化工毕业论文 含Co纳米复合金属氧化物的制备及催化性能研究.doc

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,℃,比纯AP(℃)℃。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 position 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 position 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 position 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 position temperature of AP were shift more or less to lower temperature