【摘要】 采用改良的St觟ber法制备粒径约为200 nm的单分散球形SiO2颗粒,以此为内核,分别通过液相沉淀法和尿素均匀沉淀法制备包覆形式不同的新型SiO2/Co3O4核壳式纳米催化剂。采用X-射线衍射分析(XRD)、透射电子显微镜(TEM)、红外光谱分析(IR)、拉曼光谱分析(Raman)、BET比表面积测试等手段对产物进行表征,利用差式扫描量热仪(DSC)考察SiO2/Co3O4复合物对高氯酸铵(AP)热分解反应的催化作用,探讨不同包覆形式对其催化活性的影响。结果表明,两种方法制备得到的SiO2/Co3O4复合物分别为层包覆和粒子包覆,比表面积大,具有明显的核壳结构,且粒子包覆形式的SiO2/Co3O4对AP热分解反应的催化效果最好,使AP的高温分解温度降低了110℃,放热量增加了662 J·g-1。更多还原

【Abstract】 Highly dispersed SiO2 microspheres with mean diameter of 200 nm were prepared by modified Stber method. Then the prepared SiO2 nanoparticles were coated with Co3 O4 via liquid precipitation method and urea homogeneous precipitation method respectively, thus a new type SiO2 /Co3 O4 core-shell catalysts with different coating forms were obtained. X-ray diffraction(XRD), transmission electron microscopy(TEM), infrared(IR) spectra, Raman Microscopy and BET specific surface area measurement were used to characterize the SiO2 /Co3 O4 composite nanoparticles. The catalytic activities of SiO2 /Co3 O4 composites for thermal decomposition of ammonium perchlorate(AP) were studied by differential scanning calorimetry(DSC). Furthermore, we espescially investigated the influence of different coating forms on its catalytic effect. The results indicate that SiO2 /Co3 O4 nanocomposites synthesised by different methods possess obvious core-shell structure are with high specific surface area,which are layer-coated and particle-coated respectively. And the catalytic activity of particle-coated SiO2 /Co3 O4 nanocomposites is best, which reduce the high decomposition temperature of AP by 110 ℃, and increase heat quantity by 662 J·g-1.更多还原