纳米级稀土材料在汽车尾气净化中的应用

汽车尾气是当今大气污染的主要来源之一 ,催化净化是国际普遍采用的汽车尾气净化法。本文根据我国贵金属贫乏而稀土资源丰富的国情 ,以及稀土纳米材料特有的性质和功能 ,综述了纳米级稀土材料在汽车尾气净化中的应用及其发展前景     

稀土在汽车尾气净化催化剂中的应用现状

详细叙述了用稀土部分替代汽车尾气净化催化剂中铂、铑等贵金属的研究和应用情况.主要包括:①稀土在汽车尾气净化催化剂中应用优势;②稀土催化剂净化汽车尾气中几种主要有害气体的作用机理;③我国从事尾气净化稀土催化剂研究、开发的主要单位和他们各自的研究重点及取得的成果;④稀土三元催化剂的组成、特点及富氧条件下分解NOx的作用机理;⑤纳米稀土催化剂的开发与展望,指出:当纳米稀土催化剂研制成功,可望实现不使用贵金属达到与贵金属催化剂同样的净化效果;⑥稀土催化剂的应用前景.预料,在我国随着汽车保有量的迅速增加,尾气净化催化剂将成为稀土消费的主要领域之一.     

改性纳米二氧化钛在净化汽车尾气中的应用研究

为了研究光催化材料TiO2对隧道内汽车尾气的净化效果,首先采用溶胶-凝胶法制备纳米二氧化钛光催化剂,采用不同掺量的Fe3+改性纳米TiO2,并在500℃焙烧得到样品,然后利用自制尾气净化设备进行净化试验,接着对其进行X衍射(XRD)测定和红外光谱(IR)分析。结果显示,掺杂Fe3+能够同时捕获电子和空穴,从而降低电子空穴对的复合几率,提高纳米二氧化钛的光催化性能,弱紫外光条件下对CO、CO2、HC、NOx的净化效率比未掺杂的纳米TiO2分别能提高0.6%、0.6%、2.3%、8.2%。     

稀土复合催化剂对柴油车尾气净化效果的影响研究

采用共沉降法制备了不同成分的复合氧化物与钙钛矿型涂层,将此涂层负载于堇青石和SiC蜂窝陶瓷载体上制成柴油车尾气四效净化器,研究了催化器对柴油车尾气的净化效果,同时对阳离子表面活性剂、无机触变剂等添加剂对涂层性能的影响进行了研究。通过N2吸附法、X射线衍射法(XRD)、差热分析法(DTA)等方法对催化剂涂层比表面积、热稳定性等进行了测试评价;模拟柴油车尾气中颗粒物组成(C),采用DTA方法测试了复合催化剂对颗粒物起燃温度的降低程度;柴油发动机台架实验结果表明,净化后的尾气HC、CO、颗粒物以及NOx的排放分别为0.03、0.17、0.007和4.78g/(kW.h);复合催化剂将碳烟的起燃温度降低至411℃,对微粒过滤器的再生非常有利。     

柴油车尾气净化催化剂发展趋势

汽车因排放大量的CO2气体，破坏了大气的臭氧层，造成了全球的温室效应，使整个地球气温变暖，气候异常，所以需要对汽车生产进行产能限制，同时对汽车进行节能减排。由于柴油车热效高、功率大，具有良好的经济性和可靠性，所以柴油车的生产现已得到突飞猛进的发展。介绍了柴油车尾气净化催化剂的发展过程、催化剂使用的原理及催化剂组成，并提...     

柴油车尾气净化催化剂发展趋势

汽车因排放大量的CO2气体,破坏了大气的臭氧层,造成了全球的温室效应,使整个地球气温变暖,气候异常,所以需要对汽车生产进行产能限制,同时对汽车进行节能减排。由于柴油车热效高、功率大,具有良好的经济性和可靠性,所以柴油车的生产现已得到突飞猛进的发展。介绍了柴油车尾气净化催化剂的发展过程、催化剂使用的原理及催化剂组成,并提出了柴油车尾气净化催化剂的问题与展望。     

稀土纳米材料及应用——稀土纳米合金

稀土应用广泛，我们对稀土合金材料介绍一下：     

黄磷尾气净化制甲醇

黄磷尾气富含一氧化碳,回收利用黄磷尾气生产甲醇,减少环境污染,获取高附加值的产品,为黄磷尾气资源的综合利用开辟新的出路。     

稀土纳米氧化物的应用及生产技术

稀土元素本身具有丰富的电子结构,表现出许多光、电、磁的特性。稀土纳米化后,表现出许多特性,如小尺寸效应、高比表面效应、量子效应、极强的光电磁声性质、超导性、高化学活性等,能大大提高材料的性能和功能,又开发出许多新功能材料。在光学材料、发光材料、晶体材料、磁性材料、电池材料、电子陶瓷、工程陶瓷、催化剂等高新科技领域,将发挥重要的作用。     

