Ammonia-Gas-Sensing Characteristics of WO3/Carbon Nanotubes Nanocomposites: Effect of Nanotube Content and Sensing Mechanism

作者:Nguyen Van Duy; Nguyen Duc Hoa*; Nguyen Thanh Dat; Dang Thi Thanh Le; Nguyen Van Hieu*
来源:Science of Advanced Materials, 2016, 8(3): 524-533.
DOI:10.1166/sam.2016.2716

摘要

Gas sensors based on the nanocomposite of nanostructured tungsten oxide (WO3) and carbon nanotubes (CNTs) were fabricated for ammonia (NH3) detection. The nanostructured WO3 material was fabricated using a hydrothermal method, whereas the nanocomposites were prepared by mixing WO3 powders with CNTs. Morphology and quality of the synthesized materials were characterized by X-ray diffraction, Raman spectroscopy, and scanning electron microscopy analyses. Effects of CNT content on the NH3 sensing characteristics of nanocomposites were systematically investigated. Results demonstrated that the fabricated gas sensors enabled NH3 monitoring with fast response and recovery times of few seconds, which are suitable for actual application in environmental monitoring. A gas-sensing mechanism of the WO3/CNT composites was proposed based on the formation of a Schottky heterojunction between CNT and WO3.