重稀土氧化物对钯催化剂活性影响的研究

研究了重稀土氧化物对钯催化剂活性的影响.实验结果表明,添加重稀土氧化物的钯催化剂,其对CO的氧化活性都有提高,特别是Yb2O3.同Pd催化剂相比,添加Yb2O3的钯催化剂,其CO氧化温度有明显下降.     

稀土-过渡金属-贵金属型汽车尾气净化催化剂的研究成果及产业化

在微反色谱装置上研究了负载型Pt，Pt—RE，Pd—Ni—La—Ce，Pd—Co—La—Ce，Pt—Pd—Rh—RE等催化剂的烃转化及一氧化碳氧化的活性和稳定性。用TPR，TPD等方法研究了铂与稀土、载体的相互作用，铂与钯、铑之间的相互作用，研究了催化剂的制备工艺。对稀土一过渡金属一贵金属型催化剂进行了汽车怠速实验，并在国家指定的权威单位进行了二八工况评价试验。结果表明，所研制的三效催化剂达到欧洲Ⅱ标准。     

变价稀土氧化物对催化剂性能的影响

本文从原子结构分析了变价稀土元素原子的结构特点 ,从机理上分析了变价稀土氧化物对催化剂原子氧化价的稳定性、贮氧能力和热稳定性等性能增强的根源 ,从理论上深入认识了稀土氧化物的助催化作用。     

草酸沉淀—等离子体发射光谱法测定稀土精矿中的REO、ThO2和ReO

研究了用草酸沉淀—等离子体发射光谱法测定稀土精矿中的稀土氧化物总量、氧化钍量和稀土氧化物分量。稀土精矿经碱熔融、酸溶除杂后灼烧成氧化物，以重量法测定灼烧产物中稀土氧化物与氧化钍的合量；之后以盐酸溶解灼烧产物，用等离子体发射光谱法测定溶解液中氧化钍量和稀土氧化物分量，稀土氧化物与氧化钍合量减去氧化钍量即为稀土氧化物总量。结果表明：以等离子体发射光谱法测定的稀土氧化物分量之和与重量法测定的稀土氧化物总量吻合；稀土氧化物总量为39.84%,相对标准偏差为2.59%;本法对于2种标准物质稀土精矿REO-30(GSB04-3309—2016)和REO-50(GSB04-3311—2016)的测定值与标准值吻合，表明方法可靠稳定。本法适用于稀土氧化物总量≥20%的稀土精矿中稀土氧化物总量、氧化钍量和稀土氧化物分量的连续测定。     

稀土掺杂对LaSrCoO4催化剂性能的影响

采用聚丙烯胺溶胶-凝胶法制备了类钙钛矿La0.7Nd0.3SrCoO4和La0.7Ce0.3SrCoO4复合氧化物催化剂,考察了它们对CO和C3H8的催化氧化活性,并运用XRD,IR,TPR和TPD等手段对催化剂进行了表征.结果表明,稀土掺杂后的LaSrCoO4复合氧化物均为K2NiF4型结构,不同稀土掺杂对LaSrCoO4复合氧化物的CO和C3H8氧化活性的影响不同,Nd掺杂能增加Co3+、化学吸附氧和晶格氧的数量,提高复合氧化物的活性.     

稀土在苯制顺酐催化剂中的应用

在苯氧化制顺丁烯二酸酐(简称顺酐)的磷-钒系列催化剂中加入少量稀土氧化物,除钆、镝和铥外,其余10种稀土元素均可使顺酐收率提高约3～4%,苯的转化率可达95%以上。用混合氧化物代替单一稀土氧化物,得到大致相同的结果。     

钙钛矿型稀土复合氧化物整体式催化剂的研究进展

概述了钙钛矿型稀土复合氧化物用于燃烧催化剂的发展动态 ,综述了钙钛矿型稀土复合氧化物整体式催化剂的研究进展 ,并分析和归纳了相关的影响因素及其中钙钛矿型稀土复合氧化物粉体的制备技术     

废气净化用锰系稀土氧化物催化剂

针对苯的完全氧化反应,研究了催化剂中锰、铜、稀土和钡的氧化物对催化性能的影响,其活性顺序是锰>铜>稀土>钡。稀土和钡的氧化物的主要作用是提高催化剂的热稳定性和减少热收缩率。该催化剂的活性在苯浓度3×10~(-3)内随苯浓度的降低而有所提高。在空速20000～50000h~(-1)、床层温度400℃时,空速对催化剂活性影响不大。经1000h寿命考核,催化剂活性无下降趋势。本催化剂已在硅钢片涂漆机上使用10个月,净化率70％左右。     

