Low‐temperature synthesis of uranium monocarbide by a Pechini‐type in situ polymerizable complex method
Low‐temperature synthesis of uranium monocarbide by a Pechini‐type in situ polymerizable complex method
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DOI：
10.1111/jace.15438
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发表时间：
2018-07
影响因子：
3.9
通讯作者：
Hangxu Guo;Jieru Wang;J. Bai;S. Cao;Denglei Chen;Yalou Sun;Xiaojie Yin;Wei Tian;Cunmin Tan;Qing Huang;Zhi Qin;Q. Deng
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文献类型：
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作者：
Hangxu Guo;Jieru Wang;J. Bai;S. Cao;Denglei Chen;Yalou Sun;Xiaojie Yin;Wei Tian;Cunmin Tan;Qing Huang;Zhi Qin;Q. Deng
以有机物为唯一碳源，采用Pechini型原位可聚合络合物技术（IPC）成功合成了碳化铀（UC）。在水性方法中，柠檬酸（CA）和甘露醇的混合物聚合以形成海绵状有机聚合物前体而没有任何沉淀。采用XRD、DSC‐TG、SEM（EDX）、TEM和FT‐IR等手段研究了前驱体的结构演变和形成机理。XRD结果表明，在1400°C的低温下，当n（甘露醇）/n（CA）= 1.0/0.3/1.0时，可得到UC。SEM和TEM分析表明，UO 2纳米颗粒均匀分布在碳基体中，形成UO 2/C纳米复合材料，亚微米尺寸的椭球形UC颗粒相互胶结在一起。FT-IR表明，首次得到了一种-CA螯合结构，实现了铀和C的分子级混合。原位炭化保证了UO 2与C的紧密接触，使碳热还原反应温度较低，扩散距离较短。
Uranium monocarbide (UC) was successfully synthesized by the Pechini‐type in situ polymerizable complex technique (IPC) with the organic matter as the only carbon source. In the aqueous process, a mixture of citric acid (CA) and mannitol with was polymerized to form a spongy‐like organic polymeric precursor without any precipitations. The structural evolution and formation mechanism of the precursor were investigated using XRD, DSC‐TG, SEM (EDX), TEM, and FT‐IR. XRD results demonstrated that UC was obtained with the /mannitol/CA molar ratios of 1.0/0.3/1.0 at a low temperature of 1400°C. SEM and TEM analyses revealed that the UO2nanoparticles were uniformly distributed in the carbon matrix to form UO2/C nanocomposites, and submicrometer‐sized ellipsoidal UC particles cemented together. FT‐IR showed that a ‐CA chelated structure was firstly obtained, achieving the molecular scale mixing of uranium and C. Then the in situ charring guaranteed the intimate contact of UO2and C, leading to a low reaction temperature in carbothermal reduction owing to a short diffusion distance.