Preparation and Catalytic Application of the Cobalt-containing Nanoscale Mixed Metal Oxides
ABSTRACT
The cobalt-containing nanoscale mixed metal oxides were prepared and their catalytic behavior on thermal decomposition of Ammonium Perchlorate (AP) was investigated. Co/Ni/Fe nanoscale mixed metal oxides were obtained by calcination of Co/Ni/Fe hydrotalcites precursors. X-ray powder diffraction (XRD), thermo gravimetric analysis (TGA) and transmission electron microscopy (TEM) were used to characterize their structure and morphology, and their catalytic behaviors on thermal decomposition of AP were investigated by differential scanning analysis (DSC) and TGA.
The XRD, TGA and TEM results showed that Co/Ni/Fe hydrotalcite precursor have regular structures in high dispersion. The thermal decomposition of hydrotalcite precursor were finished under 500℃ and Co/Ni/Fe nanoscale mixed metal oxides were obtained at the same time. Co/Ni/Fe mixed metal oxides showed CoFe2O4 and NiFe2O4 structure; all samples showed regular structures in high dispersion with diameters of 30-40nm. The DSC and DTA results showed that high decomposition temperature of AP were shift more or less to lower temperature by the catalysis of Co/Ni/Fe nanoscale mixed metal oxides, and the low temperature decomposition peak were disappeared which meant that AP decomposed directly after crystal transfer. While the crystal transfer temperature were not affected by mixed metal oxides. The most significant result was that the Co5Ni1Fe3 mixed metal oxide calcined at 500 ℃ which made the high temperature decomposition of AP shift to 315.7 ℃，about which decreased 103.14 ℃. With the increase of Co content, Co/Ni/Fe catalysts made decomposition temperature of AP decreased. With the increase of calcination temperature, the high temperature decomposition of AP tend to moving to high temperature, the catalyst calcined by 400-500 ℃ are best in catalytic behavior, while the increase dosage of catalysts could improve the catalytic behavior of the mixed metal oxides.
In this thesis, an effective and feasible way has been provided to improve the solid propellant burning rate. The AP decomposition temperature could be significantly decreased by cobalt-containing nanoscale mixed metal oxides, which could improve the combustion behavior of solid propellant in further.
