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Title: Electrochemistry and Spectroelectrochemistry of the Pu (III/IV) and (IV/VI) Couples in Nitric Acid Systems

Authors:
 [1];  [1];  [1];  [1];  [1];  [1]
  1. Nuclear Chemistry and Engineering, Pacific Northwest National Laboratory, Richland WA 99352
Publication Date:
Sponsoring Org.:
USDOE Office of Nuclear Energy (NE)
OSTI Identifier:
1393275
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Electroanalysis
Additional Journal Information:
Related Information: CHORUS Timestamp: 2017-09-20 08:23:33; Journal ID: ISSN 1040-0397
Publisher:
Wiley Blackwell (John Wiley & Sons)
Country of Publication:
Germany
Language:
English

Citation Formats

Lines, Amanda M., Adami, Susan R., Casella, Amanda J., Sinkov, Sergey I., Lumetta, Gregg J., and Bryan, Samual A. Electrochemistry and Spectroelectrochemistry of the Pu (III/IV) and (IV/VI) Couples in Nitric Acid Systems. Germany: N. p., 2017. Web. doi:10.1002/elan.201700465.
Lines, Amanda M., Adami, Susan R., Casella, Amanda J., Sinkov, Sergey I., Lumetta, Gregg J., & Bryan, Samual A. Electrochemistry and Spectroelectrochemistry of the Pu (III/IV) and (IV/VI) Couples in Nitric Acid Systems. Germany. doi:10.1002/elan.201700465.
Lines, Amanda M., Adami, Susan R., Casella, Amanda J., Sinkov, Sergey I., Lumetta, Gregg J., and Bryan, Samual A. 2017. "Electrochemistry and Spectroelectrochemistry of the Pu (III/IV) and (IV/VI) Couples in Nitric Acid Systems". Germany. doi:10.1002/elan.201700465.
@article{osti_1393275,
title = {Electrochemistry and Spectroelectrochemistry of the Pu (III/IV) and (IV/VI) Couples in Nitric Acid Systems},
author = {Lines, Amanda M. and Adami, Susan R. and Casella, Amanda J. and Sinkov, Sergey I. and Lumetta, Gregg J. and Bryan, Samual A.},
abstractNote = {},
doi = {10.1002/elan.201700465},
journal = {Electroanalysis},
number = ,
volume = ,
place = {Germany},
year = 2017,
month = 9
}

Journal Article:
Free Publicly Available Full Text
This content will become publicly available on September 20, 2018
Publisher's Accepted Manuscript

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  • The solution chemistry of Pu in nitric acid is explored via electrochemistry and spectroelectrochemistry. By utilizing and comparing these techniques, an improved understanding of Pu behavior and its dependence on nitric acid concentration can be achieved. Here the Pu (III/IV) couple is characterized using cyclic voltammetry, square wave voltammetry, and a spectroelectrochemical Nernst step. Results indicate the formal reduction potential of the couple shifts negative with increasing acid concentration and reversible electrochemistry is no longer attainable above 6 M HNO3. Spectroelectrochemistry is also used to explore the irreversible oxidation of Pu(IV) to Pu(VI) and shine light on the mechanism andmore » acid dependence of the redox reaction.« less
  • The Pt(II) complexes [Pt(bpy)(py)[sub 2]][sup 2+] (I), [Pt(bpy)(Me[sub 2]N-py)[sub 2]][sup 2+] (II), [Pt(Me[sub 2]-bpy)(py)[sub 2]][sup 2+] (III), [Pt(bpy)(en)][sup 2+] (IV), [Pt(Mebpy-H)(py)[sub 2]][sup 2+] (V), [Pt(Mebpy-H)(bpy)][sup 2+] (VI), [Pt(phen)(py)[sub 2]][sup 2+] (VII), and [Pt(py)[sub 4]][sup 2+] (VIII) (bpy, 2,2[prime]-bipyridine; py, pyridine; Mebpy-H, N-methyl-2,2[prime]-bipyridinyl-C(3),N[prime]; Me[sub 2]-bpy, 4,4[prime]-dimethyl-2,2[prime]-bipyridine; Me[sub 2]N-py, 4-(dimethylamino)pyridine; en, 1,2-diaminoethane; phen, 1,10-phenanthroline) have been investigated by cyclic voltammetry and where possible by EPR spectroelectrochemistry and by UV-vis-near-IR spectroelectrochemistry. All complexes except VIII show at least two reversible reductive one-electron processes; VI shows three, and VIII shows one chemically irreversible process. In all cases, the doubly reduced species showed the characteristicmore » [pi][sup *] [yields] [pi][sup *] UV-vis-near-IR absorptions of the ligand anion radicals. For the singly reduced species, EPR spectra show the added electron to be localized on the bipyridine-type ligand. However, the UV-vis-near-IR spectra of these species are not typical of ligand-based reduction products, and the potentials are less negative than expected for such a process. The authors conclude that the singly reduced species are best formulated as containing Pt(II), with the semioccupied and/or the lowest unoccupied ligand orbitals (corresponding to the LUMO and SLUMO of the unreduced parent species) being perturbed by the presence of metal orbitals. The doubly reduced species, however, are straightforward anion radical complexes of Pt(I).« less
  • The electrochemical and spectroelectrochemical behavior of Europium(III) chloride in a molten salt eutectic, 3 LiCl – 2 KCl, over a temperature range of 643 – 1123 K using differential pulse voltammetry, cyclic voltammetry, potential step chronoabsorptometry, and thin-layer spectroelectrochemistry is reported. The electrochemical reaction was determined to be the one electron reduction of Eu3+ to Eu2+ at all temperatures. The redox potential of Eu3+/2+ shifts to more positive potentials and the diffusion coefficient for Eu3+ increases as temperature increases. The results for the number of electrons transferred, redox potential and diffusion coefficient are in good agreement between the electrochemical andmore » spectroelectrochemical techniques.« less
  • Fast, cost effective, and robust means of detecting and quantifying lanthanides are needed for supporting more efficient tracking within the nuclear, medicinal, and industrial fields. Spectroelectrochemistry (SEC) is a powerful technique combining electrochemistry and spectroscopy that can meet those needs. The primary limitation of SEC as a detection method for lanthanides is their low molar absorptivity in absorbance based measurements and low emission intensities in fluorescence based measurements; both lead to high limits of detection. These limitations can be circumvented by complexing the lanthanides with sensitizing ligands that enhance fluorescence, thereby dropping the limits of detection. Complexation may also stabilizemore » the metal ions in solution and improve the electrochemical reversibility, or Nernstian behavior, of the redox couples. To demonstrate this concept, studies were completed using europium in complexes with four different sensitizing ligands. Initial work indicates Eu in the four complexes studied does display the necessary characteristics for SEC analysis, which was successfully and reproducibly applied to all Eu complexes.« less