Low-temperature hydrothermal synthesis of WO 3 nanorods and their sensing properties for NO 2

Shouli Bai, Kewei Zhang, Ruixian Luo, Dianqing Li, Aifan Chen, Chung Chiun Liu

研究成果: 雜誌貢獻期刊論文同行評審

210 引文 斯高帕斯(Scopus)

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.

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頁(從 - 到)12643-12650
頁數8
期刊Journal of Materials Chemistry
22
發行號25
DOIs
出版狀態已出版 - 7 7月 2012

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