多孔铜铈基纳米催化材料的制备、表征及其催化性能的研究

发布时间：2018-04-16 22:36

本文选题：CeO_2-CuO + 多孔材料　；参考：《内蒙古大学》2015年硕士论文

【摘要】：近年来,化石能源的大量消耗导致的温室效应和资源枯竭等问题日益突出。氢能作为一种安全可再生、无污染的新型能源,受到广泛关注。其中,质子交换膜燃料电池是较为有效的氢能利用方式。然而,目前所用的氢燃料中常含有0.3-1%的CO,会毒化燃料电池的Pt电极,缩短电池使用寿命。采用CO优先氧化去除所含氢燃料中微量CO是最为有效的氢燃料净化途径之一。而贵金属和非贵金属催化剂是可应用于富氢气氛中CO优先氧化的两类主要的催化剂。CeO2-CuO基催化剂作为非贵金属催化剂的代表逐渐成为研究热点。CeO2-CuO基非贵金属催化剂原料来源广泛,价格便宜,对CO有较高转化率,对CO2有较好选择性,在较高温度有较好催化活性。然而,这类催化剂反应温度窗口较窄,限制了其实际应用。针对上述CeO2-CuO基催化剂的应用瓶颈问题,本文采用胶体晶体模板法,结合前驱体热分解方法,制备了一系列多孔CeO2-CuO基催化材料,对其富氢气氛中CO优先氧化性能进行了系统研究,获得了在较宽温度窗口具有优异催化性能的CeO2-CuO基催化材料,该类催化材料在质子燃料膜电池氢燃料净化领域具有重要的应用价值。本文第一章对氢能与质子燃料膜电池进行了概述,并对富氢气氛中CO优先氧化催化材料的研究现状进行了综述。本文第二章以胶体晶体为模板,利用前驱体热分解方法制备了一系列多孔CeO2-CuO基催化材料。所制备的CeO2-CuO基催化材料具有连贯有序的大孔结构,孔径约为200 nm。同时,大孔结构的孔壁存在3-4 nm的介孔,形成大孔-介孔共存的多孔结构。这类大孔-介孔结构共存的多孔结构的形成,导致CeO2-CuO基催化材料具有较大的比表面积,Ce02与CuO之间产生强的协同相互作用,使其在富氢气氛中具有优异的CO优先氧化性能。同时,通过在CeO2-CuO基催化材料中引入CO304和Fe203等助催化剂,可在一定程度上调节CO优先氧化反应的温度窗口,使其在较宽的反应温度窗口展现出优异的CO优先氧化性能。本文第三章以胶体晶体为模板,利用前驱体热分解方法制备了多孔Ce02,并采用沉积-沉淀法在Ce02上负载了CuO,制备了多孔CuO/CeO2基催化材料。所制备的多孔CuO/CeO2基催化材料孔径均一,连贯有序,比表面积较大。CuO/CeO2基催化材料在富氢气氛中CO优先氧化的反应活性测试显示,CO选择性随着CuO负载量的增加而升高,当CuO负载量达到10%时,对CO选择性达到最佳。此时,CuO多以高分散状态分布于Ce02表面,高分散的CuO物种与Ce02间的强的相互协同作用,极大地促进了富氢气氛中CO优先氧化反应的进行。本文第四章对论文研究工作进行了总结,并对未来研究进行了展望。
[Abstract]:In recent years, the problems of Greenhouse Effect and resource depletion caused by fossil energy consumption have become increasingly prominent.Hydrogen energy, as a kind of safe renewable, non-polluting new energy, has received extensive attention.Among them, proton exchange membrane fuel cell (PEMFC) is an effective way to utilize hydrogen energy.However, the hydrogen fuel used at present often contains 0.3-1% of CO. it can poison Pt electrode of fuel cell and shorten the life of fuel cell.The removal of trace CO from hydrogen fuel by CO preferential oxidation is one of the most effective ways to purify hydrogen fuel.However, noble metal and non-noble metal catalysts are two main catalysts for CO preferential oxidation in hydrogen-rich atmosphere. CeO2-CuO-based catalysts, as representatives of non-noble metal catalysts, have gradually become the focus of research. CeO2-CuO based non-noble metal catalysts have been widely used as raw materials.It has the advantages of lower price, higher conversion of CO, better selectivity to CO2, and better catalytic activity at higher temperature.However, the temperature window of this kind of catalyst is narrow, which limits its practical application.In this paper, a series of porous CeO2-CuO catalyst materials were prepared by colloidal crystal template method and precursor thermal decomposition method. The catalytic properties of CO preferential oxidation in hydrogen-rich atmosphere were systematically studied.CeO2-CuO based catalytic materials with excellent catalytic performance in a wide temperature window have been obtained, which have important application value in hydrogen fuel purification of proton fuel membrane cells (PEMFC).In the first chapter, hydrogen energy and proton fuel membrane cells are reviewed, and the research status of catalytic materials for CO preferential oxidation in hydrogen-rich atmosphere is reviewed.In the second chapter, a series of porous CeO2-CuO based catalytic materials were prepared by thermal decomposition of precursor using colloidal crystal as template.The prepared CeO2-CuO-based catalyst has a coherent and ordered macroporous structure with a pore size of about 200 nm.At the same time, there are 3-4 nm mesopore in the pore wall of the macroporous structure, forming a porous structure with macroporous and mesoporous coexistence.The formation of this kind of porous structure with macroporous and mesoporous structure leads to a strong synergistic interaction between Ce02 and CuO with large specific surface area, which results in excellent CO preferential oxidation performance in hydrogen-rich atmosphere.At the same time, the temperature window of CO preferential oxidation reaction can be adjusted to a certain extent by introducing CO304 and Fe203 cocatalysts into CeO2-CuO based catalytic materials, so that the excellent CO preferential oxidation performance can be shown in the wider reaction temperature window.In the third chapter, porous ce _ (02) was prepared by thermal decomposition of precursor using colloidal crystal as template, and CuO was supported on Ce02 by deposit-precipitation method to prepare porous CuO/CeO2 based catalytic material.The pore size uniformity, coherence and order of the porous CuO/CeO2 catalyst materials, and the large specific surface area of CuO / CEO _ 2 based catalyst materials, showed that the CO selectivity increased with the increase of the amount of CuO loading in the hydrogen-rich atmosphere.When the load of CuO reaches 10, the selectivity of CO is optimized.In this case, the highly dispersed CuO species are distributed on the surface of Ce02, and the strong interaction between highly dispersed CuO species and Ce02 greatly promotes the CO preferential oxidation in hydrogen-rich atmosphere.The fourth chapter summarizes the research work and prospects for future research.
【学位授予单位】：内蒙古大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：O643.36;TM911.4

【参考文献】