含Co纳米复合金属氧化物的制备及催化性能研究

论文编号:CL128  论文字数:19434,页数:36

 含Co纳米复合金属氧化物的制备及催化性能研究

摘  要
 本论文主要研究了含Co纳米复合金属氧化物的制备及其对高氯酸铵(AP)热分解的催化性能。以Co/Ni/Fe类水滑石为前驱体，经高温焙烧制得Co/Ni/Fe纳米复合金属氧化物，采用X射线粉末衍射(XRD)、热重分析(TGA)和透射电镜(TEM)对其结构、热稳定性及形貌进行了表征，并通过差示量热扫描分析(DSC)和TGA研究了含Co纳米复合金属氧化物对AP热分解的催化性能。
 XRD、TGA和TEM分析结果表明，Co/Ni/Fe三元类水滑石前驱体的结构完整，晶粒大小均匀，分散良好，在500℃时水滑石分解完成，得到Co/Ni/Fe三元纳米复合金属氧化物催化剂；Co/Ni/Fe三元纳米复合金属氧化物催化剂均具有CoFe2O4和NiFe2O4的结构，样品未发生团聚，分散性好，尺寸在30-40nm范围内，有效的解决了传统纳米催化剂易团聚的问题。DSC和TGA分析结果表明，Co/Ni/Fe纳米复合金属氧化物催化剂均可使AP的高温分解峰不同程度的向低温方向移动，部分样品可使AP的低温分解峰消失，即AP在完成由斜方晶系向立方晶系的晶型转变后，直接进入高温分解。其中，Co5Ni1Fe3水滑石500℃焙烧得到的催化剂效果最好，可使AP的高温分解峰移动至323.1℃，比纯AP（413.8℃）降低了90.7℃。随着Co含量的增加，Co/Ni/Fe纳米复合金属氧化物催化AP的高温分解温度呈逐渐降低趋势；随着焙烧温度的增加，AP高温分解峰基本趋于向高温方向移动的趋势，400-500℃焙烧得到的催化剂催化效果最理想；增加催化剂的添加量，可明显提高催化效果。
 本研究为改善固体推进剂的燃速提供了一条可行且有效的途径。含Co纳米金属复合氧化物的加入可以有效降低AP高温热分解的温度，从而进一步改善固体推进剂的燃烧性能。
 
关键词：高氯酸铵 热分解 催化性能 含Co复合金属氧化物 类水滑石
 
 
Preparation and Catalytic Application of the Cobalt-containing Nanoscale Mixed Metal Oxides
ABSTRACT

 The cobalt-containing nanoscale mixed metal oxides were prepared and their catalytic behavior on thermal decomposition of Ammonium Perchlorate (AP) was investigated. Co/Ni/Fe nanoscale mixed metal oxides were obtained by calcination of Co/Ni/Fe hydrotalcites precursors. X-ray powder diffraction (XRD), thermo gravimetric analysis (TGA) and transmission electron microscopy (TEM) were used to characterize their structure and morphology, and their catalytic behaviors on thermal decomposition of AP were investigated by differential scanning analysis (DSC) and TGA.
 The XRD, TGA and TEM results showed that Co/Ni/Fe hydrotalcite precursor have regular structures in high dispersion. The thermal decomposition of hydrotalcite precursor were finished under 500℃ and Co/Ni/Fe nanoscale mixed metal oxides were obtained at the same time. Co/Ni/Fe mixed metal oxides showed CoFe2O4 and NiFe2O4 structure; all samples showed regular structures in high dispersion with diameters of 30-40nm. The DSC and DTA results showed that high decomposition temperature of AP were shift more or less to lower temperature by the catalysis of Co/Ni/Fe nanoscale mixed metal oxides, and the low temperature decomposition peak were disappeared which meant that AP decomposed directly after crystal transfer. While the crystal transfer temperature were not affected by mixed metal oxides. The most significant result was that the Co5Ni1Fe3 mixed metal oxide calcined at 500 ℃ which made the high temperature decomposition of AP shift to 315.7 ℃，about which decreased 103.14 ℃. With the increase of Co content, Co/Ni/Fe catalysts made decomposition temperature of AP decreased. With the increase of calcination temperature, the high temperature decomposition of AP tend to moving to high temperature, the catalyst calcined by 400-500 ℃ are best in catalytic behavior, while the increase dosage of catalysts could improve the catalytic behavior of the mixed metal oxides.
 In this thesis, an effective and feasible way has been provided to improve the solid propellant burning rate. The AP decomposition temperature could be significantly decreased by cobalt-containing nanoscale mixed metal oxides, which could improve the combustion behavior of solid propellant in further.

Keywords: ammonium perchlorate thermal decomposition catalytic behavior cabalt-containing mixed metal oxide;  hydrotalcite-like compounds
 
 目  录
 摘  要 I
 ABSTRACT II
 1 绪论 6
 1.1 纳米材料简介 6
 1.1.1 纳米材料的性能 6
 1.1.2 纳米材料的制备方法 8
 1.2 以类水滑石为前驱体制备复合氧化物的研究现状 8
 1.2.1 水滑石的组成及结构特征 8
 1.2.2 类水滑石的制备方法 9
 1.2.3 类水滑石衍生的复合氧化物 10
 1.3 高氯酸铵（AP）及其热分解 11
 1.3.1 高氯酸铵 11
 1.3.2 高氯酸铵的热分解 11
 1.3.3 AP热分解反应的催化机理 12
 1.4 纳米催化剂及在推进剂中的应用研究 12
 1.4.1 复合推进剂的主要成分 12
 1.4.2 纳米催化剂在推进剂中的应用及进展 12
 1.5 本文研究的目的与内容 13
 2 Co/Ni/Fe三元类水滑石前驱体的制备及其表征 15
 2.1 引言 15
 2.2 实验部分 15
 2.2.1 Co/Ni/Fe三元类水滑石前驱体的制备 15
 2.3 结果与讨论 17
 2.3.1 Co/Ni/Fe三元类水滑石前驱体的XRD表征 17
 2.3.2 Co/Ni/Fe三元类水滑石前驱体的TGA分析 18
 2.3.3 Co/Ni/Fe三元类水滑石前驱体的TEM分析 19
 2.4 本章小结 20
 3 Co/Ni/Fe三元纳米复合金属氧化物的制备及其催化性能研究 21
 3.1 引言 21
 3.2 实验部分 21
 3.2.1 Co/Ni/Fe三元纳米复合金属氧化物的制备 21
 3.2.2 催化剂/AP复合样品的制备与性能表征 22
 3.3 结果与讨论 22
 3.3.1 Co/Ni/Fe三元纳米复合金属氧化物催化剂的表征 22
 3.3.2 纯AP的热分解 24
 3.3.3 Co/Ni/Fe三元复合金属氧化物对AP热分解的催化性能 26
 3.4本章小结 31
 4结论与展望 33
 4.1 结论 33
 4.2 展望 33
 参考文献 34
 谢  辞 36

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