富氢条件下一氧化碳选择性氧化催化剂

本发明提供一种用于富氢条件下一氧化碳选择性氧化催化剂，使用较少量的贵金属，获得更高的低温一氧化碳的氧化活性和选择性。该催化剂由担载在多孔性无机物载体上的贵金属组分和其他金属组分构成。其特征在于，前述贵金属组分可以是下列的贵金属群中至少一种，前述其他金属组分可以是下列的其他金属群中至少一种。贵金属群：铂、钌、金、铑、钯；其他金属群：铁、钛、锆、钡、锡、钨、锌、钼、铈、镧。本发明的催化剂贵金属含量低，并可有效应用于一氧化碳在富氢气氛下的选择性氧化。本发明的催化剂的活性起始温度低，使用温度范围宽，可在80-180℃间有效工作。本发明的催化剂在有效工作温度区间内氧的选择性可高达80％-90％，即在有效去除一氧化碳的同时，氢气的消耗极少。     

CeO2和La2O3对混合煤在等离子体中热解的影响

研究了稀土氧化物作为催化剂对混合煤在H2 /Ar等离子体中热解过程的影响,得到了催化剂与煤的裂解程度(裂解气体收率)、裂解气体成分的关系,并且对稀土氧化物的催化裂解机理进行了讨论.     

稀土氧化物复合ZrO2陶瓷的制备及应用研究进展

稀土氧化物可作为稳定剂、烧结助剂、掺杂改性剂加入到ZrO₂陶瓷材料中,能极大地提高和改善陶瓷材料的强度、韧性,降低其烧结温度,减少生产成本.文中简要综述了稀土氧化物ZrO₂陶瓷材料的制备及应用研究状况,包括Y₂O₃复合ZrO₂陶瓷粉体、富铈稀土氧化物复合ZrO₂陶瓷粉末、Nd₂O₃复合ZrO₂陶瓷材料、Pr₂O₃\Pr₆O₁₁复合ZrO₂陶瓷、La₂O₃复合ZrO₂陶瓷、Yb₂O₃复合ZrO₂陶瓷、Sm₂O₃复合ZrO₂陶瓷材料及氧化锆中掺杂多种稀土氧化物陶瓷粉体的制备和应用,分析讨论了一些需要解决的问题,并展望了稀土复合ZrO₂陶瓷制备技术及未来研究发展趋势.      

Ln2O3/MgO催化合成增塑剂IOP的研究

采用共沉淀-焙烧法制成了LnO3／MgO(Ln=Nd，Sm，Er)担载型催化剂。该型催化剂比表面大，分散性好。在催化合成IOP中效果明显，且使Ln2O3的用量减少80％左右。     

Status of Research on Application of High Purity Rare Earth Oxides in Solid Oxide Fuel Cells

The solid oxide fuel cell (SOFC) is a high-efficient and environmentally friendly power generation system.The rare earth oxide materials are used extensively in the manufacturing of SOFC components.In particular, the CeO2doped with Gd2O3 or Sm2O3, lanthanide perovskite oxides are indispensable and key materials for developing the intermediate temperature SOFC.The research and development status of application of high purity rare earth oxides in SOFC was overviewed.The rare earth oxide-based and -doped materials were discussed for the SOFC components.Concerning the rare earth oxides applicable to SOFC, several topics were also pointed out for further researching and developing.     

Effects of rare earth oxides on dielectric properties of Y2Ti2O7 series ceramics

A series of Y2Ti2O7 microwave dielectric ceramics were synthesized by conventional solid-state method. The effects of rare earth oxide (La2O3, CeO2, Nd2O3, Sm2O3, Eu2O3, Gd2O3 and Dy2O3) and Nd2O3 doping content on the microstructure and dielectric properties of Y2Ti2O7 ceramics were investigated. The experimental results showed that the rare earth ions were considered to dissolve in Y-sites of the pyrochlore structure, different rare earth oxides and concentration had different influences on Y2Ti2O7 cerami...     

