Ice on U-Pu Oxide Films
European Commission, Joint Research Centre (JRC), 2023
Online
unknown
Zugriff:
The surface reduction of films of the mixed oxide of uranium U−Pu−O2 with adsorbed water ice was studied by ultraviolet and X-ray photoelectron spectroscopy (UPS and XPS, respectively). The films were produced as thin films by reactive sputter deposition. Water was condensed as a thick ice overlayer on the surface at low temperature. Subsequent warming led to desorption of the ice. When warmed up under ultraviolet light (UV light, HeI and HeII radiation), the surface was reduced. In thhe uranium−plutonium mixed oxide (U−Pu MOX), plutonium was reduced from plutonium dioxide (PuO2) to plutonium sesquioxide (Pu2O3). Uranium reduction seems to be activated. Surface reduction is explained as a photocatalytic reaction of the surface, triggered by the excitation of electrons from the valence (or impurity) band into the conduction band. The enhancement of reactivity of the mixed oxide compared to pure uranium is explained by the higher band gap of plutonium dioxide (PuO2) compared to uranium dioxide (UO2).The machine used for this study was the hot machine.
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Ice on U-Pu Oxide Films
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Veröffentlichung: | European Commission, Joint Research Centre (JRC), 2023 |
Medientyp: | unknown |
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