Speaker
Description
Lanthanum- and samarium-based perovskites with the general formula ABO₃ were synthesized using the hydrothermal method. Structural characterization by X-ray diffraction (XRD) confirmed the formation of pure-phase LaFeO₃ and SmFeO₃, with crystallite sizes increasing from 10 nm to 19 nm. High-resolution transmission electron microscopy (HRTEM) further verified the perovskite structure, revealing a lattice spacing (d-spacing) of 0.232 nm. UV–Vis analysis indicated a slight increase in band gap energy for the samples. Scanning electron microscopy (SEM) images showed predominantly spherical nanoparticles. Gas sensing measurements demonstrated that the SmFeO₃-based sensor exhibited higher sensitivity toward volatile organic compounds (VOCs) compared to flammable gases. Additionally, the sensor showed good selectivity, repeatability, and stability. Notably, the SmFeO₃ sensor achieved a limit of detection (LoD) of approximately 2 ppm for NO₂ gas at an operating temperature of 125 °C.