Synthesis of rare earth hydroxide nanorods by room temperature reaction of oxide precursors with water

In this study, solid state chemical reaction of anhydrous chloride precursors with Na2CO3 has been used to manufacture composite powders of nanocrystalline rare earth oxide grains embedded within a matrix of NaCl. Subsequent washing of these powders with deionised water resulted in removal of the NaCl matrix and hydration of the oxide nanoparticles. In the case of Nd2O3 and Sm2O3, the hydration process yielded hydroxide nanorods. In contrast, washing of the Gd2O3 yielded a powder consisting of irregularly shaped nanoparticles of Gd2O3 and GdOOH. Analysis using high resolution transmission electron microscopy revealed that the Nd2O3 and Sm2O3 nanorods were not single crystals but were composed of crystalline subunits with a common $$ \left\langle {0001} \right\rangle $$ growth direction. The results obtained in this study demonstrate that rare earth hydroxide nanorods can be synthesised from oxide precursors without the need for hydrothermal processing at elevated temperature and pressure.