铀氧化物的氧化还原行为及其价态的X—射线光电子能谱的研究

应用Ｘ－射线光电子能谱对铀氧化物（ＵＯ２、ＵＯ３、Ｕ３Ｏ８）的化学态及其不同价态的相对含量（Ｕ＾４＋／Ｕ＾６＋）进行了研究，结果表明，常温下ＵＯ２在空气中可氧化形成ＵＯ２＋ｘ；ＵＯ３易与水结合形成水合物，在高温和高真空中易脱氧，部分Ｕ＾６＋转变成Ｕ＾４＋；Ｕ３Ｏ８中存在Ｕ＾４＋和Ｕ＾６＋两种价态，其相对量之比为１∶２。铀氧化物中Ｕ＾４＋和Ｕ＾６＋的Ｕ４ｆ７／２结合能相差１ｅＶ左右，借助于曲线拟合技

Study of Redox Behaviour of Uranium Oxides and Their Valence State Ratio by X-Ray Photoelectron Spectrometry

The redox behaviour of uranium oxides (UO2,UO3,U3O8) and their valence state ratios (U4+/U6+)have been studied by XPS. The results indicate that UO2can be oxidized into UO2+x, in air at ambient temperature; UO3 combines with H2O to form hydrous oxide easily , and a fraction of hexavalent uranium on the surface can change into quadrivalent due to its deoxidation in high vacuum chamber at high temperature; U3O8 consists of two kinds of different valence states of uranium oxides, i. e. U4+and U6+,and the relative intensity ratio between them is 1 : 2. Although binding energy difference between U4+and U8+4f7/2 peaks of uranium oxides is about 0. 9-1. 2 eV ,quantitative analysis of relative content of different valence state of uranium can be carried out in terms of the curve fitting technique by computer.