and controlled release applications.