Thermal Behavior and Thermolysis Mechanisms of Ammonium Perchlorate under the Effects of Graphene Oxide-Doped Complexes of Triaminoguanidine

Several transition metal complexes of triaminoguanidine (TAG) nitrate, TAG-Ni, TAG-Co, graphene oxide (GO)/TAG-Ni (GT-Ni), GO/TAG-Co (GT-Co), and GO/ TAG-Cu (GT-Cu) were prepared using GO as a stabilizer. It has been shown that these complexes are promising energetic catalysts for decomposition of ammonium perchlorate (AP), which was uniformly coated with the mentioned catalysts. The decomposition kinetic parameters and mechanisms of the complexes have been studied by means of differential scanning calorimetry/thermogravimetric techniques. Results show that the presence of GO in such hybrid catalysts is able to stabilize AP before its decomposition, but the strong catalytic effects occur on HClO₄ as the intermediate of the initial decomposition of AP. In the cases of TAG-Co, GT-Co, and GT-Cu, they would make the two-step decomposition of AP into a single step. The heat releases have been greatly increased as well because of a more complete decomposition. More importantly, the thermolysis mechanism of AP could be changed by simply modifying the type of metal ions. Under the effect of these catalysts, the decomposition more or less shifts to two-dimensional growth of the nuclei model, which indicates that the metal ions played key roles as active centers. The decomposition usually starts from the surface of AP, where the contact of the catalysts further enhanced the surface reactions. The inclusion of GO on the surface of the AP crystal may hinder the evaporation of NH₃, and therefore the mechanism has been changed to the phase boundary-controlled reaction.