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.

Key words: straight-CNTs, branched-CNTs, NiO, composite particle, ammonium perchlorate, catalysis