Electroreduction Mechanism of UO 2 Cl 2 and Nucleation and Morphology of Uranium Dioxide at Different Conditions

作者：Yixuan Cai, Mei Li, Rugeng Liu, Meng Zhang, Wei Han · 发表于：Inorganic Chemistry · 年份：2025 · DOI：10.1021/acs.inorgchem.5c01019 · 被引用次数：6 · 研究领域：Radioactive element chemistry and processing、Molten salt chemistry and electrochemical processes、Electrochemical Analysis and Applications

To investigate the electroreduction mechanism of UO 2 Cl 2 and the nucleation mode and morphology of uranium dioxide, the electrochemical behavior of UO 2 2+ on the tungsten (W) electrode was studied in LiCl–KCl molten salt by cyclic voltammetry. The results demonstrated that UO 2 2+ underwent two sequential single-electron transfers to form UO 2 . Prior to its reduction to UO 2 +, UO 2 2+ was initially converted into a low-coordination complex ion. Besides the reduction peak of bulk UO 2, a peak associated with the strong adsorption of UO 2 on the electrode surface was also observed. The nucleation mode of UO 2 was examined by chronoamperometry, revealing that the nucleation mechanism was related to UO 2 Cl 2 concentration. The influence of current densities on nucleation morphology was studied using an atomic force microscope and found the nuclei was smaller and denser at higher current density. The deposits obtained by galvanostatic electrolysis at different current densities were examined by scanning electron microscopy–energy-dispersive X-ray spectroscopy and X-ray diffraction, showing that a regular octahedral UO 2 was formed at low current density, while a dendritic UO 2 was formed at high current density. A two-step electrolysis with an initial high current density followed by a low current density was conducted, and a dense UO 2 with a lychee-like morphology was produced.