Green synthesis of perovskite-type FeMnO₃ nanoparticles: Study of its electrochemical hydrogen storage and catalytic activity on the thermal decomposition of ammonium perchlorate

Perovskite-based mixed metal oxides have become a promising material as efficient catalysts and electrocatalysts for various energy storage-related and fuel applications in modern scientific society. This study is the first attempt to explore the catalyst and electrocatalyst application of iron manganese oxide (FeMnO₃) perovskite. The pure FeMnO₃ nanoparticles (NPs) were synthesized using a green method by Aloe vera extract as a capping agent. The cubic crystal structure, nanosized particle, purity, mesoporous feature and ferromagnetic properties of FeMnO₃ NPs were confirmed using XRD, FT-IR, FESEM-EDS mapping, BET, and VSM analysis. The electrocatalyst properties of the sample were measured using cyclic voltammetry (CV), chronopotentiometry (CP), and electrochemical impedance spectroscopy (EIS) techniques. The results showed that the specific capacitance value and hydrogen storage capacity of FeMnO₃ NPs were about 382.5 Fg⁻¹ and 2622 mAhg⁻¹ in the aqueous alkaline medium (3 M KOH), respectively. Additionally, the catalytic activity of the sample on the thermal decomposition of ammonium perchlorate (AP) was analyzed using differential scanning calorimetry (DSC) and thermogravimetry (TGA) instruments. The results revealed that FeMnO₃ NPs enhanced the released heat of AP from 525 to 1760 Jg⁻¹ and reduced the decomposition temperature from 458 to 381 °C.