Hydrothermal synthesis of monostructured LaPO4: morphology and structure

The application field of materials based on lanthanum orthophosphate (LaPO4) including nanomaterials, has been permanently extending recently. The high level of mechanical properties and the compatibility with numerous oxides make it possible to consider the possibility of using lanthanum orthophosphate as a composite material for construction purposes. This application is particularly promising when nanoparticles with quasi-1D morphology (nanorods) are used. The high isomorphic capacity of the LaPO4-based phase for alkaline-earth ions and ions of lanthanides and actinides, high chemical stability, and high radiation hardness make promising the application of this compound as a matrix for immobilization of radioactive wastes. The possibility of obtaining lanthanum phosphate (LaPO4) by the hydrothermal method is considered in the work. Effects of pH, temperature and time of processing of hydrothermal synthesis on the morphology and structure of monostructured lanthanum phosphate are studied. It has been established that, with the increase of pH, the morphology of phosphate changed, the size of the crystallites increased, while the crystal structure changed from hexagonal to monoclinic.