Investigation of catalytic activity of ZnAl2O4 and ZnMn2O4 nanoparticles in the thermal decomposition of ammonium perchlorate

ZnAl2O4 and ZnMn2O4 nanoparticles were synthesized by a modified co-precipitation method and characterized by means of Fourier transform infrared spectroscopy, X-ray diffraction, energy-dispersion X-ray spectrometer, and their morphology investigated by means of scanning electron microscopy. The effects of these nanoparticles on the thermal decomposition of ammonium perchlorate (AP) were examined by differential scanning calorimetery and thermogravimetery analyses. The results revealed that ZnAl2O4 nanoparticles have little catalytic effect on this process, but ZnMn2O4 nanoparticles have good catalytic effect on decreasing the decomposition temperature of AP and increasing the released heat. ZnAl2O4 and ZnMn2O4 nanoparticles increased the released heat of AP decomposition from 400 to about 736 and 1130 Jg(-1), respectively, and AP decomposition temperature decreased from 420 to 400 and 358 A degrees C in the same order. The higher catalytic activity of ZnMn2O4 can be due to its p-type semiconductivity and the presence of some positive hole and defects. Also, the kinetic parameters such as pre-exponential factor and activation energy were calculated using Kissinger method.