铜镍基纳米催化剂的制备及其对硝基苯酚催化性能研究

发布时间：2018-01-03 21:08

本文关键词：铜镍基纳米催化剂的制备及其对硝基苯酚催化性能研究　出处：《新疆大学》2016年硕士论文　论文类型：学位论文

【摘要】：对硝基苯酚(4-NP)是一种常见的环境污染物,其毒性大,结构稳定,自然条件下降解效率低。4-NP加氢还原可以得到对氨基苯酚(4-AP),该产物是一种重要的有机中间体。虽然由4-NP还原制备4-AP在热力学上是可行的,但是受到动力学限制,需要选择合适的催化剂。传统的催化剂是Pt、Au、Ag等贵金属,而贵金属价格昂贵、资源稀缺,因此研究一种廉价的替代催化剂是很必要的。本文主要设计了几种廉价金属的催化剂,并对它们的催化加氢活性进行了研究。主要研究内容与结论如下:(一)Ni/C复合纳米片制备及催化性能研究:在氩气气氛下,以硫酸钠为模板,焙烧油酸镍前驱体,制备得到Ni/C复合纳米片。通过调节焙烧温度,获得三种催化剂:Ni/C-400,Ni/C-500和Ni/C-600。在Ni/C复合纳米片中,C纳米片可以阻止Ni纳米粒子的团聚和长大。三种催化剂中Ni纳米粒子的平均粒径分别是2.63 nm,2.78 nm和2.84 nm。将Ni/C-400,Ni/C-500和Ni/C-600应用于催化还原4-NP反应中,反应的表观反应速率常数(kapp)分别达到0.019 min-1,0.175 min-1和1.239 min-1。Ni/C-600的催化活性高出许多文献报道的贵金属的催化活性。(二)碳包覆的NiO和CuO纳米中空球的制备及催化性能研究:首先,通过熔融盐焙烧法制备了Ni/C和Cu/C复合纳米片。然后,将获得的复合纳米片在空气气氛中焙烧,利用Kirkendall效应制备出碳包覆的NiO和CuO纳米中空球。N2吸附-脱附测试表明,外层的碳膜和内层的中空金属氧化物都是介孔的。反应物分子可以由孔道进入到中空体系中,这将大大提高催化剂的比表面积和活性位点。同时,包覆的碳膜可以有效提高中空球的结构稳定性。将制备的NiO和CuO纳米中空球应用于催化还原4-NP反应,反应的kapp分别是0.4118 min-1和0.5984min-1。(三)碳包覆的NiO/CuO复合纳米中空球的制备及催化性能研究:据文献报道,相比于单独的NiO和CuO,两者的复合物NiO/CuO往往可以表现出更优异的性能。本文通过将镍源和铜源加入到制备体系中,获得了碳包覆的NiO/CuO复合纳米中空球。TEM-mapping结果表明,在NiO/CuO复合纳米中空球结构中,Ni,Cu和O元素的分布是均匀的。此外,N2吸附-脱附测试表明,外层的碳膜和内层的中空金属氧化物都是介孔的。将制备的NiO/CuO纳米中空球应用于催化还原4-NP反应,反应的kapp高达1.5032 min-1。
[Abstract]:P-nitrophenol (4-NP) is a common environmental pollutant, its toxicity, stable structure, can obtain p-aminophenol under natural conditions, the degradation efficiency of low.4-NP hydrogenation (4-AP), the product is a kind of important organic intermediates. Although the 4-NP reduction preparation of 4-AP is feasible in thermodynamics. But by the dynamic limit, you need to select the appropriate catalyst. The catalyst is Pt, Au, Ag and other precious metals, and precious metals are expensive, the scarcity of resources, so the study of an alternative low-cost catalyst is necessary. This paper designed several cheap metal catalysts, and their catalytic activity for the hydrogenation of were studied. The main research contents and conclusions are as follows: (a) on the catalytic properties and preparation of Ni/C composite nano film: under argon atmosphere with the sodium sulfate as the template, roasting nickel oleic acid precursor, preparation of Ni/C composite nano film. Adjusting the calcination temperature, obtained three kinds of catalysts: Ni/C-400, Ni/C-500 and Ni/C-600. in Ni/C nano composite film, nano C can prevent the aggregation of Ni nanoparticles and the average grain grow up. Three kinds of catalysts of Ni nanoparticles in diameter were 2.63 nm, 2.78 nm and 2.84 nm. Ni/ C-400, Ni/C-500 and Ni/C-600 application in catalysis 4-NP reduction reaction, reaction rate constant of the reaction surface (Kapp) catalytic activity reached 0.019 min-1,0.175 min-1 and 1.239 min-1.Ni/C-600 respectively. The high catalytic activity of many precious metals reported in the literature. (two) preparation and catalytic properties of carbon coated NiO and CuO nano hollow spheres: first, through molten salt roasting preparation of Ni/C and Cu/C composite nano film. Then, the composite nano film in air atmosphere roasting, preparation of carbon coated NiO and CuO nano hollow ball.N2 adsorption desorption effect using Kirkendall system The test shows that the hollow metal oxide carbon membrane outer and inner layer is mesoporous. The reactant molecules can enter into the hollow hole by the system, which will greatly increase the surface area of the catalyst and the active site. At the same time, carbon film coating can effectively improve the structural stability of hollow spheres. The preparation of NiO CuO and nano hollow spheres used in catalytic reduction of 4-NP reaction, Kapp reaction were 0.4118 min-1 and 0.5984min-1. (three) preparation and catalytic properties of carbon coated NiO/CuO composite nano hollow spheres: according to the literature, compared to separate NiO and CuO, both of the NiO/CuO complexes can often exhibit superior performance. Through the source of nickel and copper source added to the preparation system, the carbon coated NiO/CuO composite nano hollow ball.TEM-mapping results showed that in NiO/CuO composite nano hollow sphere structure, Ni, Cu and O elements The distribution is uniform. In addition, the N2 adsorption desorption test shows that the outer carbon film and the inner hollow metal oxide are mesoporous. The NiO/CuO hollow spheres are applied to the catalytic reduction of 4-NP reaction. The Kapp of the reaction is as high as 1.5032 min-1..

【学位授予单位】：新疆大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：O643.36

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