摘要
The hexagonal （h）-WO3-Cr2o3 nanocomposites with different W/Cr molar ratio of 4：1,10：1 and 40：1 were prepared by a facile two-step hydrothermal method, and its gas sensing properties were investigated under optimum working temperature. X-ray diffraction （XRD）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, high resolution transmission electron microscopy （HRTEM） were used to characterize the morphology, microstructure and crystallinity of the as-synthesized samples. The hexagonal WO3 nanorods show a better crystallinity than Cr2O3 nanoparticles. When the molar ratio of W/Cr is 10：1, the hexagonal WO3-Cr2O3 nanocomposite shows obvious selectivity toward 2-butanone at 205℃ compared with other typical reducing gases, and the response value to 100 ppm 2- butanone can reach 5.6. However, there is no selectivity toward 2-butanone when the Cr/W molar ratio is 1：4 and 1：40. Furthermore, hexagonal WO3-Cr2O3 nanocomposites have a short response and recovery time to 5ppm 2-butanone, which is lOs and 80s, respectively. The measured results indicate that hexagonal WO3-Cr2O3 nanocomposite is a potential gas sensing material for monitoring volatile organic compounds （VOCs）.
The hexagonal （h）-WO3-Cr2o3 nanocomposites with different W/Cr molar ratio of 4：1,10：1 and 40：1 were prepared by a facile two-step hydrothermal method, and its gas sensing properties were investigated under optimum working temperature. X-ray diffraction （XRD）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, high resolution transmission electron microscopy （HRTEM） were used to characterize the morphology, microstructure and crystallinity of the as-synthesized samples. The hexagonal WO3 nanorods show a better crystallinity than Cr2O3 nanoparticles. When the molar ratio of W/Cr is 10：1, the hexagonal WO3-Cr2O3 nanocomposite shows obvious selectivity toward 2-butanone at 205℃ compared with other typical reducing gases, and the response value to 100 ppm 2- butanone can reach 5.6. However, there is no selectivity toward 2-butanone when the Cr/W molar ratio is 1：4 and 1：40. Furthermore, hexagonal WO3-Cr2O3 nanocomposites have a short response and recovery time to 5ppm 2-butanone, which is lOs and 80s, respectively. The measured results indicate that hexagonal WO3-Cr2O3 nanocomposite is a potential gas sensing material for monitoring volatile organic compounds （VOCs）.
基金
supported by the National Natural Science Foundation of China(Nos. 21303118, 51573137)
the Doctor Projectfor Young Teachers of Ministry of Education(No. 20130032120003)
the Seed Foundation of Tianjin University(No. 1501)
