铋系复合材料的氧化—还原合成及光催化与电化学性能研究

发布时间：2018-06-01 01:24

本文选题：铋系材料 + 光催化　；参考：《鲁东大学》2017年硕士论文

【摘要】：随着人民生活水平的提高和经济的飞速发展,环境污染和资源短缺逐渐成为人类面临的巨大挑战。光催化技术能够利用太阳能降解环境中的有害物质,高能量密度的锂离子电池作为一种能量存储形式在生活中具有广泛的应用。因此,如何高效地利用和转换太阳能以及开发其他新能源成为解决这两大问题的有效途径。铋系材料因其独特的层状结构、良好的光电性能以及低廉的成本,引起了人们的极大兴趣,并且在光催化降解有机污染物和促进能源存储和转换等方面具有很大的应用前景。本论文通过氧化还原的方法,设计并合成了Bi系基的一系列复合纳米材料,构筑异质结结构的复合光催化材料促进光生电荷的有效分离,提高光催化降解有机污染物效率。以KMnO_4为氧化剂,通过氧化还原反应制备出BiOCl/MnO_x纳米复合材料和Bi_2O_2CO_3/MnCO_3纳米复合材料,并将Bi_2O_2CO_3/MnCO_3纳米复合材料经过500°C高温煅烧转变成了Bi_2O_3/MnO_x纳米复合材料作为锂离子电池的负极材料。通过三步法成功合成AgBr量子点耦合的多孔BiOBr。首先以乙二醇为还原剂通过简单的溶剂热法制备多孔Bi;然后通过氧化还原反应以NH4Fe(SO_4)2为氧化剂氧化多孔Bi来制备多孔BiOBr球;最后通过原位沉淀法,在BiOBr球上沉积AgBr量子点。采用X射线粉末衍射(XRD)和透射电镜(TEM)等表征手段对所制备样品的物相和形貌进行表征。结果表明:直径为500 nm的三维分层BiOBr微球是由大量的纳米片相互交错构成;AgBr量子点分散BiOBr片表面而没有改变主相BiOBr的微观结构和形态。BiOBr/AgBr复合材料在降解罗丹明B方面比纯的BiOBr多孔球具有更好的光催化活性。通过氧化还原反应以KMnO_4为氧化剂氧化Bi纳米球制备出BiOCl/MnO_x复合材料。采用X射线粉末衍射(XRD)、扫描电镜(SEM)和透射电镜(TEM)等表征手段对不同条件下所制备样品的物相和形貌进行表征,探究复合材料BiOCl/MnO_x的电化学性能。实验结果表明:BiOCl/MnO_x复合材料是由一些纳米片组装的小球和一些不规则的片状物组成,随着KMnO_4量的增加BiOCl/MnO_x复合材料中不规则的片状物逐渐减少,规则的自组装小球状结构逐渐增多,且形貌和尺寸变得比较均匀单一。随着KMnO_4的量增加BiOCl/MnO_x复合材料的存储能力和循环稳定性变得更好。通过氧化还原反应以KMnO_4为氧化剂氧化Bi纳米球制备出Bi_2O_2CO_3/MnCO_3复合材料,并将Bi_2O_2CO_3/MnCO_3复合材料经过500°C高温煅烧转变成了Bi_2O_3/MnO_x复合材料。采用X射线粉末衍射(XRD)、扫描电镜(SEM)和透射电镜(TEM)等表征手段对不同条件下所制备样品的物相、形貌行表征,探究Bi_2O_2CO_3/MnCO_3和Bi_2O_3/MnO_x复合材料的电化学性能。实验结果表明:Bi_2O_2CO_3/MnCO_3复合材料是由一些片状组成的圆球和少量正方体结构组成的,随着KMnO_4量的增加,样品中会出现一些更小的微球及纳米线,煅烧之后Bi_2O_3/MnO_x复合材料变的比较疏松多孔。与Bi_2O_2CO_3/MnCO_3复合材料相比Bi_2O_3/MnO_x复合材料具有更好的可逆性,随着KMnO_4的量增加所制得样品具有更好的存储能力和循环稳定性。
[Abstract]:With the improvement of people's living standards and the rapid development of economy, environmental pollution and shortage of resources are becoming a great challenge for human being. Photocatalytic technology can use solar energy to degrade harmful substances in the environment. Lithium ion batteries with high energy density are widely used in life as a form of energy storage. So, such as The efficient use and conversion of solar energy and the development of other new energy sources have become an effective way to solve these two problems. Bismuth system materials have attracted great interest due to their unique layered structure, good photoelectric performance and low cost, and they also have a great interest in photocatalytic degradation of organic pollutants and the promotion of energy storage and conversion. In this paper, a series of composite nanomaterials of Bi based on the redox method have been designed and synthesized in this paper to construct a composite photocatalyst of heterostructure to promote the effective separation of light generated charge and to improve the efficiency of photocatalytic degradation of organic pollutants. KMnO_4 is used as an oxidant and redox reaction is prepared. BiOCl/MnO_x nanocomposites and Bi_2O_2CO_3/MnCO_3 nanocomposites were transformed into Bi_2O_3/MnO_x nanocomposites as negative materials for lithium ion batteries by calcining Bi_2O_2CO_3/MnCO_3 nanocomposites at 500 