摘要： Tungsten trioxide (WO 3 ) nanorods with an aspect ratio of ∼50 have been successfully synthesized by hydrothermal reaction at a low temperature of 100 °C. The crystal structure, morphology evolution and thermal stability of the products are characterized in detail by XRD, FESEM, FTIR, and TG/DTA techniques. The diameter evolution and distribution of WO 3 nanorods strongly depend on hydrothermal temperature and time. Hydrothermal conditions of 100 °C and 24 h ensure the formation of well-defined WO 3 nanorods. The transition of the crystal structure from monoclinic WO 3 to hexagonal WO 3 occurs after calcination at 400 °C. The appropriate calcination conditions of the WO 3 nanorods are defined to be 600 °C and 4 h for gas-sensing applications. Response measurements reveal that the WO 3 sensor operating at 200 °C exhibits high sensitivity to ppm-level NO 2 and small cross-sensing to CO and CH 4 , which makes this kind of sensor a competitive candidate for NO 2 -sensing applications. Moreover, impedance measurements indicate that a conductivity mechanism of the sensor is mainly dependent on the grain boundaries of WO 3 nanorods. A possible adsorption and reaction model is proposed to illustrate the gas-sensing mechanism. WO 3 nanorods, with an aspect ratio of ∼50, exhibit high sensitivity to ppm-level NO 2 without interference from CO and CH 4 . 出版日期： 2012-06-06 資源來源： Alma/SFX Local Collection 識別號： ISSN: 0959-9428 識別號： EISSN: 1364-5501 識別號： DOI: 10.1039/c2jm30997a
