CTAB-assisted hydrothermal synthesis of Ba2SnO4 nanostructures for enhanced NO2 gas sensing performance

In this study, Ba₂SnO₄ nanostructures were successfully synthesized via the hydrothermal method and employed for gas sensing applications. Two samples were prepared with and without the use of a surfactant in order to investigate its influence on the structural, morphological, optical characteristics and gas sensing performance of Ba₂SnO₄ nanostructures. The obtained powders were processed into thick films using the screen-printing technique. Comprehensive characterization was carried out using X-ray diffraction (XRD), UV–Visible spectroscopy, scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM–EDS), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric /differential thermal analysis (TGA/DTA), Raman spectroscopy, and electrical measurements. The gas sensing performance of the synthesized Ba₂SnO₄ thick films was evaluated toward NO₂, NH₃, LPG, H₂S, ethanol, and methanol gases. Among them, NO₂ exhibited the highest response. Sample S1 showed a maximum sensitivity of 68.74% at 160 °C for 1000 ppm NO₂, whereas Sample S2 demonstrated enhanced performance with 82.13% sensitivity at a lower temperature of 120 °C and 600 ppm NO₂ concentration. The limits of detection (LOD) were determined to be 152.97 ppm for S1 and 705.72 ppm for S2, respectively. Both samples displayed fast response and recovery times, along with good selectivity, stability, and reusability, confirming the potential of Ba₂SnO₄ thick films particularly the CTAB-assisted sample as promising candidates for efficient NO₂ gas sensors.