纳米Fe_2O_3的制备及其对高氯酸铵热分解的催化性能  

Preparation of Nanometer-Sized Fe_2O_3 and Its Catalytic Performance for Ammonium Perchlorate Decomposition

作　　者：马振叶[1] 李凤生[1] 崔平[1] 白华萍[1] 

机构地区：[1]南京理工大学国家特种超细粉体工程技术研究中心,江苏南京210094

出　　处：《催化学报》2003年第10期795-798,共4页

基　　金：中国人民解放军总装备部预研项目 (4 13 2 80 3 0 5 0 7)

摘　　要：用两相体系方法制备了纳米Fe2 O3 ,并用X射线衍射、红外光谱和粒度分析对其结构进行了表征 .结果表明 ,当有机溶胶的 pH =6 ,油酸与Fe3 +的摩尔比为 1∶3 5时 ,Fe(OH) 3 在油相中的萃取率可高达 90 % ,将有机溶胶在 12 0℃回流 8h后可得到非晶态、窄粒度分布的纳米Fe2 O3 粒子 ,其粒径在 12nm左右 .分别采用恒容燃烧热和差热分析研究了纳米Fe2 O3 对高氯酸铵热分解的催化性能 .结果表明 ,在模拟固体推进剂中分别加入 4 7%微米Fe2 O3 和 4 7%纳米Fe2 O3 后 ,恒容燃烧热分别提高了 2 35 0 84和 5 0 95 70J/g.在高氯酸铵中加入 5 %微米Fe2 O3 可使高氯酸铵两个放热峰的出现分别提前 1 10和6 2 2 5℃ ,而加入 5 %纳米Fe2 O3 时分别提前 6 1 89和 118 82℃ ,这说明纳米Fe2 O3 的催化活性优于微米Fe2 O3 .There is a great deal of interest in using nanometer sized ferric oxide as catalyst in the solid propellant. The problem is that nanoparticles of ferric oxide prepared by the traditional method are easy to aggregate in water phase and cannot be distributed homogeneously in the solid propellant, which leads to a decrease in the catalytic activity. To solve the problem, nanoparticles of ferric oxide are prepared in an oil water two phase system in this paper. XRD, FT IR spectroscopy and particle size analysis are used to characterize their microstructure. The results show that the rate of Fe(OH) 3 extraction from the water phase to the oil phase is near 90% at pH=6 and an oleic acid to Fe 3+ molar ratio of 1/3 5. After refluxing the organic sol at 120 ℃ for 8 h, the amorphous nanoparticles with a narrow size distribution (12 nm) are obtained. The heat of constant volume combustion of the simulating solid propellant with 4 7% micrometer sized ferric oxide increases by 2?350 84 J/g , while the heat of constant volume combustion of the propellant with 4 7% nanometer sized ferric oxide increases by 5?095 70 J/g . Thermal analysis shows that the two exothermic peaks of ammonium perchlorate with micrometer sized ferric oxide shift to temperatures 1 10 and 62 25 ℃ lower than those of pure ammonium perchlorate, respectively, while the temperatures of the two peaks of ammonium perchlorate with nanometer sized ferric oxide decrease by 61 89 and 118 82 ℃, respectively, which means that the catalytic performance of nanometer sized Fe 2O 3 is superior to that of micrometer sized Fe 2O 3. With increasing content of nanometer sized ferric oxide, the temperature of the second exothermic peak of ammonium perchlorate decreases more. The temperature of the first exothermic peak of ammonium perchlorate does not change too much when the content of nanometer sized ferric oxide is 1% and 2 5%, but it decreases significantly when the content is up to 5%.

关 键 词：两相体系 氧化铁 纳米粒子 高氯酸铵 热分解 

分 类 号：O643.3[理学—物理化学]