La_2O_3掺杂对V_2O_5-WO_3/TiO_2催化剂SCR性能的影响

通过共沉淀法将La组分掺入到TiO_2载体中,采用浸渍法将V和W组分负载到La_2O_3-TiO_2复合氧化物上,制备出V2O5-WO3/La_2O_3-TiO_2催化剂。考察不同La_2O_3掺杂量对其NH3催化还原NO性能的影响,同时通过多种物理化学手段进行表征分析。XRD,NH_3-in situ DRIFTS,H_2-TPR,XPS和UV-vis DRS测试结果表明,元素La与Ti以La-O-Ti键相互作用,生成高度分散的镧物种,也使得TiO_2具有更好的热稳定性,但由于LaO_x物种与VO_x物种和WO_x物种之间的相互作用,降低了催化剂的氧化还原性和表面Brnsted酸数量,从而降低了其催化活性。     

稀土掺杂Sr2MgSi2O7长余辉发光材料的研究进展

硅酸镁锶(Sr2MgSi2O7)作为目前常用的一种长余辉发光材料基质,性能稳定,耐酸碱性能良好。本文介绍了长余辉发光材料的发光原理,综述了近年来Sr2MgSi2O7长余辉发光材料的主要制备方法以及稀土掺杂Sr2MgSi2O7材料的研究进展,并对该材料的发展做出了展望。制备Sr2MgSi2O7长余辉发光材料的方法主要包括高温固相法,溶胶-凝胶法,化学沉淀法和燃烧合成法,其中最常用的为高温固相法。通过掺杂稀土离子可以形成具有不同发光特性的长余辉发光材料。稀土掺杂Sr2MgSi2O7材料作为一种储能、节能的长余辉发光材料,展现出了广阔的发展和应用前景。     

Physicochemical properties of a novel composite polymer electrolyte doped with vinyltrimethoxylsilane-modified nano-La2O3

Nano-La2O3 was modified with the vinyltrimethoxylsilane by hydrolysis and a novel poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) based composite polymer electrolyte doped with the modified nano-La2O3 was prepared by phase inversion method. The physicochemical properties were studied by SEM, FT-IR, XRD, TG and electrochemical methods. The results of FT-IR indicated that the nano-La2O3 was successfully modified with vinyltrimethoxylsilane. The XRD analysis showed that the incorporation of modified nano-La2O3 into the polymer electrolyte membranes could effectively reduce the crystallinity of PVDF-HFP, and the characterizations also suggested that thermal stability and electrochemical stability window could reach to 382°C and 5.1V, respectively; the reciprocal temperature dependence of ionic conductivity followed Vogel-Tamman-Fulcher (VTF) relation, ionic conductivity at room temperature was up to 3.5×10-3S/cm and lithium ions transference number was up to 0.42; the interfacial resistance increased at initial value about353Ω/cm2 and reached a steady value about 559Ω/cm2 after 5d storage at 30°C. The fabricated Li/As-prepared electrolytes/LiCoO2 coin cell showed excellent rate and cycle performances.     

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.      

Photocatalytic activity of cerium-doped mesoporous TiO2 coated Fe3O4 magnetic composite under UV and visible light

A novel kind of magnetically separable photocatalyst of cerrium-doped mesoporous titanium dioxide coated magnetite (Ce/MTiO2/ Fe3O4) was prepared and its activities under UV and visible light were reported. The catalysts with Ce/MTiO2 shell and Fe3O4 core were pre-pared by coating photoactive Ce/MTiO2 onto a magnetic Fe3O4 core through the hydrolysis of tetrabutyltitanate (Ti(OBu)4, TBT) with pre-cursors of ammonium ceric nitrate and TBT in the presence of Fe3O4 particles. The MTiO2 shell was for photocatalysis, the Fe3O4 core was for separation by the magnetic field and the doped Ce was used to enhance the photocatalytic activity of MTiO2. The morphological, struc-tural and optical properties of the prepared samples were characterized by Brunauer-Emmett-Teller (BET) surface area, transmission electron microscopy (TEM), X-ray diffraction (XRD) and UV-vis absorption spectroscopy. The effect of cerrium-doped content on the photocatalytic activity was studied and the result revealed that 0.5 mol.% Ce/MTiO2/Fe3O4 exhibited highest photoactivity. The photocatalytic activities of obtained photocatalysts under UV and visible light were estimated by measuring the degradation rate of methylene blue (MB, 50 mg/L) in an aqueous solution. The results showed that the prepared photocatalyst was activated by visible light and used as effective catalyst in photooxi-dation reactions. In addition, the possibility of cyclic usage of the prepared photocatalyst was also confirmed. Moreover, Ce/MTiO2 was tightly bound to Fe3O4 and could be easily recovered from the medium by an external magnetic filed. So, the photocatalyst can be reused without any mass loss. It can therefore be potentially applied for the treatment of water contaminated by organic pollutants.     

