|
|||||
|
|
Preparation of hexagonal WO3 from hexagonal ammonium tungsten bronze for sensing NH3 |
|
| Authors: | Imre Miklós Szilágyi Lisheng Wang Csaba Balázsi György Pokol |
| Affiliation: | a Materials Structure and Modeling Research Group of the Hungarian Academy of Sciences, Budapest University of Technology and Economics, H-1111 Budapest, Szt. Gellért tér 4, Hungary b Department of Materials Science and Engineering, 314 Old Engineering Building, SUNY, Stony Brook, NY 11794-2275, USA c Ceramics and Nanocomposites Laboratory, Research Institute for Technical Physics and Materials Science, H-1121 Budapest, Konkoly-Thege út 29-33, Hungary d Department of Inorganic and Analytical Chemistry, Budapest University of Technology and Economics, H-1111 Budapest, Szt. Gellért tér 4, Hungary |
| Abstract: | Hexagonal tungsten oxide (h-WO3) was prepared by annealing hexagonal ammonium tungsten bronze, (NH4)0.07(NH3)0.04(H2O)0.09WO2.95. The structure, composition and morphology of h-WO3 were studied by XRD, XPS, Raman, 1H MAS (magic angle spinning) NMR, scanning electron microscopy (SEM), and BET-N2 specific surface area measurement, while its thermal stability was investigated by in situ XRD. The h-WO3 sample was built up by 50-100 nm particles, had an average specific surface area of 8.3 m2/g and was thermally stable up to 450 °C. Gas sensing tests showed that h-WO3 was sensitive to various levels (10-50 ppm) of NH3, with the shortest response and recovery times (1.3 and 3.8 min, respectively) to 50 ppm NH3. To this NH3 concentration, the sensor had significantly higher sensitivity than h-WO3 samples prepared by wet chemical methods. |
| Keywords: | A Oxides Semiconductors C X-ray diffraction Electron microscopy D Electrical properties |
| 本文献已被 ScienceDirect 等数据库收录！ | |