Photo-induced low temperature synthesis of nanocrystalline UO2, ThO2 and mixed UO2–ThO2 oxides

Photochemically induced preparation of nanocrystalline uranium and/or thorium oxides is based on UV radiation induced formation of amorphous solid precursor in aqueous solutions containing uranium and/or thorium nitrate and ammonium formate. Subsequent heat treatment under various atmospheres leads to formation of nanocrystalline UO2, ThO2 or UO2–ThO2 solid solution at minimum temperatures in the interval 300–550 °C. The materials consist of nanoparticles from 3 to 15 nm in diameter and with narrow size distribution.