Gas sensing selectivity of hexagonal and monoclinic WO3 to H2S |
| |
| Authors: | Imre Miklós Szilágyi Sami Saukko János Mizsei Attila L Tóth János Madarász György Pokol |
| |
| Institution: | 1. Materials Structure and Modeling Research Group of the Hungarian Academy of Sciences, Budapest University of Technology and Economics, Department of Inorganic and Analytical Chemistry, H-1111 Budapest, Szt. Gellért tér 4, Hungary;2. Microelectronics and Materials Physics Laboratories, University of Oulu, FIN-90014 Oulu, Finland;3. Department of Electron Devices, Budapest University of Technology and Economics, Goldmann Gy. ter 3, Budapest 1521, Hungary;4. Research Institute for Technical Physics and Materials Science, Hungarian Academy of Sciences, H-1121 Konkoly-Thege út 29-33, Budapest, Hungary;5. Department of Inorganic and Analytical Chemistry, Budapest University of Technology and Economics, H-1111 Budapest, Szt. Gellért tér 4, Hungary |
| |
| Abstract: | Hexagonal and monoclinic tungsten oxide (h- and m-WO3) samples were produced by annealing hexagonal ammonium tungsten bronze, (NH4)0.07(NH3)0.04(H2O)0.09WO2.95 at 470 and at 600 °C, respectively. Their structure, composition and morphology were analyzed by XRD, Raman, XPS, 1H-MAS NMR and SEM. In order to study the effect of crystal structure on the gas sensitivity of tungsten oxides, h- and m-WO3 were tested as gas sensors to CH4, CO, H2, NO and H2S (1000 and 10 ppm) at 200 °C. Monoclinic WO3 responded to all gases, but its gas sensing signal was two magnitudes greater to 10 ppm H2S than to other gases, and it also detected H2S even at 25 °C. Hexagonal WO3 responded only to 10 ppm H2S. Its sensitivity was smaller compared to m-WO3, however, the response time of h-WO3 was significantly faster. The gas sensing tests showed that while m-WO3 had relative selectivity to H2S in the presence CH4, CO, H2, NO; h-WO3 had absolute selectivity to H2S in the presence these gases. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
