| In this work,the walnut-like?-Bi2MoO6,flower-like?-Bi2Mo3O122 and spherical MoO3/?-Bi2Mo3O12 with hierarchical structures were fabricated via a sample solvothermal route by optimizing the preparation conditions involving in the ratio of solvent,reaction temperature and reaction time.The X-ray diffraction meter?XRD?,X-ray photoelectron spectroscope?XPS?,scanning electron microscope?SEM?and transmission electron microscope?TEM?were used to analyze the structure and the morphology of the products.The materials were assembled into gas sensors to detect toxic gases such as hydrogen sulfide and trimethylamine.The main content was made up as below:?1?The walnut-like hierarchical Bi2MoO6 hollow microspheres,assembled by nanosheets,were synthesized by a facile solvothermal method based on MoO3 hollow spheres and Bi?NO3?3·5H2O.The sensor based on Bi2MoO6 calcined at 400oC can detect 0.1 ppb H2S gas with high response?S=1.98?at low temperature of 133oC.In addition,the sensing mechanism also was discussed based on XPS and gas chromatography-mass spectrometry?GC-MS?analyses.?2?The flower-like hierarchical?-Bi2Mo3O12 microspheres were prepared with commercial MoO3 and Bi?NO3?3·5H2O by a facial solvothermal method.The sensor based on?-Bi2Mo3O12 calcined at 500oC can detect 1 ppb100 ppm H2S with fast response and recovery speed.Moreover,the XPS and GC-MS analyses were applied to investigate the sensing mechanism.?3?According to Chapter?2?,the hierarchical MoO3/?-Bi2Mo3O12 microspheres were fabricated by adjusting the amounts of MoO3 and Bi?NO3?3·5H2O and the reaction temperature,followed by calcining at 500oC.The sensor based on MoO3/?-Bi2Mo3O12can detect 0.1100 ppm TMA with a better linear relationship at low temperature of 170oC.Furthermore,in order to investigate the TMA sensing mechanism,the XPS spectra of the sensor were tested before and after the sensor exposure to TMA at 170°C. |
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