Reduction behavior of neptunium(V) at a gold or platinum electrode during controlled potential electrolysis and procedures for electrochemical preparations of neptunium(IV) and (III)

Autor: Sorin Kihara, Takaumi Kimura, Yoshihiro Kitatsuji
Rok vydání: 2010
Předmět:
Zdroj: Journal of Electroanalytical Chemistry. 641:83-89
ISSN: 1572-6657
DOI: 10.1016/j.jelechem.2009.12.015
Popis: Unique current–time relations were observed during the controlled potential electrolysis for the reduction of NpO 2 + to Np4+ or Np3+ at a gold or platinum electrode in perchloric acid solution. The reduction process of NpO 2 + was elucidated based on controlled potential electrolysis and voltammetry as follows: Though NpO 2 + is not reduced directly at a gold electrode, it is reduced by chemical reaction with Np3+ which is produced by the electrode reduction of Np4+. Here, Np4+ is initially produced through the disproportionation of NpO 2 + , and generated progressively through the reduction of NpO 2 + . The reduction of NpO 2 + at a platinum electrode is initiated by the electrocatalytic reduction to Np4+ with the hydrogen atom which is produced by the electrode reduction of H+ and adsorbed on the platinum electrode surface. The Np4+ produced functions as an electron transfer mediator to reduce NpO 2 + similar to the reaction at a gold electrode. The above described catalytic reduction processes of NpO 2 + were elucidated with the aid of digital simulation of bulk electrolyses. Methods useful for the preparation of Np4+ and Np3+ by bulk electrolysis were proposed based on the experimental results.
Databáze: OpenAIRE
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