钯基纳米材料的可控合成及其小分子催化性能研究

发布时间：2018-05-31 03:07

本文选题：纳米钯铜合金 + 花状氧化镍　；参考：《河南师范大学》2015年硕士论文

【摘要】：备受世界关注的纳米材料是多学科交叉的国际前沿研究领域。本论文综述了纳米材料的最新研究进展,概括了纳米材料的最新分类、最新的制备手段以及在新的研究领域的应用。基于对以上内容的分析,本论文以近几年来一直备受人们关注并倡导的环境友好,经济,节能的化学反应目标为出发点,选择了有应用前景的钯基纳米材料为主要研究内容,探究了溶剂、非贵金属以及结构独特的氧化物载体对Pd基纳米材料的合成、负载量以及性能等方面的影响,得到了一些有意义的结果。论文主要开展了以下几部分的研究工作:一、羟基数目不同的醇对Pd/XC-72催化材料的合成以及催化性能的影响。我们通过常见的湿化学法,分别用乙醇、乙二醇、丙三醇作溶剂,以经济环保的碳颗粒(XC-72)为载体,少量谷氨酸作螯合剂,氯化亚钯溶液作为活性金属源,一步溶剂热分别得到三种不同的Pd/C纳米材料;接着对所合成的三种催化剂Pd/XC-72(EA),Pd/XC-72(EG),Pd/XC-72(GI)进行苯甲醇氧化测试,结果发现,具有多羟基的丙三醇作溶剂得到的Pd/C纳米材料拥有最好的催化活性;Pd/XC-72(EG)次之,Pd/XC-72(EA)最差。进一步对所得样品进行了XRD、TEM等表征,结果表明丙三醇作溶剂合成的Pd/C催化剂与另外两种催化剂相比具有较高的金属负载量、较好的分散性以及较小的适于催化的金属粒径,这些可能是其催化性能最好的原因。二、掺有非贵金属Cu的Pd基纳米材料的合成及其催化CO氧化性能研究。以便宜易得的碳颗粒为载体,溶剂热法一釜合成了不同比例的Pd Cu双金属合金催化剂,并且经同样的制备方法分别合成了单金属催化剂Pd/XC-72和Cu/XC-72,样品的后续处理采用冷冻干燥法干燥所制备的所有催化剂,得到了疏松无凝结、分散性好、粒径小的Pd Cu/XC-72合金催化剂。通过对所得样品一系列物理化学表征和催化性能测试,可以得出含有贵金属Pd的Pd Cu合金催化剂和单质Pd/XC-72催化剂均对CO氧化表现出了很好的催化性能。综合催化剂各项物理化学性质,以减少贵金属用量为基准,则是比例为1:3的合金催化剂Pd Cu/XC-72为最优催化剂;此外测试分析结果还表明,非贵金属Cu的加入改变了Pd面心立方结构的晶面构成,同时还有利于Pd的分散和负载,改善其催化活性位点;而Pd的存在同样有助于Cu的还原和负载;两种金属相互促进,与载体共同作用形成了性能更好的合金材料。三、纳米Pd Cu/花状Ni O(Pd Cu/F-Ni O)的合成及其CO催化氧化性能。我们以常见的表面活性剂十六烷基三甲基氯化铵(CTAC)作为结构导向剂,Ni2+为中心金属离子,尿素溶液为沉淀剂,低温合成出分散性好、由9nm厚的纳米薄片组装构成的花状Ni(OH)2·x H2O。以这种花状Ni(OH)2·x H2O为前驱体,通过空气高温煅烧得到构型基本不变的花状Ni O。接着对微米花状Ni O进行了FE-SEM、XRD、TEM以及催化CO氧化性能等测试,结果表明得到的Ni O属于斜方六面体晶系,漂亮的花型结构由表面带有孔洞的粗糙的约为9nm厚的薄片交错组装而成。以制得的单分散的花状Ni O作为载体负载Pd Cu双金属合成复合催化剂催化CO氧化,该催化剂在常温条件下即对CO氧化表现出了良好的催化性能。
[Abstract]:Nanomaterials, which have attracted much attention from the world, are the international frontiers of interdisciplinary research. This paper summarizes the latest research progress of nanomaterials, summarizes the latest classification of nanomaterials, the latest preparation methods and applications in new research fields. Based on the analysis of the above content, this paper has been the most popular in recent years. The objective of environmental friendly, economic and energy saving chemical reaction is the starting point, and the application prospect of palladium based nanomaterials is selected as the main research content. The effects of solvent, non precious metal and unique oxide carrier on the synthesis, negative load and properties of Pd based nanomaterials are explored. The main research work of this paper is the following parts: first, the effect of hydroxyl number of different alcohols on the synthesis and catalytic properties of Pd/XC-72 catalytic materials. We use ethanol, ethylene glycol, glycerol as solvent by common wet chemical method, and a small amount of glutamic acid as the carrier and a small amount of glutamic acid. The chelating agent and palladium chloride solution are used as active metal sources. Three different Pd/C nanomaterials are obtained by one step solvent heat. Then the synthesis of three kinds of catalysts, Pd/XC-72 (EA), Pd/XC-72 (EG) and Pd/XC-72 (GI), are tested for benzyl alcohol oxidation. The results show that the Pd/C nanomaterials with polyhydroxy glycerol as solvent are the