基于嵌段共聚物胶束构筑银—二氧化钛纳米粒子及其表征

发布时间：2018-02-13 11:33

本文关键词： Ag-Ti O2纳米粒子两亲性嵌段共聚物自组装溶胶凝胶法光催化　出处：《山东理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：二氧化钛(Ti O2)纳米材料具有无毒、价格低廉、易合成等特点而被广泛应用于太阳能电池、催化剂载体等方面,特别是在光催化方面得到重要应用。国内外研究人员进行了大量的掺杂实验,其中贵金属纳米粒子掺杂可以增大纳米粒子的表面积,能够有效的改善Ti O2纳米材料的催化性能。本文研究了利用嵌段共聚物自组装技术,合成具有核壳结构的银纳米粒子(Ag NPs)和具有中空结构的银金纳米粒子(Ag Au NPs)的制备方法。结合溶胶凝胶法,制备了具有高催化性能的银-二氧化钛(Ag-Ti O2)纳米粒子及银金-二氧化钛(Ag Au-Ti O2)纳米粒子。首先,分别利用嵌段共聚物聚苯乙烯-b-聚乙烯基吡啶(PS-b-P2VP)与硝酸银(Ag NO3)在四氢呋喃中发生自组装。及聚乙烯基吡啶-b-聚氧化乙烯(P2VP-b-PEO)与硝酸银(Ag NO3)在四氢呋喃/N,N-二甲基甲酰胺溶剂中发生自组装。实验选择利用紫外灯照射还原的方法制备出Ag NPs,在紫外光照射条件下银离子发生还原反应生成Ag NPs,且形态为核壳结构。反应过程无需高温。实验结果表明,嵌段共聚物和Ag NO3的质量比,是Ag NPs的尺寸发生改变的主要影响因素。其次,利用嵌段共聚物自组装,结合溶胶凝胶法制备Ag-Ti O2纳米粒子,通过控制溶胶凝胶的滴加量,调控Ag-Ti O2纳米粒子的尺寸及外壳厚度。对制备的Ag-Ti O2复合纳米粒子进行了催化性能的研究实验。通过在紫外灯照射下利用制备的样品降解亚甲基蓝溶液实验,研究了Ag-Ti O2纳米粒子的光催化效率。实验结果表明,每组实验中当加入溶胶凝胶含量为5%SG时,Ag-Ti O2纳米粒子的光催化效果最好。在完成Ag-Ti O2纳米粒子制备方法研究的基础上,研究了双金属纳米粒子的制备方法。以制备的具有核壳结构的银纳米粒子作为牺牲模板,因为Ag+/Ag的标准还原电势(0.80Vvs)低于Au Cl4-/Au的标准还原电势(0.99Vvs标准氢电极),可以利用金银间简单的电子置换反应进行实验。实验过程中当HAu Cl4溶液与制备好的Ag NPs的溶液混合时,Au Cl4-发生氧化反应,部分Ag原子会发生还原反应生成银离子。最终成功制备出Ag Au双金属复合复合纳米粒子。通过改变金和银(Au:Ag)的比例,可以改变合金粒子的组分及结构,当Au:Ag为0.2时,制备出具有中空结构的Ag Au双金属纳米粒子。结合溶胶凝胶法,成功制备出Ag Au-Ti O2复合纳米粒子。Ag-Ti O2及Ag Au-Ti O2纳米粒子的外貌形态可以通过透射电镜及高分辨透射电镜观察。以制备的样品为催化剂,进行光降解浓度为5mg/L的亚甲基蓝溶液,讨论了不同组分的Ti O2复合纳米粒子的光催化效率。实验结果表明Ag Au-Ti O2复合纳米粒子比纯Ti O2复合纳米粒子光催化性能提高了42%。
[Abstract]:TIO _ 2 / TIO _ 2 nanomaterials are widely used in solar cells, catalyst carriers and so on for their advantages of non-toxic, low price and easy synthesis. Especially in photocatalysis, researchers at home and abroad have carried out a large number of doping experiments, in which noble metal nanoparticles doping can increase the surface area of nanoparticles. The catalytic properties of TIO _ 2 nanomaterials can be improved effectively. In this paper, the self-assembly technology of block copolymers was studied. Methods for the synthesis of silver nanoparticles with core-shell structure (Ag NPs) and silver gold nanoparticles with hollow structure (Ag au NPs). Ag-TiO _ 2) nanoparticles with high catalytic activity and Ag Au-Ti O _ 2 nanoparticles with silver gold and titanium dioxide were prepared. The block copolymers PS-b-P2VP) and silver nitrate Ag no _ 3) were used to self-assemble in tetrahydrofuran, respectively, and in tetrahydrofuran / NNN-dimethylformyl (NNN-dimethylformyl), respectively, and in tetrahydrofuran / NNN- dimethyl formacylformic acid (PNN- dimethylformyl) and polyvinylpyridine -b- polyvinyl oxide (P2VP-b-PEO) and silver nitrate silver nitride (Agno _ 3), respectively. The Ag NPs were prepared by ultraviolet lamp irradiation reduction method. Silver NPs were synthesized by silver ion reduction under UV irradiation, and the structure of Ag NPs was core-shell structure. The reaction process did not require high temperature. The results of the experiment show that. The mass ratio of block copolymers to Ag NO3 is the main factor influencing the size change of Ag NPs. Secondly, Ag-Ti O 2 nanoparticles were prepared by block copolymer self-assembly and sol-gel method. The size and shell thickness of Ag-Ti O 2 nanoparticles were regulated. The catalytic properties of the prepared Ag-Ti O 2 composite nanoparticles were studied. The degradation of methylene blue solution by the prepared samples under UV irradiation was studied. The photocatalytic efficiency of Ag-Ti O 2 nanoparticles was studied. The results showed that the photocatalytic efficiency of Ag-TiO 2 nanoparticles was the best when the sol gel content was 5 SG in each group. The preparation method of bimetallic nanoparticles was studied. Silver nanoparticles with core-shell structure were used as sacrificial templates. Because the standard reduction potential of Ag / Ag is 0.80 V / v / s) lower than that of au Cl4-/Au 0.99V vs standard hydrogen electrode, the experiment can be carried out by using the simple electron substitution reaction between gold and silver. During the experiment, the solution of HAu Cl4 and the prepared Ag NPs can be dissolved in the experiment. The oxidation reaction of au Cl 4- occurs when the liquid is mixed. Some Ag atoms will deoxidize to form silver ions. Finally, Ag au bimetallic composite nanoparticles can be successfully prepared. By changing the ratio of au and Ag au / Ag, the composition and structure of the alloy particles can be changed. When Au:Ag is 0.2, Ag-au bimetallic nanoparticles with hollow structure were prepared. The morphology of Ag Au-Ti O 2 composite nanoparticles. Ag-TiO 2 and Ag Au-Ti O 2 nanoparticles can be observed by transmission electron microscopy (TEM) and high resolution transmission electron microscopy (TEM). Using the prepared sample as catalyst, the methylene blue solution with a concentration of 5 mg / L was prepared. The photocatalytic efficiency of TIO _ 2 composite nanoparticles with different composition was discussed. The experimental results show that the photocatalytic performance of Ag Au-Ti _ 2 composite nanoparticles is better than that of pure TIO _ 2 composite nanoparticles.
【学位授予单位】：山东理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.1

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