Effects of different phases of MnO2 nanorods on the catalytic thermal decomposition of ammonium perchlorate

Different crystallographic forms of MnO2 nanorods (α, β, γ, and mixed phase) were prepared using a hydrothermal method with different reaction times or reagents. The samples obtained were characterized by X-ray diffractometry and transmission electron microscopy. The catalytic activities of the different phases of MnO2 nanorods during thermal decomposition of ammonium perchlorate (AP) were investigated using thermogravimetric analysis. The catalytic activity of MnO2 was mainly size-related and not phase-controlled. Different phases of MnO2 with similar average diameters showed similar catalytic activities and differed from the other catalytic activities of different crystallographic forms of MnO2. Mixed-phase MnO2, which presented the smallest average diameter of 9.5 nm, showed the best catalytic activity and lowered the AP peak temperature by 132.4 °C.