稀土钨电极研究与应用

介绍了近年对TIG(钨极惰性气体保护焊)和PLASMA(等离子体)焊接、切割用钨电极材料的研究进展和应用情况 ,着重对稀土钨电极材料及稀土氧化物作用等有关研究问题进行了讨论。对W -La2O3、W -CeO2、W -Y2O3 电极材料的热电子发射能力和稳定性研究表明 :在中小电流时2.2-wt%La2O3-W电极具有较好的电子发射能力和稳定性 ,钇钨和铈钨次之 ;在大电流工作时 ,钇钨电极热电子发射能力和稳定性最好。对制备的二元复合稀土钨电极(W -La2O3-Y2O3、W -La2O3-CeO2、W -Y2O3-CeO2)和三元稀土钨电极(W -La2O3-Y2O3-CeO2)的性能与单元稀土钨电极材料(W -La2O3、W -CeO2、W -Y2O3)和钍钨电极材料进行了比较。结果表明 ,复合稀土钨电极材料的焊接电弧性能优于单元稀土钨电极和钍钨电极。但它们的性能又各不相同 ,可适应交流焊、薄板和中厚板不同焊接工作的需求。研究表明、电极的使用性能强烈依赖于稀土金属氧化物。燃弧过程中它们的行为是影响电极使用性能、电极温度、逸出功和电极稳定性的最重要的因素。     

Catalytic Reduction of SO2 on CeO2-La2O3 Rare Earth Mixed Compounds

Adding rare earth oxide CeO2 with variable valences to La2O3 formed a mixture of rare earth oxides. By means of dipping CeO2, La2O3 and their mixture, whose carriers were all γ-Al2O3, were used as the catalyst for the reduction of SO2 by CO. The activation process of this catalyst and the impact of temperature and reactant concentration on the activation process were investigated. Using X-ray diffraction, the structure characteristics of catalyst before and after reaction were analyzed to reveal the change of phase structure. The result shows that the rare earth oxide mixtures composing of CeO2 and La2O3, as the catalyst for the reduction of SO2 by CO, diminish activation temperature 50～100℃ less and have higher activity than a single oxide CeO2 or La2O3. The reason possibl is that La2O3 goes into in the lattice of CeO2 to form solid phase complex CeO2-La2O3 and increases the capability of CeO2-La2O3/γ-Al2O3 catalyst to store oxygen, which supplies the redox of CeO2 reaction with a better condition. At the same time, elemental sulfur formed in the redox reaction impels La203 to be transformed to activation phase La2O2S in a lower temperature, which can be explained with the synergism between redox reaction and COS intermediate mechanism reaction.     

Synthesis and Thermal Decomposition Mechanism of Rare Earth Benzoates

Rareearthbenzoatesareakind0fstablecompounds.Theco0rdinationcomP0undsf0rmedbyrareearthandcarboxylicacidshaveunusualstructuresandinterestinglundnesceniProperties.Bymeansoff0rmingc0njugaedcomplexes,rareearthmetalsandcarb0xylicacidscanf0rmnetorlayerp0lymerandchangetheirlundnescentprop-erties.S0merareearthcomplexeshavebeenap-Pliedinagricultureaslight-transfeedngmaeri-al8-Althoughthermaldecompositi0nmechanismofrareearthbenz0ateshasbeenreported,itdealswith0nlys0lidphaseproducts["'1,litdeab0utgasPha…     

Effects of flaky rare earth oxide additives on the high temperature performance of nickel electrodes

Effects of flaky rare earth oxide additives including Er2O3,Tm2O3,and Yb2O3,Lu2O3 on high temperature and high rate discharge performance of nickel electrodes were investigated.The discharge efficiency at 0.2C reached 96% at 60 oC for electrodes with 1 at.% flaky rare earth oxides.The high rate discharge performance for electrodes with flaky rare earth oxides were improved significantly,for example,discharge efficiency at 5C improved from 50% to 70%.The results showed that the end charging potential of the ...     

掺杂稀土元素的高温钼合金的研究

介绍了国内外掺杂稀土元素的高温钼合金的研究情况。对Y2O3、La2O3、NdO3、Sm2O3、Gd2O3五种稀土元素掺入钼丝和未掺入钼丝了进行研究。结果表明,掺杂钼丝比未掺杂钼丝具有更高的再结晶温度和高温下更好的抗变形性能。目前这种掺有稀土元素的钼合金已被研制出,并得到广泛的应用,市场前景看好。     

Influence of Al_2O_3/CeZrAl composition on the catalytic behavior of Pd/Rh catalyst

Al2O3 and Ce-Zr mixed oxides are important components of the automobile three-way catalyst.Various contents modifying A12O3(GAL) was physically introduced into Ce-Zr-Al mixed oxides(CZA) to form series of GAL/CZA composition.The Pd/Rh catalyst samples were prepared by different GAL/CZA support loading Pd/Rh,then aged at 950 oC for 6 h.The catalytic behavior of different Pd/Rh catalyst samples was studied.Surface area,oxygen storage capacity(OSC) and H2 adsorption capacity(TPR) of fresh and aged samples were...