Synthesis and characterization of Ln2O2SO4 (Ln = Gd, Ho, Dy and Lu) nanoparticles obtained by coprecipitation method and study of their reduction reaction under H2 flow

We have proposed an optimized homogeneous precipitation method for the synthesis of spherical and well-dispersed pure Ln 2 O 2 SO 4 (Ln = Gd, Ho, Dy and Lu) nanoparticles (NPs) using synthesized lanthanide sulfates and urea as starting materials. Ln 2 O 2 SO 4 NPs can be easily transformed to Ln 2 O 2 S by reduction under H 2 flow at 650 °C for Gd, Dy and Ho whereas the reduction with Lu gave only Lu 2 O 3 . Particle size was between 500 nm and 3.5 µm. This reduction method allows to obtain Ln 2 O 2 S without using H 2 S which is highly toxic and uncomfortable gas. Ln 2 O 2 SO 4 /Ln 2 O 2 S synthetized can be used for release and oxygen storage or doped with luminescent centers for multimodal medical imaging applications. Graphical abstract