Abstract
Aqueous solutions of lithium uranyl triperoxide, Li4[UO2(O2)3] (LiUT), were irradiated with gamma rays at room temperature and found to form the uranyl peroxide cage cluster, Li24[(UO2)(O2)(OH)]24 (Li-U24). Raman spectroscopy and 18O labeling were used to identify the Raman-active vibrations of LiUT. With these assignments, the concentration of LiUT was tracked as a function of radiation dose. A discrepancy between monomer removal and cluster formation suggests that the reaction proceeds by the assembly of an intermediate. Non-negative matrix factorization was used to separate Raman spectra into components and resulted in the identification of a unique intermediate species. Much of the conversion appears to be driven by water radiolysis products, particularly the hydroxyl radical. This differs from the 18O-labeled copper-catalyzed formation of U24, which progresses at a steady rate with no observation of intermediates. Li-U24 in solution decomposes at high radiation doses resulting in a solid insoluble product similar to Na-compreignacite, Na2(UO2)6O4(OH)6·7H2O, which contains uranyl oxyhydroxy sheets.
| Original language | English |
|---|---|
| Pages (from-to) | 11916-11922 |
| Number of pages | 7 |
| Journal | Inorganic Chemistry |
| Volume | 61 |
| Issue number | 30 |
| DOIs | |
| State | Published - Aug 1 2022 |
| Externally published | Yes |
Funding
This research was supported by the Department of Energy, National Nuclear Security Administration, under Award Number DE-NA0003763 until December 2020, and by University funds. The authors acknowledge the Center for Sustainable Energy at Notre Dame (ND Energy) Materials Characterization Facility for the use of the Bruker D8 ADVANCE Davinci powder X-ray diffractometer. The authors thank Prof. Michael Wiescher for making available the facilities of the Notre Dame Nuclear Science Laboratory, which is supported by the U.S. National Science Foundation through Grant Phys-0758100, and Prof. Ian Carmichael for making available the facilities of the Notre Dame Radiation Laboratory, which is supported by DOE BES through the Grant DE-FC02-04ER15533. This contribution is NDRL-5352 from the Notre Dame Radiation Laboratory.