Synthesis of NiO-SnO ₂ cauliflower-like gas sensor material using a facile hydrothermal method for acetone detection

Abstract The present study has successfully synthesized a cauliflower-like hierarchy microstructure of NiO-SnO 2 through a facile and cost-effective hydrothermal method for acetone detection. S2 sensor, containing 0.25 mole% Ni, exhibited great performance in acetone gas sensing, with a response of 1734 at 1000 ppm at 350 °C, two times more than pristine SnO 2 . At lower concentrations, the responses were recorded to be 325, 170, 70, and 35 for 200 ppm, 100 ppm, 50 ppm, and 20 ppm of acetone balanced in nitrogen, respectively. Moreover, at the optimal operating temperature, 350 °C, swift response and recovery times of 8 s and 2 min 18 s were recorded when exposed to 20 ppm of acetone balanced in nitrogen, respectively. Also, the sensor was further assessed for its ability to distinguish acetone from other gases by exposing it to equal concentrations of 200 ppm of acetone, carbon dioxide, ammonia, and ethanol, all balanced in nitrogen, and tested at 350 °C. The sensor showed 142.74-, 143.39-, and 2.42-times higher responses in acetone than carbon dioxide, ammonia, and ethanol, respectively, indicating outstanding selectivity for detecting acetone. Lastly, the sensor showed remarkable operational stability when tested over repeated exposure cycles of acetone gas.