High-performance methane gas sensor with low detection limit based on hydrothermally synthesized VO2 nanostructure
摘要
Due to the inherent flammability and explosion risk associated with methane (CH4), the development of gas sensors featuring high sensitivity, robust selectivity, and low-temperature operability remains a critical objective in safety-oriented sensing technologies. Among various detection strategies, metal oxide semiconductors (MOS) have gained considerable attention for CH4 sensing, owing to their thermal stability, cost-efficient synthesis, and high density of reactive surface sites. However, the practical deployment of MOS-based sensors has been hindered by performance limitations, particularly at lower temperatures. To overcome these challenges, this study employed vanadium dioxide (VO2) nanostructures synthesized via a hydrothermal approach. The resulting nanomaterials were characterized using comprehensive structural and morphological analysis techniques. Gas-sensing evaluations were conducted across a range of CH4 concentrations and operating temperatures (ambient to 50 °C), revealing enhanced response values and a reduced detection threshold at elevated temperatures. Specifically, the sensor exhibited response values of 5.8% at room temperature and 15.5% at 50 °C in the presence of 2000 ppm CH4. The detection limit was determined to be 1000 ppm at room temperature, improving to 100 ppm at 50 °C. Moreover, the sensor demonstrated excellent selectivity toward CH4, differentiating it from common interfering gases such as carbon monoxide (CO) and carbon dioxide (CO2). These findings establish VO2 nanostructures as viable candidates for integration into low-temperature methane sensing platforms in industrial and environmental settings.