不同微结构SnO、SnO₂纳米材料的水热法制备及其气敏和光催化性能研究

【作者】 刘斌；

【导师】 杨合情；

【作者基本信息】 陕西师范大学 ， 材料学， 2013， 博士

【摘要】 采用直接反应法、水热法制备出SnO纳米片自组装花状结构、SnO2亚微米棒自组装球形花状结构、SnO2纳米球、SnO2笔状纳米棒、Ag/SnO2复合微球。采用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线衍射仪(XRD)和红外光谱(IR)对产物的形貌和结构进行了表征。研究了不同形貌SnO和SnO2的成核、生长、组装过程,提出了可能的生长机理。研究了不同形貌SnO和SnO2纳米结构的发光特性、光催化特性、气敏特性,探讨了纳米结构的形貌、尺寸与性能之间的关系。这些结果为SnO和Sn02纳米材料的制备、物理化学性能研究以及在光电子、锂离子电池、气敏传感、太阳能电池、光催化等领域的应用奠定了基础。具体研究结果如下：(1)通过SnCl2·2H2O和NaOH在室温下直接反应制备了SnO纳米片自组装花状结构。所制备的SnO花状结构直径为7-9μm,由厚度为200-500nm、直径3-5μm的四方相SnO纳米片自组装而成。研究了不同锡源对产物形貌的影响,提出了可能的生长机理。在室温下研究了SnO纳米片自组装花状结构的光致发光和光催化特性。所制备的SnO纳米片自组装花状结构在390nm处有一强的带边发光峰,在482nm处有一弱的来自于锡空位的发光峰。SnO纳米片自组装花状结构对光降解孔雀石绿的反应是一种有效的催化剂,其催化过程为准一级反应。(2)通过SnCl4·5H2O、NaOH各IPVP在200℃下水热反应24h,制备了SnO2亚微米棒自组装球形花状结构。所制备的SnO2球形花状结构直径在1.7-2.0μm,由直径为300-600nm的亚微米棒自组装而成。研究了PVP在SnO2亚微米棒自组装球形花状结构形成过程中的作用,并提出了可能的生长机理。考察了工作温度和薄膜厚度对SnO2球形花状结构传感器气敏性能的影响,同时测试了SnO2球形花状结构传感器对不同浓度的乙醇和三乙胺的气敏性能。在350℃下,SnO2球形花状结构传感器对105ppm乙醇和45ppm三乙胺的灵敏度分别为3.65和2.97,并与SnO2粉末传感器对比,发现SnO2球形花状结构传感器的灵敏度要高于SnO2粉末传感器。(3)通过SnCl2·2H2O、H2C2O4·2H2O和PVP在200℃下水热反应12h,制备了直径约为230nm的SnO2纳米球。考察了H2C2O4·2H2O和PVP在SnO2纳米球形成过程中的作用,提山了可能的生长机理。测试了SnO2纳米球传感器对不同浓度的甲醇、甲醛、三乙胺和丙酮的气敏性能。在350℃下,SnO2纳米球传感器对30ppm甲醇、16ppm甲醛、9ppm三乙胺和85ppm丙酮的灵敏度分别是1.49、1.47、1.62和1.5,并与Sn02球形花状结构传感器对比,发现SnO2纳米球传感器的灵敏度要高于SnO2球形花状结构传感器。研究了SnO2纳米球光催化降解有机污染物的催化性能,结果表明,SnO2纳米球是光降解孔雀石绿的有效催化剂。(4)通过SnCl4·5H2O、NaOH、Na3C6H5O7·2H2O和PVP在220℃下水热反应24h,制备了直径在320-550nm,长度在2.1-2.9μm的SnO2笔状纳米棒。考察了PVP和Na3C6H5O7·2H2O在SnO2笔状纳米棒形成过程中的作用,提出了可能的生长机理。测试了Sn02笔状纳米棒传感器对不同浓度的甲醇、三乙胺和乙醇的气敏性能。在350℃下,Sn02笔状纳米棒传感器对30ppm甲醇、9ppm三乙胺和21ppm乙醇的灵敏度分别是1.11、2.96和1.35,并与Sn02粉末传感器对比,发现Sn02笔状纳米棒传感器的灵敏度要高于Sn02粉末传感器。(5)在PVP的存在下,通过SnCl4、 NaOH和AgNO3在200℃下水热反应24h,制备了直径在550-850nm的Ag掺杂的Ag/SnO2复合微球。研究了不同AgNO3用量对Ag/SnO2复合微球形成的影响。测试了Ag/SnO2复合微球传感器对不同浓度的丙酮、甲醇、三乙胺和乙醇的气敏性能。在350℃下,Ag/SnO2复合微球传感器对17ppm丙酮、30ppm甲醇、5ppm三乙胺和21ppm乙醇的灵敏度分别是2.04、1.92、2.74和2.04,并与未掺杂Ag的Sn02微球传感器对比,发现Ag/SnO2复合微球的灵敏度要高于Sn02微球传感器。研究了Ag/SnO2复合微球光催化降解有机污染物的催化性能,结果表明,Ag/SnO2复合微球是促进孔雀石绿光降解的有效催化剂,其光催化性能优于未掺杂Ag的Sn02微球。更多还原

