Controllable synthesis of multi-shelled NiCo 2 O 4 hollow spheres catalytically for the thermal decomposition of ammonium perchlorate.

The compatible catalytic structure of NiCo 2 O 4 was modified into multi-shelled hollow spheres by one-pot synthesis, followed by heat treatment. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Brunauer-Emmet-Teller (BET) and N 2 adsorption-desorption approaches were used for the characterizations of nanoparticles and multi-shelled hollow porous structures and the morphologies and crystal structures of these hollow spheres, respectively. Differential scanning calorimetry (DSC) was adopted for comparing the thermal decomposition performances of ammonium perchlorate (AP) catalyzed by adding different contents of multi-shelled NiCo 2 O 4 hollow spheres. Impressively, the experimental results showed that the NiCo 2 O 4 hollow spheres exhibited more excellent catalytic activity than NiCo 2 O 4 nanoparticles as a result of their large specific surface areas, good adsorption capacity and many active reduction sites. The decomposition temperature of AP with multi-shelled NiCo 2 O 4 hollow spheres could be reduced up to 322.3 °C from 416.3 °C. Furthermore, a catalytic mechanism was proposed for the thermal decomposition of AP over multi-shelled NiCo 2 O 4 hollow spheres based on electron transfer processes.