Pd系纳米合金合成以及催化性质研究

发布时间：2018-04-29 06:26

本文选题：钯 + 镍　；参考：《安徽大学》2015年硕士论文

【摘要】：贵金属纳米颗粒由于其优异的催化性能而在许多重要的催化领域得到了广泛的应用。近年来很对课题组发现贵金属钯与其它贵金属相比,稳定性高,催化效果好,可以用于催化很多的有机反应。更为重要的是,随着合成方法的改进和单晶衍射技术的发展,贵金属(Pd,Pt,Au,Ag)与非贵金属(Fe,Co,Ni,Cu等等)形成的合金纳米材料已经吸引了很多科学研究组对其形貌,结构,尺寸大小,组成以及催化性能进行研究,但真正具有特殊形貌,尺寸均一,可回收循环利用的高效催化性能的催化剂还很有限。目前,最具代表性的催化体系是具有不同的几何形态学,电子结构和协同效应的双金属合金纳米催化剂,已经发现它们可作为高活性催化剂应用于有机合成,电催化,传感器和临床诊断学方面。这类多功能催化剂由于协同效应不仅具有单一成分金属的性质而且还具有多金属的特殊催化性质。利用掺杂了非贵金属的特点,减少了贵金属的利用率,利用这种协同作用,提高了催化效率,利用这种可回收循环利用的性质,符合绿色化学的要求,是新一代理想的催化剂,是贵金属纳米催化领域的研究热点。本文就在前人的研究基础上,合成钯系纳米合金,应用于催化有机反应,研究贵金属纳米合金催化剂的结构,形貌,组成以及催化活性。主要内容如下：1.本文通过共还原的一步法有效合成一系列组分可控的钯镍纳米合金,在这个合成过程中,油胺作为溶剂和还原剂,三苯基膦作为配体稳定剂对于合成这样一系列的单分散纳米合金有着重要的作用。Pd-Ni合金具有均一的尺寸并且组成可通过改变前驱体的比例来调控。我们研究这些合金对于Miyauru-Heck反的催化活性,实验结果表明,合金比等量的Pd的催化效果好,并且Pd1Ni1在一系列的合金中催化效果最好。最重要的是,Pd-Ni合金同样可以催化Heck反应的一系列底物。2.本文采用一步法制备尺寸和形貌均一的球状的钯银纳米合金催化剂,并通过用X射线衍射仪(XRD)、透射电子显微镜(TEM)、高分辨电子显微镜(HRTEM)等对其结构和形貌进行表征。实验结果表明,通过改变温度能够很好地调控其形貌。在此基础上,研究了Pd-Ag纳米颗粒的有机催化性能。实验表明,当Pd-Ag合金的形貌为均一的球形的时候,催化Suzuki偶联反应产率最高。
[Abstract]:Noble metal nanoparticles have been widely used in many important catalytic fields due to their excellent catalytic properties. In recent years, it has been found that palladium has higher stability and better catalytic effect than other precious metals, so it can be used to catalyze many organic reactions. More importantly, with the improvement of the synthesis method and the development of single crystal diffraction technique, the alloy nanomaterials formed by the noble metal PdPtPtAg-Ag and the non-precious metal FeCoCoNI-Cu) have attracted many scientific research groups on their morphology, structure, size, etc. The composition and catalytic performance of the catalyst were studied, but the catalyst with special morphology, uniform size and recyclable high performance catalyst is still very limited. At present, the most representative catalytic systems are bimetallic alloy nanocatalysts with different geometric morphology, electronic structure and synergistic effect. It has been found that they can be used as highly active catalysts for organic synthesis and electrocatalysis. Sensors and clinical diagnostics. Because of the synergistic effect, this kind of multifunctional catalysts have not only the properties of single component metals but also the special catalytic properties of polymetallic catalysts. The utilization rate of precious metals is reduced by doping non-precious metals, and the catalytic efficiency is improved by using this synergistic effect. The properties of recycling and recycling are in line with the requirements of green chemistry and are the new generation of ideal catalysts. It is a hotspot in the field of nanometer catalysis of noble metals. In this paper, palladium nanocrystalline alloys were synthesized on the basis of previous studies, and were used to catalyze organic reactions. The structure, morphology, composition and catalytic activity of noble metal nano-alloy catalysts were studied. The main content is as follows: 1. In this paper, a series of controllable palladium and nickel nanocrystalline alloys were synthesized by one step co-reduction method. In this process, oleamine was used as solvent and reducing agent. Triphenylphosphine as a ligand stabilizer plays an important role in the synthesis of such a series of monodisperse nanoalloys. Pd-Ni alloys have uniform size and their composition can be controlled by changing the proportion of precursors. We have studied the catalytic activity of these alloys for Miyauru-Heck inversion. The experimental results show that the catalytic activity of these alloys is better than that of the same amount of PD, and that of Pd1Ni1 is the best in a series of alloys. The most important is that Pd-Ni alloy can also catalyze a series of substrates of Heck reaction. In this paper, spherical palladium and silver nanocrystalline catalysts with uniform size and morphology were prepared by one-step method. The structure and morphology of the catalysts were characterized by X-ray diffractometer (XRD), transmission electron microscopy (TEM) and HRTEM (high resolution electron microscope). The experimental results show that the morphology can be well controlled by changing the temperature. On this basis, the organic catalytic properties of Pd-Ag nanoparticles were studied. The results show that the yield of catalytic Suzuki coupling reaction is the highest when the morphology of Pd-Ag alloy is uniform and spherical.
【学位授予单位】：安徽大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.1;O643.36

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