WO 3 hydrothermal synthesis for NO gas sensor

Abstract In this study, NO gas sensors based on hydrothermally synthesized tungsten oxide (WO 3 ) nanomaterials were successfully fabricated and characterized. Specifically, by systematically varying the hydrothermal synthesis time at 4, 8, 12, and 16 h, we investigated the effects of synthesis time on the morphology and structure of the WO 3 nanomaterials and their NO gas sensing performance. The NO gas sensing performance of the WO 3 sensor was highest at the optimal operating temperature of 150 °C. The optimized WO 3 sensor exhibited a peak response of 67.96 towards 10 ppm NO gas. Furthermore, the optimized WO 3 sensor demonstrated a low limit of detection of approximately 0.04 ppm for NO gas, and stable repeatability over 40 repeated cycles. The sensor exhibited selectivity toward NO compared to ethanol, hydrogen, and carbon oxide, which was clearly validated using principal component analysis. These findings propose that morphology-controlled WO 3 is a promising material for NO detection applications.