Preparation And Properties Of Multi-stage Structure Antimony Trioxide Ammonia Sensitive Materials

Ammonia is an important part of industrial and domestic waste gas.It is colorless,has a strong irritating odor,and it can stimulate human skin and respiratory mucosa,causing lung swelling and even death.Therefore,real-time and effective monitoring of ammonia is necessary.Metal oxide semiconductor gas sensors have wide application prospects in real-time monitoring of gas environments due to their advantages of high selectivity,high sensitivity,fast response and recovery,good reproducibility,excellent stability,and low manufacturing cost.Dy₂O₃ is a rare earth metal oxide with the unique physicochemical properties of rare earth metal oxides.However,in the field of gas sensors,Dy₂O₃ material has not been reported.Therefore,this paper designs and synthesizes Dy2O3 materials with different 3D hierarchical structure.The morphology and structure of the synthesized Dy2O3 nanomaterials were analyzed by scanning electron microscopy?SEM?,transmission electron microscopy?TEM?and X-ray diffraction?XRD?.The gas-sensitivity properties of Dy₂O₃ for ammonia gas were tested.The influence of morphology on the material properties was also discussed.The content of this thesis mainly includes the following parts:?1?Dysprosium acetylacetonate is selected as the dysprosium source.Alkaline environment is provided by urea.Anhydrous methanol is used as the reaction solvent.The mixture is heated in the autoclave to 180^oC for 12 h.After the solvent heat reaction product was washed,it was heat-treated at 500^oC for 2 h to obtain the coral-like multi-level Dy₂O₃ nanomaterials.The coral-like multi-level Dy₂O₃ nanomaterials are formed by nanoparticles with a diameter of about 12.3±3.6 nm.The precursors of Dy₂O₃ nanomaterials are formed by nanoparticles into white spike soft coral,and the sintered Dy2O3 nanomaterials are aggregated by nanoparticles to form red coral.The coral-like multi-level Dy2O3 nanomaterials has good selectivity to ammonia at room temperature.The ammonia sensitivity of 100 ppm is as high as 13.4.It can detect as low as 0.1 ppm of ammonia.?2?Keep the reaction raw material unchanged,change the reaction solvent to anhydrous methanol and deionized water?volume ratio is 1:1?,and make it react at180^oC for 12 h under high pressure conditions.The solvothermal reaction product was treated at a high temperature of 560°C for 2 hours to obtain a peony-like multi-level structure Dy₂O₃ nanomaterial,which is about 1-3?m.The peony-like multi-level Dy₂O₃nanomaterials is constructed from nanowires and nanosheets.Nanosheets are stacked from nanowires.Nanowires are made of nanoparticles.The peony-like multi-level Dy₂O₃ nanomaterials has good selectivity to ammonia at room temperature,and have a sensitivity of up to 20.6 to ammonia at 100 ppm.It can detect as low as 5 ppb of ammonia.?3?In the reaction solvent is a mixture of anhydrous methanol and deionized water?3:1 volume ratio?,high temperature and high pressure reaction is performed using acetylacetonate hydrazine and urea.The reaction temperature was 180^oC and the reaction time was 2 h.The obtained product was heat-treated at 650^oC for 2 hours to obtain the tube-like Dy2O3 nanomaterials,which is about 200-250 nm.The tube-like Dy₂O₃ nanomaterials is constructed from nanoparticles.The tube-like Dy₂O₃nanomaterials has good selectivity to ammonia at room temperature,and has a sensitivity of up to 26.4 to ammonia at 100 ppm.It can detect as low as 1 ppb of ammonia.