Starch-Assisted Gel-Combustion Synthesis of Nano α-Fe2O3 and Its Catalytic Effect on Ammonium Nitrate Decomposition

Abstract

Nano-sized α-Fe₂O₃ powders were synthesized via a starch-assisted gel-combustion method. The effects of fuel type, equivalence ratio (Φ), and ammonium nitrate addition on phase formation and crystallite size were systematically investigated by X-ray diffraction. Among the examined fuels, starch promoted the formation of well-crystallized α-Fe₂O₃ under optimized combustion conditions. The crystallite size could be effectively tuned by adjusting Φ and ammonium nitrate content, yielding nanoparticles with an average size of approximately 26 nm under optimal conditions. Morphological analysis confirmed the formation of nanoscale particles with partial agglomeration, and the specific surface area of the optimized sample reached 76.28 m²/g, as determined by BET analysis. The catalytic performance of the synthesized α-Fe₂O₃ nanoparticles toward ammonium nitrate decomposition was evaluated using differential thermal analysis. A significant reduction in decomposition peak temperature was observed with increasing catalyst loading. Kissinger kinetic analysis revealed a pronounced decrease in activation energy compared to pure ammonium nitrate, demonstrating the enhanced catalytic activity of the prepared nanoparticles. The results indicate that starch-assisted gel-combustion synthesis provides an effective route for producing catalytically active nano α-Fe₂O₃ powders.