直形碳纳米管、分叉碳纳米管负载纳米NiO及其对高氯酸铵热分解的影响

采用射流进样催化裂解法制备了直形碳纳米管(CNTs)、分叉碳纳米管, 分别以二者为载体, 用化学沉积法制备了负载纳米NiO的复合粒子, 并研究了纳米NiO和CNTs的单一纳米粒子、简单混合物、复合物对高氯酸铵(AP)热分解的催化性能, 对催化效果的差异作了初步探讨. 结果表明: NiO/直形CNTs和NiO/分叉CNTs复合粒子比表面积大, 表面负载层的纳米NiO结晶好、粒子均匀、粒径小、分散性好. 复合粒子对AP热分解的催化效果比单一纳米粒子和简单混合物好, 其中NiO/分叉CNTs复合粒子催化效果最好, 使AP高温分解峰温降低了94.6 ℃, 使表观分解热增加了819 J/g. CNTs的载体支撑作用, 可防止NiO纳米粒子的团聚, 增大比表面积, 增加反应活性中心, 增加催化效果, 载体分叉CNTs的枝杈形结构, 有利于纳米NiO/分叉CNTs复合粒子催化性能的提高.

Nano-NiO/straight-CNTs and Nano-NiO/branched-CNTs Composites and Their Effects on the Thermal Decomposition of Ammonium Perchlorate

Straight and branched carbon nanotubes (CNTs) were synthesized by catalytic chemical pyrolysis through jet sample introduction. And using them as carriers, different nano-NiO/CNTs composites were prepared by chemical precipitation. Further research on the catalysis of the thermal decomposition of ammonium perchlorate (AP) by single particles, combined particles and composite particles was carried out and the difference of the catalysis was also discussed. The results show that the straight-CNTs with good morphology, lesser defects and better degree of graphitization and the branched-CNTs with high contents of branched structures, more defects and worse degree of graphitization could be controlled by the experimental conditions. The synthesized NiO/CNTs composites with good crystallinity, uniform coats and large surface area had good catalysis on the thermal decomposition of AP. Between the two composites, the catalysis by NiO/branched-CNTs was better and they decreased the high temperature decomposition peak of AP by 94.6 ℃ and increased the apparent heat of decomposition of AP by 819 J•g^－1, respectively. The supporting effect of the CNTs could effectively prevent the aggregation of particles, and increase the specific surface area and the active sites. The branch structure of CNTs was propitious to improve the catalysis of the NiO/branched-CNTs composites.