Application of Rare Earths in Thermal Barrier Coating Materials

Rare earths are a series of minerals with special properties that make them essential for applications including miniaturized electronics, computer hard disks, display panels, missile guidance, pollution controlling catalysts, H2-storage and other advanced materials. The use of thermal barrier coatings （TBCs） has the potential to extend the working temperature and the life of a gas turbine by providing a layer of thermal insulation between the metallic substrate and the hot gas. Yttria （Y203）, as one of the most important rare earth oxides, has already been used in the typical TBC material YSZ （yttria stabilized zirconia）. In the development of the TBC materials, especially in the latest ten years, rare earths have been found to be more and more important. All the new candidates of TBC materials contain a large quantity of rare earths, such as R2Zr207 （R=La, Ce, Nd, Gd）, CeO2-YSZ, RMeAI11019 （R=La, Nd; Me=Mg, Ca, Sr） and LAP04. The concept of double-ceramic- layer coatings based on the rare earth materials and YSZ is effective for the improvement of the thermal shock life of TBCs at high temperature.     

稀土氧化物纳米材料制备的研究进展

稀土氧化物纳米材料的合成与制备近年来已成为国内外学者研究的一个热点。本文介绍了国内外稀土氧化物纳米材料制备及合成方法的研究进展,并对稀土氧化物纳米材料的制备方法进行了分类。同时,综合比较了各自的优点和缺点,并对各种制备方法在各个领域的应用前景进行了一定的展望。     

高压气体终端净化技术在标准气体配制中的应用

介绍了气体高压净化技术在标准气体制备中的应用,随着标准气体制备难度加大及市场竞争加剧,该技术将得到广泛的应用。多年的实验结果表明该技术具有广阔的市场空间。     

Preparation of Rare Earth Hydroxide and Oxide Nanoparticles by Precipitation Method

A series of rare earth hydroxide and oxide nanoparticles have been prepared by precipitation method with alcohol as the dispersive and protective reagent. Transmission electron microscope (TEEM) images indicate that the particles are spherical in shape and smaller than 100 nm in size. The crystallite sizes of cubic Ln2O3 have lanthanide shrinking effect, while average crystal lattice distortion rates possess lanthanide swelling effect. The diffraction peak intensity of heavy rare earth oxide nanometer powders is remarkably stronger than that of light rare earth oxide nanometer powders. The variation of diffraction intensity with atomic number presents an inverted W type, forming a double peak structure. Fourier transform infrared (FTIR) spectrums reveal that Ln2O3 nanopowders have higher surface activity than that of ordinary Ln2O3 powders. The UV-vis spectra show that Ln-O bond of these particles is slightly blue-shifted, and its absorption intensity decreases.     

The Application of the Rare Earths to Magnesium and Titanium Metallurgy in Australia

Rare earth elements (REEs) have found application in metallurgical processes for nearly a century due to their unique chemical and physical properties but have gained increased attention in recent decades. Notably, the use of these elements may assist in the development of advanced magnesium and titanium products for applications spanning biomedicine, aerospace, and the automotive industry. To this end, current progress in this area, highlighting work done in Australian research organizations with particular academic expertise, is reviewed. Two areas that require further research are identified: the application of Sc and the heavy lanthanides to the development of novel magnesium alloys and the use of REEs as additives in the development of additive manufacturing of titanium parts.     

稀土在银基接触材料中的作用与应用

介绍了稀土在银及银合金电接触材料中的作用、特点及影响效果,阐述了国内外稀土银合金电接触材料的应用情况,展望了稀土银合金的发展前景。     

汽车尾气净化催化剂的研究现状及其进展

综述了汽车尾气净化催化剂的3个组成部分－载体、活性涂层和活性组分的研究现状及其研究进展，指出了汽车尾气净化催化剂中急需解决的关键问题。     

Behaviour of Rare Earths in Solid Solution in Steel

The contents of rare earth metals(REM) insolid solution in 16 Mn steel were determined bymeans of inductive coupling plasma (ICP)spectroscopy.The amount of REM in solid solutionis only a few ppm in the steel with MnS inclusions,which rises slightly with the increasing of REMcontent in steel.At RE/S>1.9,the MnS inclu-sions in steel disappear completely,the REM con-tent in solid solution increases rapidly with the in-creasing of REM content.The solubility of ceriumin 16 Mn steel(st 52)is less than 0.011 wt—％ atroom temperature.The results obtained indicate that REM in sol-id solution reduce the amount of pearlite and in-crease that of ferrite and its microhardness.Dis-solved REM oculd increase temperature of criticalpoints,alleviate band structnre and suppressgrowth of austenite grains.     

微量稀土元素在铸钢中的应用

综述了近几年稀土在铸钢中的应用研究现状 ,分析了稀土在铸钢中的作用机理及对铸钢性能的影响 ,指出了铸钢中加入稀土的原则 ,提出了今后的研究方向