Highly crystalline UO2 nanoparticles (NPs) with sizes of 2-3 nm were produced by fast chemical deposition of uranium(IV) under reducing conditions at pH 8-11. The particles were then characterized by microscopic and spectroscopic techniques including high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), high-energy resolution fluorescence detection (HERFD) X-ray absorption spectroscopy at the U M4 edge and extended X-ray absorption fine structure (EXAFS) spectroscopy at the U L3 edge. The results of this investigation show that despite U(IV) being the dominant oxidation state of the freshly prepared UO2 NPs, they oxidize to U4O9 with time and under the X-ray beam, indicating the high reactivity of U(IV) under these conditions. Moreover, it was found that the oxidation process of NPs is accompanied by their growth in size to 6 nm. We highlight here the major differences and similarities of the UO2 NPs properties with PuO2, ThO2 and CeO2 NPs.
@article{arxiv.2102.11643,
title = {Insight into the structure-property relation of UO2 nanoparticles},
author = {Evgeny Gerber and Anna Yu. Romanchuk and Stephan Weiss and Stephen Bauters and Bianca Schacherl and Tonya Vitova and René Hübner and Salim Shams Aldin Azzam and Dirk Detollenaere and Dipanjan Banerjee and Sergei M. Butorin and Stepan N. Kalmykov and Kristina O. Kvashnina},
journal= {arXiv preprint arXiv:2102.11643},
year = {2021}
}