纳米Co_3O_4的制备及其对高氯酸铵热分解的催化性能

Preparation of Nanocrystalline Co_3O_4 and Its Catalytic Performance for Thermal Decomposition of Ammonium Perchlorate

选用CoCl2.6H2O分别与NaOH,H2C2O4.2H2O,Na2CO3.10H2O及Na2C2O4组成四个反应体系,通过室温固相反应制备了不同平均粒径的纳米Co3O4,并用X射线衍射和透射电镜对Co3O4的物相、形貌和粒径大小进行了表征.结果表明,Co3O4的平均粒径分别为23,30,35和150 nm,大小均匀,分散性好.还用差热分析法考察了纳米Co3O4对高氯酸铵热分解的催化性能,并与微米Co3O4进行了比较.结果表明,纳米Co3O4可使高氯酸铵的低温放热峰消失,高温放热峰温度降至323.5℃,降低了128.5℃,表观分解热增加了750 J/g,达1 265 J/g,纳米Co3O4对高氯酸铵热分解的催化性能明显好于微米Co3O4.

The Co3O4 nanopowder with different average crystallite size was prepared via room-temperature solid phase reaction of CoCl2· 6H2O with NaOH, H2C2O4· 2H2O, Na2CO3· 10H2O and Na2C2O4, respectively. The phase, morphology and particle size of the Co3O4 samples were characterized by X-ray diffraction and transmission electron microscopy. The results showed that the Co3O4 powders were 23, 30, 35 and 150 nm, respectively, in average crystallite size, uniform, and well-dispersed. The catalytic performance of the nano-sized Co3O4 for the decomposition of ammonium perchlorate was investigated by differential thermal analysis in comparison with micron-sized Co3O4. The results indicated that the nano-sized Co3O4 made the temperature of the lower- temperature exothermic peak of ammonium perchlorate disappear, the temperature of the higher-temperature exothermic peak of ammonium perchlorate decrease by 128.5 ℃ and the apparent decomposition heat increase from 515 to 1 265 J/g. The nano-sized Co3O4 showed better catalytic performance for the thermal decomposition of ammonium perchlorate than the micron-sized Co3O4.