氧化锌和氧化钨微纳米材料的可控制备及性能研究

发布时间：2018-10-21 14:51

【摘要】：微纳米材料因独特的物理化学性能在催化、传感、储能领域具有广泛的应用,因此制备新颖的金属氧化物纳米材料、控制其形貌的结晶尺寸与维度、研究其生长机制等成为该领域研究的热点,促进人们深入研究微纳米结构与材料功能之间的关系,高效利用微纳米结构使其产业化。本论文以半导体金属氧化物(ZnO和WO_3)微纳米材料为研究对象,制备出新颖的ZnO和WO_3纳米材料,并探讨其可能形成的机理,测试了半导体材料的光催化性能或者气敏活性。(1)采用水热法,利用丙三醇辅助合成出三维花球状的ZnO纳米结构,分布均匀,其花球状的直径约在5 μm。根据不同的反应时间,提出了纳米材料可能的形成机制即成核-溶解-重结晶的生长机理。我们考察了 ZnO的气敏活性,花球状ZnO对丙酮表现出良好的气敏活性,随着丙酮浓度的升高,气敏活性也增高。在200ppm丙酮下,更快的响应时间为8s,恢复时间为2s。(2)采用简单和环境友好的水热路线合成了六角莲的氧化锌纳米晶体。该结构是由10-20 nm厚度的纳米片组成。我们通过X-射线粉末衍射(XRD)、扫描电子显微镜(SEM)等手段对其结构、形貌和尺寸进行了表征。此外,氧化锌光催化显示良好的光催化活性,并分析了该结构在光催化降解罗丹明B溶液(RhB)的优势。(3)通过乙二胺四乙酸(EDTA)调控下的水热法合成出了山茶花状WO_3,通过对实验条件的控制,我们发现乙二胺四乙酸的结构导向作用对这种独特结构的形成有一定的影响。通过对实验反应时间的控制,我们对这种新颖结构的形成提出了成核-溶解-重结晶的自组装生长机理。合成出的WO_3在对亚甲基蓝溶液(MB)的降解中表现出较高的光催化活性。(4)我们通过直接沉淀法制备出金属盐,利用无机盐作为"牺牲模板"制备出双壳状WO_3空心微球。我们通过X-射线粉末衍射(XRD)、扫描电子显微镜(SEM)和场发射透射电镜(TEM)手段对其的结构、形貌和尺寸进行了表征。此外,我们还通过热重(TG)和Brunauer-Emmett-Teller(BET)分析来分析双壳状WO_3微球。这种三维分层的结构有较大的比表面和介孔结构,并具有较好的光催化性能。
[Abstract]:Because of its unique physical and chemical properties, micronanomaterials are widely used in the fields of catalysis, sensing and energy storage. Therefore, novel metal oxide nanomaterials are prepared to control the crystal size and dimension of their morphology. The study of its growth mechanism has become a hot topic in this field, which promotes the in-depth study of the relationship between microstructures and the function of materials, and makes efficient use of microstructures to industrialize them. In this thesis, novel semiconductor metal oxide (ZnO and WO_3) nanomaterials were prepared and the possible mechanism of their formation was discussed. The photocatalytic properties or gas sensing activity of semiconductor materials were tested. (1) Three-dimensional flower globular ZnO nanostructures were synthesized by hydrothermal method, and their diameter was about 5 渭 m. According to different reaction time, the possible formation mechanism of nanomaterials, that is, nucleation, dissolution and recrystallization, was proposed. The gas-sensitive activity of ZnO was investigated. The flower-shaped ZnO showed a good gas-sensitive activity to acetone, and the gas-sensitive activity increased with the increase of acetone concentration. Under 200ppm acetone, the faster response time is 8 s and the recovery time is 2 s. (2) the hexagonal ZnO nanocrystals were synthesized by a simple and environmentally friendly hydrothermal route. The structure is composed of 10-20 nm nanowires. The structure, morphology and size were characterized by X ray powder diffraction (XRD) (XRD), scanning electron microscopy (SEM). In addition, zinc oxide showed good photocatalytic activity. The advantages of this structure in photocatalytic degradation of (RhB) in Rhodamine B solution were analyzed. (3) Camellia-like WO_3, was synthesized by hydrothermal method under the control of ethylenediamine tetraacetic acid (EDTA). We found that the structure orientation of ethylenediamine tetraacetic acid has a certain influence on the formation of this unique structure. By controlling the reaction time, the mechanism of nucleation, dissolution and recrystallization is proposed. The synthesized WO_3 showed high photocatalytic activity in the degradation of (MB) in methylene blue solution. (4) the metal salts were prepared by direct precipitation, and the hollow WO_3 hollow microspheres were prepared by inorganic salts as "sacrificial templates". The structure, morphology and size were characterized by X-ray powder diffraction (XRD),) scanning electron microscope (SEM) and field emission transmission electron microscopy (TEM). In addition, the double shell WO_3 microspheres were analyzed by thermogravimetric (TG) and Brunauer-Emmett-Teller (BET) analysis. The three dimensional layered structure has larger specific surface and mesoporous structure and has better photocatalytic performance.
【学位授予单位】：天津工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB383.1;O643.36

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