best. The catalytic activity of Pd/XC-72 (EG) and Pd/XC-72 (EA) were the worst. The results were further characterized by XRD, TEM and so on. The results showed that the Pd/C catalyst synthesized by the glycerol as solvent had higher metal load, better dispersibility and smaller size suitable for catalytic metal particles, which may be its urging. Two, the synthesis of Pd based nanomaterials with non precious metal Cu and their catalytic CO oxidation properties. With the cheap and easy available carbon particles as the carrier, different proportions of Pd Cu bimetal alloy catalysts were synthesized by solvothermal method, and the single metal catalyst Pd/XC-72 and Cu/XC were synthesized by the same preparation method. -72, after the subsequent treatment of the samples, all the catalysts prepared by freeze-drying were used to obtain the Pd Cu/XC-72 alloy catalyst, which had no condensation, good dispersibility and small particle size. Through a series of physical and chemical characterization and catalytic performance test of the obtained samples, the Pd Cu alloy catalyst containing precious metal Pd and the single substance Pd/XC-72 could be obtained. All the chemicals have good catalytic performance for the oxidation of CO. In addition to the physical and chemical properties of the catalysts, the 1:3 alloy catalyst Pd Cu/XC-72 is the best catalyst for reducing the amount of precious metals. Furthermore, the test analysis also shows that the addition of non precious metal Cu has changed the composition of the crystal surface of the Pd face center cubic structure. It is also beneficial to the dispersion and load of Pd to improve its catalytic activity sites, and the presence of Pd also contributes to the reduction and load of Cu; the two metals promote each other to form a better alloy material with the support of the carrier. Three, the synthesis of nano Pd Cu/ flower like Ni O (Pd Cu/F-Ni O) and its CO catalytic oxidation performance. The active agent, sixteen alkyl three methyl ammonium chloride (CTAC), as the structure guide, Ni2+ as the central metal ion and the urea solution as the precipitator, is synthesized at low temperature. The flower like Ni (OH) 2. X H2O. composed of 9nm thick nanoscale slices is used as the precursor of this kind of flower like Ni (OH) 2. X H2O, and the configuration is basically unchanged through the high temperature calcination of air. The flower like Ni O. then tests the FE-SEM, XRD, TEM, and catalytic CO oxidation properties of micron flower like Ni O. The results show that the obtained Ni O belongs to the trapezoid hexahedral system, and the beautiful flower structure is composed of a rough surface with a rough surface with a hole and about the 9nm thicker. The bimetallic composite catalyst can catalyze CO oxidation. The catalyst exhibits good catalytic performance for CO oxidation at room temperature.
【学位授予单位】：河南师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.1;O643.36

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