基于对硝基苯酚还原反应的贵金属纳米粒子类催化材料研究

发布时间：2019-06-02 21:35

【摘要】：近年来,由于贵金属纳米粒子特殊的物理和化学性质使其在催化领域具有潜在的应用价值,这引起了研究者的广泛关注。金属纳米粒子具有很高的表面能,其很容易发生团聚,团聚后其催化性能明显下降。为了阻止其团聚获得高催化性能,一般将金属纳米粒子装载到材料载体中。本论文基于二氧化过硅纳米粒子为模板分别制备了载Pd纳米粒子复合聚电解质空心微球、载Au纳米粒子复合发状聚离子液体空心微球和载Au聚合物刷复合微球,并对它们催化硼氢化钠还原4-硝基苯酚的性能进行了研究。第一章绪论本章主要介绍五种类型的纳米金(钯)催化材料,归纳了纳米金催化材料的最新研究进展;重点讨论了纳米金催化材料的制备手段及其催化活性、稳定性、可回收性和可重复使用性;并对纳米金催化材料的发展方向和今后需解决的关键问题进行了展望。第二章负载钯纳米粒子的聚电解质空心微球的制备及其还原对硝基苯酚的催化活性用表面引发原子转移自由基聚合法(SI-ATRP)在二氧化硅纳米粒子表面接枝聚碘化甲基丙烯酸三甲基胺基乙酯(PMETAI),原位还原静电吸附的Pd Cl62-后刻蚀去除二氧化硅模板,成功制备Pd纳米粒子复合聚电解质空心微球(air@PMETAI@Pd)。用透射电子显微镜(TEM)、红外光谱仪(FTIR)、能谱仪(EDX)、热重分析仪(TGA)对所制备的复合空心微球进行表征。结果表明Pd纳米粒子均匀负载在聚电解质微球上,其直径约为1.5±0.2nm。将负载Pd纳米粒子的微球作为催化剂应用于硼氢化钠还原4-硝基苯酚反应,显示出良好的催化效果且具有较好的回收利用性。第三章负载金纳米粒子发状聚离子液体空心微球的制备及其催化性能研究通过二步SI-ATRP和还原HAu Cl4在二氧化硅纳米粒子表面分步接枝聚离子液体(PMIMC)网络壳层,温度响应性聚合物刷(PDMAEMA)和Au纳米粒子,制备了一种智能空心复合材料(air@PMIMC-PDMAEMA-Au)。TEM、FTIR、EDX、XRD、XPS和TGA技术手段对所制备的发状聚离子液体空心微球进行了表征。结果表明Au纳米粒子均匀负载在PMIMC-PDMAEMA壳层上,其直径约为1.5±0.2 nm。采用于硼氢化钠还原4-硝基苯酚反应研究所制备空心微球的催化性能。我们发现PMIMC壳层和PDMAEMA刷这种交联结构让该催化剂催化还原4-硝基苯酚反应有很高的催化性能和稳定性。此外,我们还发现该空心微球还原4-硝基苯酚的催化活性具有温度调控性。第四章载金聚合物刷复合微球的制备及其催化性能研究通过SI-ATRP在二氧化硅纳米粒子表面接枝聚N-异丙基丙烯酰胺(PNIPAM),原位还原吸附在PNIPAM刷中的HAu Cl4,成功制备了载Au聚合物刷复合微球(Si O2@PNIPAM-Au NPs)。用TEM、FTIR和EDX等技术手段对所制备的聚合物刷微球进行了表征。结果表明,Au纳米粒子在聚合物刷微球上的负载量低,粒径较大,分布不均匀。将载Au聚合物刷复合微球作为催化剂应用于硼氢化钠还原4-硝基苯酚反应,显示出的催化效果不如Au纳米粒子复合发状聚离子液体空心微球(air@PMIMC-PDMAEMA-Au)和Pd纳米粒子复合聚电解质空心微球(air@PMETAI@Pd)。
[Abstract]:In recent years, because of the special physical and chemical properties of noble metal nanoparticles, it has potential application value in the field of catalysis. The metal nanoparticles have a high surface energy, which can easily be agglomerated, and the catalytic performance of the metal nanoparticles is obviously reduced. In order to prevent its agglomeration to achieve high catalytic performance, metal nanoparticles are typically loaded into the material carrier. The method comprises the following steps of: respectively preparing a Pd nano-particle composite polyelectrolyte hollow microsphere, a loading Au nano-particle composite hair-shaped polyionic liquid hollow microsphere and a loaded Au polymer brush composite microsphere based on the dioxide-silicon nano-particle as a template, The performance of the reduction of 4-nitrophenol with sodium borohydride was studied. The first chapter introduces five types of nano-gold (Au) catalytic materials, and summarizes the latest research progress of the nano-gold catalytic materials. The preparation methods of the nano-gold catalytic materials and their catalytic activity, stability, recyclability and reusability are discussed. The development direction of the nano-gold catalytic material and the key problems to be solved in the future are also discussed. in the second chapter, the preparation of the polyelectrolyte hollow microspheres loaded with the nano-particles and the surface-initiated atom transfer radical polymerization (SI-ATRP) for the surface-initiated atom transfer radical polymerization (SI-ATRP) for the catalytic activity of the nitrophenol are grafted on