Removal of Cooking Fume by Catalytic Combustion on Pt/La-Al2O3 ＋ Ce0.5 Zr0.5O2 Catalyst

Four monolithic catalysts with low concentration of noble metal were prepared by the immersion method [ Pt/La- Al2O3, Pt/La-Al2O3 ＋ Pt/OSM （2 ： 1 ）, Pt/La-Al2O3 ＋ Pt/OSM （ 1 ： 1 ） Pt/La-Al2O3 ＋ Pt/OSM （ 1 ： 2） ], and measurements of their activity were carded out in a conventional fixed-bed flow reactor. The results show that the oxygen storage material （OSM） that is added can promote the activity of the prepared catalysts and can decrease the complete conversion temperature of cooking fume. When the ratio between La-Al2O3 and OSM is 1 ： 1, the catalyst has the highest activity, and the complete conversion temperature of cooking fume is 270℃ ; the catalyst thus prepared can be applied in a wide range of gas hourly space velocity （GHSV） [from 10000 to 60000 h^-1]. The catalyst obtained shows great potential for practical application.     

稀土掺杂锂离子电池正极材料LiCoO2的影响研究

在合成LiCoO₂的基础上, 采用共沉淀法掺杂稀土La、Ce、Lu、Y等合成制备了LiRE_xCo_1-xO₂, 并对其进行了XRD、SEM表征及电性能测试。结果表明, 合成的LiRE_xCo_1-xO₂具有LiCoO₂结构, 当稀土La的加入量x < 0.05时, 稀土能完全形成单一LiRE_xCo_1-xO₂相; 稀土的掺入能促进LiCoO₂结晶, 同时使104面的相对衍射强度增加; LiRE_xCo_1-xO₂首次放电容量达147.4mA·h/g, 循环稳定性有所提高。      

Effects of La2O3/Li2O/TiO2- Coating on Electrochemical Performance of LiCoO2 Cathode

Conventional cathode material （LiCoO2） was modified by coating with a thin layer of La2O3/Li2O/TiO2 for improving its performance for lithium ion battery. The morphology and structure of the modified cathode material was characterized by SEM, XRD, and Auger electron spectroscopy. The performance of the cells with the modified cathode material was examined, including the cycling stability, the diffusion coefficient under different voltages, and the C-rate discharge. The results showed that the cell composed of the coated cathode material discharged at a large current density, and possesses a stable cycle performance in the range from 3.0 to 4.4 V. It was explained that the rate of Li ion diffusion increased in the cell while using La2O3/Li2O/TiO2-coated LiCoO2 as the cathode and the coating layer may act as a faster ion conductor （La2O3/Li2O/TiO2）.     

稀土复合固体超强酸SO42-/ZrO2- 2% Gd2O3催化合成乙酸戊酯

制备了稀土复合固体超强酸SO₄2-/ZrO_2- 2%Gd₂O₃催化剂,并对以乙酸和戊醇为原料合成乙酸戊酯的反应条件进行了研究。研究表明:当戊醇与乙酸的摩尔比为1:1.5,反应时间为6h,反应温度为130℃,催化剂用量为6%戊醇的质量时,反应酯化率最高,酯化率可达98.93%,选择性高达100%。研究发现,该催化剂可重复使用,并能活化再生。      

化学包覆法制备TiO_2/SiO_2复合物

与TiO2光催化剂相比,以SiO2为载体或内核制备的TiO2/SiO2复合催化剂,其表面活性、光催化活性和热稳定性都更高。以粉煤灰为原料制备的沉淀SiO2为硅源,钛酸四丁酯为钛源,采用化学包覆法制备TiO2/SiO2复合物,采用扫描电镜(XRD)、红外光谱(FT-IR)和差热分析(TG-DTA)等测试手段对该复合物进行表征。FT-IR和TG-DTA分析证实,SiO2被TiO2有效包覆。复合物热稳定性较高,经700℃焙烧4 h后,SiO2仍为无定形,TiO2以锐钛矿相为主;在900℃焙烧后,TiO2大部分由锐钛矿相转变为金红石相。     

