Insight into the structure–property relationship of UO₂nanoparticles

Abstract

We show that the structural and electronic properties of UO2 NPs (2–3 nm) are similar to those of bulk UO2 under inert conditions, with U(iv) as the dominating oxidation state, though NPs oxidize with time and under the X-ray beam.

High-energy resolution X-ray spectroscopy at actinide M4,5 and ligand K edges: what we know, what we want to know, and what we can know

“…It was shown that the PuO 2 NPs remain intact after several months 63 with respect to the size (~2nm) and oxidation state 63 . Contrary to that, the UO 2 NPs increase in size up to ~6nm and become partially oxidized with time even if the samples were kept under inert conditions 66 . It was found that the U(V) signal increased and a conversion to the U 4 O 9 phase took place.…”

“…The actinide M 4,5 HERFD-XANES method gives the opportunity to fingerprint the oxidation state of the actinidecontaining materials. The first U M 4 experiment has been done on the mixed uranium oxides 3 , which was followed by several other Please do not adjust margins Please do not adjust margins studies on the chemical state verification in actinide systems 3,6,9,12,[60][61][62][63][64][65][66][67][68][69][70][71][72][73][74][75][76][77] . Fig.…”

“…The identification of the oxidation states by HERFD has become important for many areas of actinide science since it provides information on how electrons are distributed between elements. The oxidation-reduction (redox) reactions involve the transfer of electrons between chemical species 3,60,63,66,68,69,72,76,77,79 . Many biological processes rely on the electron transfer.…”

“…This has led to the new knowledge concerning the formation of the Pu-containing NPs in aqueous solutions that are extremely important for the performance assessment of geological repositories of the spent fuel and radioactive waste as well as for the effective remediation of contaminated sites. Later, the highly crystalline UO 2 NPs with the size of 2-3nm were studied by means of U M 4 HERFD 66 . Results also confirm that U(IV) is the dominant oxidation state.…”

X-ray absorption spectra of f-element complexes: insight from relativistic multiconfigurational wavefunction theory

“…[46][47][48][49][50][51] XANES at the metal L and M edges is also used in Ln and An chemistry research. 26,36,[52][53][54][55][56][57][58][59][60][61][62][63][64][65] The L edge probes dipole-allowed 2p → nd transitions and also provides information about the fshell occupation. The (relative) intensity between the spectral features, and the energy of the main edge, are very sensitive to the metal oxidation state and f-electron count.…”