Aloe vera leaf extract-assisted facile green synthesis of amorphous Fe2O3 for catalytic thermal decomposition of ammonium perchlorate

Abstract

Fe2O3 is a well-known catalyst for thermal decomposition of ammonium perchlorate (AP). Amorphous Fe2O3 nanoflakes were biosynthesised by a novel sol–gel method using Aloe vera leaf extract, and its catalytic effect on thermal decomposition of AP was investigated. The precursor ferric nitrate–Aloe vera gel was calcined at three different temperatures. The oxides were characterised by Fourier-transform infrared spectroscopy, X-ray powder diffraction, atomic force microscopy, field emission scanning electron microscopy and transmission electron microscopy. Microscopy analyses revealed that Fe2O3-250 consists of a porous structure as aggregates of many nanoflakes of ~ 2 nm diameter. The catalytic activity of the synthesised products on thermal decomposition of AP was evaluated using thermogravimetry–differential scanning calorimetry. The presence of 2.0% of mesoporous Fe2O3-250 catalyst (surface area of 208 m2 g−1) enhanced the rate of high-temperature decomposition of AP by decreasing the peak decomposition temperature from 367 to 337 °C. Average activation energy of thermal decomposition of AP was calculated using Flynn–Wall–Ozawa method reduced from 145 to 128 kJ mol−1 in the presence of the catalyst. The high surface area of mesoporous Fe2O3-250 originated from its amorphous nature makes it a potential catalyst for thermal decomposition of AP.