AUTHOR=Zhu Ziyan , Ly Malin , Liu Nazhen , Noël James J. , Shoesmith David W. 

TITLE=The kinetics of hydrogen peroxide reduction on rare earth doped UO2 and SIMFUEL

JOURNAL=Frontiers in Materials

VOLUME=9

YEAR=2022

URL=https://www.frontiersin.org/journals/materials/articles/10.3389/fmats.2022.1038310

DOI=10.3389/fmats.2022.1038310

ISSN=2296-8016

ABSTRACT=<p>The electrochemical reduction of hydrogen peroxide has been studied in sodium chloride solutions containing various anions (bicarbonate/carbonate, sulphate) on Gd-UO<sub>2</sub>, Dy-UO<sub>2</sub> and a SIMFUEL (UO<sub>2</sub> doped to simulate spent nuclear fuel). The reaction was observed to proceed <italic>via</italic> the chemical oxidation of the surface to produce U<sup>V</sup> followed by its subsequent electrochemical reduction. The reaction was faster on the SIMFUEL surface due to the availability of the oxygen vacancies required to incorporate the O<sup>II</sup> ions necessary to maintain charge balance. Bicarbonate/carbonate, but not sulphate, was found to suppress peroxide reduction. This could be caused either by peroxide decomposition in solution or by the catalysis of peroxide reformation <italic>via</italic> the reaction of surface hydroxyl radicals with bicarbonate/carbonate to form carbonate radicals which subsequently decompose by reaction with water. The noble metal particles present in the SIMFUEL appear to play only a minor role in the reduction process.</p>