Hydrothermal Synthesis and Gas Sensing Performance of Spinel-type SnFe2O4 Nanomaterials: Influence of Synthesis Condition

Gas sensors play a crucial role in ensuring safety across environmental, industrial, and healthcare sectors, thereby driving demand for cost-effective materials with high sensing performance. In this study, spinel-type SnFe₂O₄ nanomaterials were successfully synthesized via a hydrothermal method at different temperatures (180 °C, 200 °C, and 220 °C), followed by calcination at 500 °C, to investigate the effects of synthesis conditions on their microstructural characteristics and gas sensing behavior. X-ray diffraction (XRD) analysis confirmed the formation of single-phase spinel SnFe₂O₄ with high crystallinity, while SEM images revealed a clear evolution of morphology from irregular agglomerates at 180 °C to uniform spherical nanoparticles at 200 °C, and well-defined cubic structures at 220 °C. Gas sensors fabricated from these nanomaterials exhibited high sensitivity and stable performance toward the target gases, demonstrating the potential of SnFe₂O₄ for practical sensing applications. The results highlight the critical role of hydrothermal temperature in tailoring particle morphology and optimizing the functional properties of SnFe₂O₄. These findings suggest that SnFe₂O₄ is a promising candidate for next-generation gas sensors, particularly in industrial monitoring and environmental protection.