Carbon-Doped WO3 Nanostructure Based on CNT Sacrificial Template and its Application to Highly Sensitive NO2 Sensor

• Published in: IEEE sensors journal Vol. 20; no. 11; pp. 5705 - 5711
• Main Authors: Kang, Yunsung, Baek, Dae-Hyun, Pyo, Soonjae, Kim, Jongbaeg
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.06.2020; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Annealing; Carbon; Carbon doping; carbon nanotube; Carbon nanotubes; Doping; Fabrication; gas sensor; Nanostructure; Nitrogen dioxide; Operating temperature; Photoelectrons; Porosity; Room temperature; sacrificial template; Sensors; Spectrum analysis; Surface area; Surface treatment; Synthesis; Temperature sensors; Tungsten; tungsten oxide; Tungsten oxides; X-ray spectroscopy
• ISSN: 1530-437X; 1558-1748
• DOI: 10.1109/JSEN.2020.2973347

This paper first reports a technique for the fabrication of carbon (C)-doped tungsten oxide (WO 3 ) nanostructures using a carbon nanotube (CNT) sacrificial template and demonstrates its application to a highly sensitive NO 2 sensor. All fabrication steps are scalable, and the C-doped WO 3 synthesis and CNT removal are conducted simultaneously using a single annealing procedure. The prepared nanostructures are analyzed based on scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and energy-dispersive X-ray spectroscopy. These analysis methods confirm that the CNT template is completely removed and that the carbon is doped into the synthesized WO 3 nanostructures during a single annealing process. The synthesized C-doped WO 3 nanostructures exhibit high porosity and a large surface area of which CNT template originally have, which is a highly advantageous aspect to sensitive gas detection. In addition, carbon doping into WO 3 is effective at lowering the optimal operating temperature. The developed sensor can sensitively detect various NO 2 concentrations from 8 down to 0.5 ppm at room temperature, which is attributed to the carbon-doping effect and large surface area of the synthesized nanostructures.