degrees C at high temperature. The porous BiOBr. coupled with AgBr quantum dots was successfully synthesized by three steps. A porous Bi was prepared by a simple solvent heat method, and then porous BiOBr spheres were prepared by oxidation-reduction reaction with NH4Fe (SO_4) 2 as oxidant to oxidize porous Bi. Finally, AgBr quantum dots were deposited on BiOBr spheres by in situ precipitation. The samples were prepared by X ray powder diffraction (XRD) and transmission electron microscopy (TEM). The results show that the three dimensional layered BiOBr microspheres with a diameter of 500 nm are composed of a large number of nanoscale microspheres, and the AgBr quantum dots disperse the BiOBr surface without changing the main phase BiOBr, and the microstructure and morphology.BiOBr/AgBr composites have better light acceleration than the pure BiOBr porous spheres in the degradation of the Luo Danming B side. The BiOCl/MnO_x composite was prepared by oxidizing Bi nanospheres with KMnO_4 as oxidant. X ray powder diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to characterize the phase and morphology of the samples prepared under different conditions, and the electrochemical properties of the composite BiOCl/MnO_x were investigated. The experimental results show that the BiOCl/MnO_x composite is composed of some small spheres assembled by some nanoscale and some irregular flakes. With the increase of the amount of KMnO_4, the irregular patches in the BiOCl/MnO_x composites gradually decrease, and the regular self assembled spherules gradually increase, and the morphology and size become more uniform and single. With the KMnO, the morphology and size of the composite are more uniform and single. The storage capacity and cyclic stability of BiOCl/MnO_x composites are better. Bi_2O_2CO_3/MnCO_3 composites are prepared by oxidation reduction reaction with KMnO_4 as oxidant to oxidize Bi nanospheres, and Bi_2O_2CO_3/MnCO_3 composites are converted to Bi_2O_3/MnO_x composites through 500 degree high temperature calcination. X ray powder is used. The final diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) are used to characterize the phase and morphology of the samples prepared under different conditions and explore the electrochemical properties of Bi_2O_2CO_3/MnCO_3 and Bi_2O_3/MnO_x composites. The results show that the Bi_2O_2CO_3/MnCO_3 composite is a sphere composed of some flakes and a small number of square bodies. With the increase of KMnO_4, some smaller microspheres and nanowires will appear in the sample. After calcining, the Bi_2O_3/MnO_x composite becomes porous and porous. Compared with the Bi_2O_2CO_3/MnCO_3 composite, the Bi_2O_3/MnO_x composite has a better reversibility, and the samples are better with the increase of the amount of KMnO_4. Storage capacity and cyclic stability.
【学位授予单位】：鲁东大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB332

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