【Abstract】 Flowerlike architectures constructed with SnO nanosheets, spherical flowerlike architectures assembled with SnO2submicron rods, SnO2nanospheres, SnO2pencil-like nanorods and Ag/SnO2composite microspheres were synthesized through direct reaction and hydrothermal routes. Morphologies and structures of these products were characterized by means of scanning electron microscopy, transmission electron microscopy, X-ray diffraction and IR spectrum. The processes of nucleation, growth, self-assemble of SnO and SnO2nanostructures with various geometrical morphologies were studied, and the possible growth mechanisms of SnO and SnO2nanostructures were proposed. The photoluminescence, photocatalytic behaviors, and gas-sensing properties of SnO and SnO2nanostructures with various morphologies were studied, and the relations between morphologies, size and properties were investigated. These research results would provide a base for further research on synthesises of SnO and SnO2nanostructures, the physical and chemical properties of SnO and SnO2nanostructures and their applications in photonic and electronic devices, lithium ion storage, gas sensor, solar cell and photocatalyst.(1) Flowerlike architectures constructed with SnO nanosheets were prepared via a direct reaction of SnO2·2H2O with NaOH at room temperature. The SnO flowerlike architectures with diameters of7to9μm are constructed from tetragonal SnO nanosheets with diameters of3to5μm and the thicknesses of200to500nm. The influence of different tin source on morphologies of the products was investigated, and a possible growth mechanism was proposed. The photoluminescence and photocatalytic activity of SnO nanosheet-based flowerlike architectures were studied at room temperature. The results indicate that the flowerlike architectures constructed with SnO nanosheets display a strong band edge emission at390nm and a very weak Sn vacancy related emission at482nm. The flowerlike architectures constructed with SnO nanosheets were effective photocatalyst for the degradation of malachite green. The photodegradation of malachite green catalyzed by the SnO nanosheet-based flowerlike architectures is a pseudo first-order reaction.(2) The spherical flowerlike architectures assembled with SnO2submicron rods were synthesized via a simple hydrothermal reaction of SnCl4-5H2O with NaOH and PVP at200℃for24h. The SnO2spherical flowerlike architectures with diameters of1.7to2.0μm are constructed from submicron rods with diameters of300to600nm. The role of PVP in the growth of spherical flowerlike architectures assembled with SnO2submicron rods was investigated, and a possible growth mechanism was also proposed. The influences of temperature and film thickness on the gas sensing properties of the SnO2spherical flowerlike architectures were investigated. The gas sensing properties of the SnO2spherical flowerlike architectures sensors toward ethanol and triethylamine with different concentration were tested. The sensor response of SnO2spherical flowerlike architectures toward105ppm ethanol and45ppm triethylamine at350℃is3.65and2.97, respectively. The response performance of the sensors based on the SnO2spherical flowerlike architectures toward ethanol and triethylamine is better than that of SnO2powders.(3) The SnO2nanospheres with the diameters of about230nm were synthesized via a simple hydrothermal reaction of SnCl2·2H2O with H2C2O4·2H2O and PVP at200℃for12h. The role of H2C2O4·2H2O and PVP in the growth of SnO2nanospheres was investigated, and a possible mechanism was also proposed. The gas sensing properties of the SnO2nanospheres sensors toward methanol, formaldehyde, triethylamine and acetone with different concentration were tested. The sensor response of SnO2nanospheres toward30ppm methanol,16ppm formaldehyde,9ppm triethylamine and85ppm acetone at350℃is1.49,1.47,1.62and1.5, respectively. The response performance of the sensors based on the SnO2nanospheres toward methanol, formaldehyde, triethylamine and acetone is better than that of SnO2spherical flowerlike architectures. The photocatalytic activity of the as-prepared SnO2nanospheres for the degradation of organic pollutants was studied, and the results indicate that the SnO2nanospheres were effective photocatalyst for the degradation of malachite green.(4) The SnO2pencil-like nanorods were synthesized via a simple hydrothermal reaction of SnCl4·5H2O, NaOH, Na3C6H5O7·2H2O and PVP at220℃for24h. The diameters and lengths of the SnO2pencil-like nanorods are320to550nm and2.1to2.9μm, respectively. The role of PVP and Na3C6H5O7·2H2O in the growth of SnO2pencil-like nanorods was investigated, and a possible mechanism was also proposed. The gas sensing properties of the SnO2pencil-like nanorods sensors toward methanol, triethylamine and ethanol with different concentration were tested. The sensor response of SnO2pencil-like nanorods toward30ppm methanol,9ppm triethylamine and21ppm ethanol at350℃is1.11,2.96and1.35, respectively. The response performance of the sensors based on the SnO2pencil-like nanorods toward methanol, triethylamine and ethanol is better than that of SnO2powders.(5) The Ag doped Ag/SnO2composite microspheres with diameters of550to850nm were synthesized via a simple hydrothermal reaction of SnCl4·5H2O with NaOH and AgNO3in the presence of PVP at200℃for24h. The influence of AgNO3with different quantity on the growth of the Ag/SnO2composite microspheres was investigated. The gas sensing properties of the Ag/SnO2composite microspheres sensors toward acetone, methanol, triethylamine and ethanol with different concentration were tested. The sensor response of the Ag/SnO2composite microspheres toward17ppm acetone,30ppm methanol,5ppm triethylamine and21ppm ethanol at350℃is2.04,1.92,2.74and2.04, respectively. The response performance of the sensors based on the Ag/SnO2composite microspheres toward acetone, methanol, triethylamine and ethanol is better than that of Ag-undoped SnO2microspheres. The photocatalytic activity of the as-prepared Ag/SnO2composite microspheres for the degradation of organic pollutants was studied, and the results indicate that the Ag/SnO2composite microspheres were effective photocatalyst for the degradation of malachite green. The photocatalytic ability of the Ag/SnO2composite microspheres is stronger than that of the Ag-undoped SnO2microspheres.更多还原