Speakers
Description
The detection and monitoring of hazardous gases, including hydrogen sulphide (H₂S), carbon monoxide (CO), nitrogen oxide (NO), sulphur dioxide (SO₂), carbon dioxide (CO₂), and liquefied petroleum gas (LPG), are essential for ensuring industrial safety and environmental health. In this study, highly sensitive and selective SnO₂ nanoparticle-based gas sensors were synthesised and characterised for multi-gas detection, with particular emphasis on H₂S. SnO₂ nanoparticles were synthesised via a hydrothermal method, with sodium hydroxide used to control the pH of the precursor solution. The structural, morphological, and optical properties were characterised using X-ray diffraction (XRD), scanning electron microscopy (SEM), and UV–Vis spectroscopy. The average crystallite sizes, estimated using Scherrer’s equation, ranged from 21 to 23 nm, in agreement with SEM observations. The optical band gap, determined from Tauc plots, varied between 3.71 eV and 3.87 eV. Gas sensing performance was evaluated using the Kinosistec system towards CO₂, SO₂, CO, LPG, NO, and H₂S target gases. Notably, the sensor based on nanostructures synthesised at pH 7.08 showed the highest response of 1,115,853 to 150 ppm H₂S, with response and recovery times of 9.94 minutes and 8.70 minutes, respectively. These results highlight the critical role of pH-controlled synthesis in enhancing SnO₂ sensor performance and demonstrate their potential for practical gas sensing applications.