新型CeO2-Fe2O3联合催化剂用于催化CO还原NO

采用3种不同的方法合成新型的以Fe₂O₃颗粒为载体的Ce-Fe复合氧化物催化剂,探究不同制备方式的复合氧化物催化剂的催化CO还原NO性能,并通过X射线衍射(XRD)、拉曼光谱(Raman)、氢气-程序升温还原(H2-TPR)、X射线光电子能谱(XPS)表征来对催化剂进行探究。结果证明Ce-Fe复合氧化物具有较高的催化活性,硝酸水热法Ce-Fe复合氧化物在900℃时脱硝率可达到99%以上。XRD中显示硝酸水热样品中CeO₂峰向高角度偏移,并且晶格常数变小。Raman结果说明硝酸水热样品CeO₂的振动峰向左大幅度偏移,结合XRD说明硝酸水热法可以形成Ce-O-Fe固溶体。H2-TPR说明氧化还原性:硝酸水热法>硝酸浸渍法>普通浸渍法。XPS结果说明硝酸水热法形成的Ce-O-Fe固溶体可以促进Fe³⁺向Fe²⁺、晶格氧向吸附氧的转换,这体现出复合催化剂Ce、Fe之间的联合作用。在整个反应过程中Fe₂O₃作为载体可以提供大量晶格氧,Ce-O-Fe固溶体的存在决定了复合催化剂的高催化活性。     

CeO2/Bi2MoO6纳米复合材料的制备及 其增强光催化降解性能研究

采用水热法制备了一系列不同的CeO₂/Bi₂MoO₆纳米复合材料,分别考察了pH值（2~9）和Ce/Bi摩尔比（3 %~10 %）等因素对其光催化性能的影响.利用X射线粉末衍射、扫描电镜、红外光谱、紫外-可见漫反射光谱、光致发光光谱、瞬态光电流-时间响应等一系列分析测试手段对催化剂的组成、结构、光电性能等进行表征.结果表明,当pH=6时,所制备的Bi₂MoO₆（BMO）晶体形貌为细针状,复合CeO₂后形貌为厚片状,比表面积减小、晶体颗粒增大.在实验室模拟太阳光条件下（300 W氙灯)进行光催化活性测试,分别以罗丹明B（RhB）、亚甲基蓝（MB）和苯酚为模拟污染物,对复合光催化剂的光催化活性进行考察,结果表明,当CeO₂的含量为5 %时呈现出最高的光催化降解活性. 5 % CeO₂/BMO对RhB、MB和苯酚的光催化反应的速率常数分别为0.037 min-1、0.016 min-1和0.007 min-1,相对于纯的BMO分别提高了3.19倍、1.70倍和4.58倍.其光催化性能增强主要原因是CeO₂与Bi₂MoO₆复合后形成异质结有利于光生电子-空穴的有效分离,从而提高了活性自由基的含量.在自由基捕获实验中,超氧根离子自由基（·O2-）、羟基自由基（·OH）和空穴（h+）参与了光催化降解,其影响顺序为:·O2->·OH>h+.      

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。     

Rare earth oxide modified Cu-Mn compounds supported on TiO₂ catalysts for low temperature selective catalytic oxidation of ammonia and in lean oxygen

Selective catalytic oxidation(SCO) of ammonia was carried out over Cu-Mn compounds catalysts modified with trivalent rare earth oxide Ce2O3 and La2O3 respectively.TiO2 was used as support and different ratio of O2 were tested in order to find an appropriate O2 concentration(vol.%),and the results showed that 1%O2(vol.%) was propitious to SCO of ammonia.The effects of the two rare earth oxides modified catalysts Ce2O3-Cu-Mn/TiO2 and La2O3-Cu-Mn/TiO2 on the catalytic activity and selectivity of ammonia oxidation were investigated under the reaction condition of 500 ppm ammonia,1%O2(vol.%),at the temperature from 125 to 250 oC.The results revealed the beneficial role of Ce2O3 and La2O3 in catalytic activity at low temperature and lean oxygen concentration,while the modification with Ce2O3 and La2O3 led to the negative influence on N2 selectivity.For the catalysts modified with Ce showed lower NO and N2O selectivity than the catalysts modified with La,then the effects of different Ce loadings on catalytic activity and selectivity were also considered,in combination with catalysts preparation methods,which include incipient wet impregnation,sol-gel method and co-precipitation.Results revealed that the catalysts prepared by sol-gel method obtained preferable catalytic activity compared with the others,reaching 99% ammonia at 200 oC,whereas 96% NO was detected.It also indicated that different catalyst preparation method significantly determined production distribution.     

