Assembly And Gas Sensing Properties Of Heterogeneous Zinc Oxide Nanorod Arrays

The ZnO nanorod array was deposited on the ZnO nanoparticulate film by chemical bath deposition method,on the surface of which the SnO₂ and TiO₂ were loadeded by hydrothermal and solventhermal method,respectively.The morphology and structure of SnO₂-ZnO and TiO₂-ZnO nanorod arrays were characterized by field emission scanning electron microscope?FESEM?,transmission electron microscope?TEM?,X-ray photoelectron spectroscopy?XPS?and X-ray diffraction?XRD?.The results indicated that the cross-linked nanorods constructed the relatively regular ZnO nanorod array.The single crystal nanorod crystallized in the wurtzite phase with the length 2?m and the diameter 30-50 nm.The SnO₂ nanorod and nanoparticle single crystals were distributed on the surface of ZnO nanorod array with the length 50 nm,the diameter 10 nm of the nanorod and the particle size about 5-10 nm of the nanoparticles.The particle size of the polycrystal TiO₂ in TiO₂-ZnO nanorod array was a few nanometer.The ZnO nanorod array and the composited nanorod arrays exhibited high sensitivity and rapid response-recovery characteristics to the testing gases.The sensitivity of pure ZnO nanorod array to 100?L/L acetone and ethanol at 330 ^oC was17 and 13,respectively.After being loaded with SnO₂ on the surface of ZnO nanorods,the heterogeneous SnO₂-ZnO showed higher selectivity to ethanol.What's more,the working temperature is lowered from 330 to 290 ^oC.The sensitivity of SnO₂-ZnO nanorod array to 100?L/L ethanol gas at 290 ^oC achieved 65.It could detect ethanol vapor as low concentration as 0.1?L/L.The selectivity of the ZnO nanorod array to HCHO was greatly improved by loading of TiO₂ on the surface of the nanorod.The sensitivity of TiO₂-ZnO nanorod array to 100?L/L HCHO at 217 ^oC was 278.The response of the TiO₂-ZnO nanorod array to 0.01?L/L HCHO is 53.