作　　者： (刘舒婷）; (苏涛）; (张鹏）; (费泽杰）; (刘洪涛）;

机构地区： 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

摘　　要： 本实验研制了高温原位紫外-可见吸收光谱仪，并结合标准的电子顺磁共振谱仪来研究HTS（53wt％KNO3—40wt％NaNO2-7wt％NaNO3）熔盐分解过程中是否产生超氧离子．实验结果表明NaNO2相对于NaNO3更易于产生超氧负离子，并且熔盐中的超氧负离子在420~440nm有吸收峰，在HTS熔盐中该吸收峰随温度升高发生红移．这个吸收峰可归属为NaO2或KO2电荷转移跃迁，该跃迁将会导致分解后熔盐显黄色．同时实验还获取了高温熔融态的NaNO2和NaNO3紫外可见吸收光谱，并在文中与HTS结果进行详细对比和讨论． 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： 超氧负离子 熔盐分解 高温原位紫外 可见吸收光谱 电子顺磁共振谱