the surface of the silica nano-particle to obtain the trimethylamino ethyl methacrylate (PMETAI), In-situ reduction of the electrostatic adsorption of Pd Cl62-post-etching to remove the silica template, the Pd nano-particle composite polyelectrolyte hollow microsphere (air@PMETAI @ Pd) was successfully prepared. The prepared composite hollow microspheres were characterized by a thermogravimetric analyzer (TGA). The results show that the Pd nanoparticles are uniformly loaded on the polyelectrolyte microspheres with a diameter of about 1.5 to about 0.2 nm. The microspheres loaded with Pd nano-particles are used as a catalyst to be used for reducing the 4-nitrophenol reaction by sodium borohydride, thus showing good catalytic effect and good recycling property. In the third chapter, the preparation and catalytic properties of the loaded gold nanoparticle-shaped polyionic liquid hollow microspheres were studied by two-step SI-ATRP and reduction of HAuCl4 on the surface of the silica nano-particle by a step-by-step grafting of a polyionic liquid (PMIMC) network shell layer, a temperature-responsive polymer brush (PPMAEMA) and Au nanoparticles. An intelligent hollow composite material (air@PMIMC-PDMAEMA-Au) is prepared. The prepared polyionic liquid hollow microspheres were characterized by TEM, FTIR, EDX, XRD, XPS and TGA. The results show that the Au nanoparticles are uniformly loaded on the PMIMC-PDMAEMA shell, with a diameter of about 1.5 to about 0.2 nm. The catalytic performance of the hollow microspheres was prepared by the reduction of 4-nitrophenol by sodium borohydride. We found that the PMIMC shell layer and the PDMAEMA brush have a very high catalytic performance and stability in the catalytic reduction of 4-nitrophenol by this cross-linking structure. In addition, we have also found that the catalytic activity of the 4-nitrophenol reduced by the hollow microsphere has a temperature control property. In the fourth chapter, the preparation and catalytic properties of the gold-bearing polymer-brush composite microspheres were studied by means of SI-ATRP on the surface of the silica nano-particles, and the HAuCl4 in the PNIPAM brush was reduced, and the Au-containing polymer-brush composite microspheres (Si-O2@PNIPAM-Au NPs) were successfully prepared. The prepared polymer brush microspheres were characterized by TEM, FTIR and EDX. The results show that the loading of Au nanoparticles on the polymer brush microspheres is low, the particle size is large, and the distribution is not uniform. The Au-containing polymer-brush composite microsphere is used as a catalyst to be used for reducing the 4-nitrophenol reaction by sodium borohydride, and the catalytic effect is less than that of the Au nano-particle composite hair-shaped polyionic liquid hollow microsphere (air@PMIMC-PDMAEMA-Au) and the Pd nano-particle composite polyelectrolyte hollow microsphere (air@PMETAI @ Pd).
【学位授予单位】：西北师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：O643.36;TB383.1

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