Effects of Mineral Tourmaline Particles on Photocatalytic Activities of RE/TiO2 Composite Thin Films

The composite TiO2 films containing the mineral tourmaline particles and rare earth elements (T/RE/TiO2 )were prepared by a sol-gel method using Ti( OC4H9 )4 as raw material. The microstructure and forming mechanism of T/RE/TiO2 films were studied by scanning electron microscope (SEM). Effects of tourmaline on the photocatalytic activities of RE/TiO2 were determined by photocatalytic degradation of formaldehyde. The results show that the photocatalytic degradation ratio of formaldehyde increases by 44.2% with the composite films of Ce/TiO2 containing 0.04%tourmaline, more than that with the thin films of Ce/TiO2 under UV irradiation.     

纳米TiO2负载钯催化剂的性能研究

采用浸渍法制备了纳米TiO2负载钯催化剂,以乙炔选择催化加氢制备乙烯为反应模型考察了稀土元素La、空速对纳米Pd／TiO2催化剂性能的影响,并与纳米SiO2为载体的Pd—La／SiO2催化剂的性能做了比较。实验结果表明,纳米Pd／TiO2催化剂具有良好的催化活性和性能稳定性,La的加入显著提高了乙烯的选择性、增幅达加％左右。与Pd—La／SiO2催化剂相比,Pd—La／TiO2催化剂具有更高的选择性。     

固体超强酸S_2O_8~(2-)/TiO_2-WO_3的制备及其催化性能研究

用溶胶-凝胶法制备了固体超强酸S2O82-/TiO2-WO3,并对其进行了XRD与IR表征,用乙酸乙酯合成模型反应考察了其催化性能,系统研究了WO3的含量、焙烧温度等制备条件对S2O82-/TiO2-WO3性能的影响。实验表明:在(NH4)10W12O41.xH2O质量分数为5.0%、焙烧温度为500℃条件下通过溶胶-凝胶法制备的固体超强酸S2O82-/TiO2-WO3,其载体为微细且晶格不太完整的锐钛矿型TiO2,比表面积较大,具有比浸渍法制备的SO42-/TiO2更高的硫含量和更强酸性,并具有较高的催化酯化活性和稳定性,在反应条件为:醇酸摩尔比1.48∶1、催化剂用量为冰醋酸的6.0%、反应时间2.0h,乙酸转化率可达74.1%(不加分水器)。催化剂在无需任何再生的条件下重复使用,活性下降趋势平缓,显示良好的稳定性。     

稀土固体超强酸催化剂S2O82-/ZrO2-SiO2-Sm2O3的制备

采用沉淀-浸渍法制备了负载稀土的固体超强酸S2O82-/ZrO2-SiO2催化剂,以乙酸丁酯的合成为探针反应进行了单因素测试,考察了制备条件对催化剂性能的影响.结果表明,载入不同稀土金属氧化物、不同硅锆原子量比以及预焙烧温度、焙烧温度和浸渍液浓度等因素对催化活性有显著影响.     

Promotional effect of CeO2 and Y2O3 on CuO/ZrO2 catalysts for methane combustion

Catalytic combustion of methane was conducted by using a Cu-based catalyst prepared by the plasma-assisted impregnation method. The properties of the catalysts were surveyed by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and temperature-programmed reduction (H2-TPR). The results showed that the activity of CuO/ZrO2 with the CeO2 and Y2O3 was obviously increased compared with the CuO/ZrO2 catalyst, which was examined in relation to the structure and surface characteristics and might be correlated with their surface oxygen species and redox properties. Among the investigated catalysts, the Ce-CuO/ZrO2 sample exhibited the highest activity for methane combustion.     

水热法合成Ag2CO3/ZnO异质结复合光催化剂及其光催化性能

采用水热法合成了一系列不同Ag₂CO₃含量的新型Ag₂CO₃/ZnO异质结复合光催化剂, 运用X射线粉末衍射(XRD)、扫描电镜(SEM)、X射线光电子能谱(XPS)、傅里叶变换红外光谱(FT-IR)、紫外-可见漫反射吸收光谱(UV-vis DRS)等系列手段对所制备的光催化剂进行了表征, 并以紫外光(254 nm)为光源, 评价了催化剂光催化降解甲基橙的活性, 考察了不同Ag₂CO₃复合量、不同水热温度对ZnO复合光催化剂反应活性的影响.结果表明, 当Ag₂CO₃含量为2 %、水热温度为140 ℃, 复合光催化剂具有最大的光催化活性, 降解率达到86.31 %.Ag₂CO₃/ZnO异质结复合光催化剂具有更高的光催化活性主要原因是复合光催化剂对紫外光有很强的吸收能力, 适量Ag₂CO₃能提高光生电子-空穴对的分离效率, 并改善催化剂的物理性能.