Identification of Superoxide O2^- during KNO3-NaNO2-NaNO3 Salt by Electron UV-Vis Absorption Spectroscopy Thermal Decomposition of Molten Paramagnetic Resonance and  

利用电子顺磁共振和紫外／可见吸收光谱研究熔融KNO3-NaNO2-NaNO3盐分解过程中的超氧负离子

作　　者：刘舒婷[1] 苏涛[1] 张鹏[1] 费泽杰 刘洪涛[1] 

机构地区：[1]中国科学院上海应用物理研究所,熔盐化学与工程技术部,上海201800

出　　处：《Chinese Journal of Chemical Physics》2017年第4期372-378,I0001,共8页化学物理学报（英文）

基　　金：This work was supported by the ＂Strategic Priority Research Program, TMSR＂ of the Chinese Academy of Sciences （No.XD02002400）, the National Natural Science Foundation of China （No.51506214）, the Hundred Talents Program, CAS and Shanghai Pujiang Program.

摘　　要：On account of excellent thermal physical properties, molten nitrates/nitrites salt has been widely employed in heat transfer and thermal storage industry, especially in concentrated solar power system. The thermal stability study of molten nitrate/nitrite salt is of great importance for this system, and the decomposition mechanism is the most complicated part of it. The oxide species O2^2- and O2^- were considered as intermediates in molten KNO3-NaNO3 while hard to been detected in high temperature molten salt due to their trace concentration and low stability. In this work, the homemade in situ high temperature UV- Vis instrument and a commercial electron paramagnetic resonance were utilized to supply evidence for the formation of superoxide during a slow decomposition process of heat transfer salt （HTS, 53 wt% KNO3/40 wt% NaNO2/7 wt% NaNO3）. It is found that the superoxide is more easily generated from molten NaNO2 compared to NaNO3, and it has an absorption band at 420-440 nm in HTS which red shifts as temperature increases. The band is assigned to charge-transfer transition in NaO2 or KO2, responsible for the yellow color of the molten nitrate/nitrite salt. Furthermore, the UV absorption bands of molten NaNO2 and NANO3 are also obtained and compared with that of HTS.

关 键 词：Superoxide Decomposition of heat transfer salt High temperature UV-visible Electron paramagnetic resonance 

分 类 号：O[理学]