The missing pieces of the PuO₂nanoparticle puzzle

Abstract

<p>We report a full characterization of PuO₂ nanoparticles at the atomic level and probe their local and electronic structure by a variety of methods available at the synchrotron and theoretical approaches.</p>

The Application of HEXS and HERFD XANES for Accurate Structural Characterisation of Actinide Nanomaterials: The Case of ThO2

“…The effects of the initial chemical conditions, polymerisation of the initial Th IV precipitates and the stability of the NPs overt ime can be addressedw ith this methodology.T he latter is of particular interest because ThO 2 NPs, in contrast to NPs of other actinided ioxides synthesised by the same chemistry route, show an increase in size and crystallinity over time (ageing effect) depending on the conditions. Our findings on ThO 2 ,i nc omparison with recentr esults on CeO 2 [65] and PuO 2 [15,16] NPs synthesised under similarc onditions, show differences in systems that are often indicated as very similar. The fact that thorium haso nly one oxidation state, unlike cerium andp lutonium, prevents the accommodation of chargei mbalancew ith oxidation or reduction at selected sites.…”

“…One of the most investigated topics of radiochemistry at the nanoscale is the formationo ft etravalent actinideo xide NPs in aqueous solution. [7][8][9][12][13][14][15][16][17] Tracking their aggregation mechanism under different chemical conditions, identifying the presence of multiple oxidation states and characterising their surfaces are real challenges. Even what is considered the simplest system,T hO 2 ,f or which only the tetravalent oxidation state is stable, is hotly debated.…”

“…One of the most investigated topics of radiochemistry at the nanoscale is the formation of tetravalent actinide oxide NPs in aqueous solution [7–9, 12–17] . Tracking their aggregation mechanism under different chemical conditions, identifying the presence of multiple oxidation states and characterising their surfaces are real challenges.…”

Insight into the structure–property relationship of UO2nanoparticles

“…9,10,46,[66][67][68][69] The HERFD method at the An M 4 edge probes An 3d-5f electronic transitions and is thus highly effective for the detection of the 5f electron configuration and for oxidation state identification. 9,10,39,40,46,66 Moreover, the shapes of the recorded data on various mixed uranium oxides are so distinct 66,67 that recorded HERFD spectra on uranium systems can be straightforwardly analyzed by a fingerprint approach to detect the presence of U 4 O 9 /U 3 O 8 impurities in UO 2 NPs. Fig.…”

Speciation of Uranium and Plutonium From Nuclear Legacy Sites to the Environment: A Mini Review

“…Recently, it was found that Pu(IV) stabilization onto mineral surfaces may result in Pu surface precipitation in the form of PuO 2 nanoparticles (Kirsch et al, 2011 ; Romanchuk et al, 2013 , 2016a ; Schmidt et al, 2013 ; Zhao et al, 2016 ) ( Figure 2 ). Therefore, the study of PuO 2 nanoparticles becomes increasingly important, and it is actively being conducted (Powell et al, 2011 ; Romanchuk et al, 2018 ; Kvashnina et al, 2019 ; Gerber et al, 2020 ).…”