不同微观形貌和晶型氧化铟纳米催化剂的制备及其光催化降解甲苯性能的研究

发布时间：2018-04-28 06:07

  本文选题：光催化降解 + 微观形貌调控　； 参考：《大连理工大学》2015年硕士论文

【摘要】：光催化降解有机污染物作为一种高级氧化技术,在环境污染物治理和控制领域内发挥着重要作用。In2O3作为光催化材料,具有光响应能力强、化学稳定性强、热稳定性强和容易合成各种微观形貌等优点,在光催化降解有机污染物方面具有很高的应用价值。然而,In2O3作为光催化材料也有两个显著的缺点：一是由于In2O3材料本身的禁带宽度较大,只对紫外光有较好的吸收能力,而对在太阳光中占很大比重的可见光几乎没有吸收能力,不能充分利用太阳光的光能；二是In2O3材料所产生的光生空穴-电子对容易发生复合,降低了材料的光降解效率。上述两个问题的存在,限制了In2O3材料的光催化性能。本论文通过对In2O3光催化材料进行微观形貌调控和晶型调控,使In2O3材料的光催化性能得到提高。主要研究成果如下：(1)利用溶剂热法制备出无形态纳米颗粒、微米球和空心微米球三种不同微观形貌的bcc-In2O3光催化材料,实现了对In2O3光催化材料的微观形貌调控。然后,对所制备的不同微观形貌样品进行XRD、SEM、TEM、DRS和氮气吸附-脱附表征分析。结果表明空心微米球样品的微观形貌为典型的空心薄壳结构,光吸收边界达到480 nn3,孔径分布集中在2～10 nm,比表面积达到73.8m2/g,具有较强的光催化性能。同时,以气态甲苯为目标降解物,考察了所制备的不同微观形貌样品的光催化降解性能。结果表明空心微米球样品在5 h降解率就已达到97.21%。此外,对样品进行了ESR表征测试,结果表明空心微米球样品能够产生更多的活性自由基。(2)利用溶剂热法成功制备出bcc-/rh-In2O3混晶纳米催化材料以及bcc-In2O3和rh-In2O3两种单晶纳米催化材料,并能通过适当地控制反应时间合成出不同比例的bcc-/rh-In2O3混晶纳米催化材料,实现了对In2O3纳米催化材料的晶型调控。然后对所制备的样品进行了XRD、SEM、TEM、HRTEM和DRS表征分析。结果表明bcc-/rh-In2O3混晶样品的微观形貌为“杨梅状”球体,各个晶型的晶面相互重叠和交错,有异相结形成,对可见光的吸收能力为单晶样品的10倍。同时,以气态甲苯为目标降解物,考察了所制备的不同晶型In2O3样品的光催化降解性能。结果表明bcc-/rh-In2O3混晶样品在反应进行到5h时的降解率达到97.65%。
[Abstract]:Photocatalytic degradation of organic pollutants, as an advanced oxidation technology, plays an important role in the field of environmental pollutant treatment and control. The advantages of high thermal stability and easy to synthesize all kinds of micro-morphology have high application value in photocatalytic degradation of organic pollutants. However, as a photocatalytic material, in _ 2O _ 3 also has two obvious disadvantages: first, because of the wide band gap of In2O3 material itself, it only has a better absorption capacity to ultraviolet light, but it has almost no absorption ability to visible light, which accounts for a large proportion of the solar light. The photo-cavity-electron pair produced by In2O3 materials is easy to be recombined, which reduces the photodegradation efficiency of the materials. The existence of these two problems limits the photocatalytic performance of In2O3 materials. In this paper, the photocatalytic properties of In2O3 photocatalytic materials were improved by controlling the morphology and crystal morphology of In2O3 photocatalytic materials. The main results are as follows: (1) three kinds of bcc-In2O3 photocatalytic materials with different morphologies were prepared by solvothermal method, including amorphous nanoparticles, microspheres and hollow microspheres, which can control the morphology of In2O3 photocatalytic materials. Then, the samples with different micromorphology were analyzed by XRDX SEM Tem DRS and nitrogen adsorption-desorption schedule. The results show that the microstructure of the hollow microspheres is a typical hollow thin shell structure with a light absorption boundary of 480 nm ~ 3, a pore size distribution of 2 ~ 10 nm and a specific surface area of 73.8 m ~ 2 / g. It has strong photocatalytic properties. At the same time, the photocatalytic degradation of gaseous toluene was investigated. The results showed that the degradation rate of hollow microspheres reached 97.21 in 5 h. In addition, the samples were characterized by ESR. The results show that the hollow micron spheres can produce more active free radicals.) bcc-/rh-In2O3 mixed nanocrystalline nanocatalysts and bcc-In2O3 and rh-In2O3 nanocrystalline catalytic materials were successfully prepared by solvothermal method. Different proportions of bcc-/rh-In2O3 mixed nanocrystalline catalyst materials can be synthesized by properly controlling the reaction time, and the crystal shape of In2O3 nanocrystalline catalyst materials can be controlled. The samples were characterized by TEM and DRS. The results show that the microcosmic morphology of the bcc-/rh-In2O3 mixed crystal sample is "bayberry" sphere, the crystal planes of each crystal form overlap and intersect, and there are heterogeneous junctions, and the absorption ability to visible light is 10 times of that of the single crystal sample. At the same time, the photocatalytic degradation of different crystalline In2O3 samples was investigated with gaseous toluene as the target degradation material. The results showed that the degradation rate of bcc-/rh-In2O3 mixed crystal samples reached 97.65 when the reaction lasted for 5 h.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X701;O643.36
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本文编号：1814090