LaF3及LaF3(掺杂)固体电解质的特性及其应用

对LaF3及LaF3(掺杂)作为固体电解质的导电能力和特性进行了分析。讨论了掺杂对LaF3导电性的影响。介绍了LaF3及LaF3(掺杂)单晶固体电解质在室温水溶液中氟离子选择电极、多晶固体电解质在高温熔体中镧传感器、以及各类气体传感器中的应用。     

常温下SO2气体传感器的研究

以LaF3(掺杂CaF2)的单晶片为固体电解质,Na2SO3、Na2O为参比电极,含SO2的空气为待测电极构成敏感浓差电池.利用此电池在299～319 K温度范围,用不同SO2含量的空气作待测电极的情况下,进行了电动势测量.实验发现,电池的响应时间在5 min之内;在特定的温度下,电池的电动势E与SO2分压的对数成正比,符合能斯特公式.通过对电池阻抗谱的测量与研究,发现在温度较低的条件下,LaF3单晶片具有较高的离子电导率,适于作为低温气体敏感浓差电池的固体电解质材料.     

白光LED用LaF_3:Eu~(3+)红色荧光粉的制备与表征

采用水热法制备具有单一相六方晶系的LaF_3:Eu~(3+)纳米荧光粉.通过X射线粉末衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)、光致发光光谱(PL)和荧光衰减曲线对LaF_3:Eu~(3+)纳米荧光粉进行表征. LaF_3:Eu~(3+)荧光粉的激发光谱主要由250 nm处的宽带(O2-→Eu3+的电荷转移跃迁)和一些尖峰(Eu3+f-f跃迁)构成,其中位于近紫外区396 nm处有一较强的激发峰.通过发射光谱探测Eu3+在LaF3晶体中的局部晶场环境.在298 K下激发光谱和发射光谱可知,在六方晶系的LaF3纳米晶体中的Eu3+晶格位置从D4h降至到C2v,这是由于晶格变化所造成的.在396 nm激发下,观测到较优掺杂浓度为10%的LaF_3:Eu~(3+)荧光粉在591 nm(5D0→7F1跃迁)处有强烈的红色发射峰.其发光性能表明,LaF_3:Eu~(3+)红色荧光粉在近紫外发光二极管领域具有潜在的应用价值.     

铁液中硫活度的测定方法探讨

以CaS(1%Y2S3)作固体电解质,W/WS2为参比电极组成化学传感器,对碳饱和铁液中硫的活度进行了测定,实验证明:CaS(1%Y2S3)固体电解质作为定硫传感器是可行的.     

BaCeO3和SrCeO3基钙钛矿型固体电解质

综述了BaCeO₃基和SrCeO₃基钙铁矿型固体电解质.从结构、不同气氛中导电性方面进行了介绍,对其应用方面进行了较为详细的分析.在燃料电池、电解池、薄膜反应器、气体传感器等方面的应用分析表明这2类固体电解质有广泛的应用前景.     

Al2O3的掺杂浓度对Ce0．8Y0．2O1．9电解质的性能影响研究

利用低温燃烧合成法制备了Al2O3掺杂浓度为0.5%～10%(摩尔分数,以下同)的Al2O3/Ce0.8Y0.2O1.9固体电解质复合材料。研究了Al2O3掺杂浓度对Ce0.8Y0.2O1.9固体电解质烧结及电性能的影响。试验结果表明,添加少量的Al2O3可以改善Ce0.8Y0.2O1.9固体电解质的烧结性能,当Al2O3的添加量为0.5%时,电解质粉体具有最佳的烧结性能,1350℃时的相对密度达到99%以上。当Al2O3的掺杂浓度超过其在Ce0.8Y0.2O1.9中的溶解极限时,随Al2O3掺杂量的继续增加,烧结体的相对密度开始下降。阻抗谱结果表明,在溶解极限范围内,Al2O3使Ce0.8Y0.2O1.9的电导率减小,电导活化能增加。Al2O3的掺杂浓度超过溶解极限时,Ce0.8Y0.2O1.9的晶粒电阻不变,由于Al2O3对晶界的"清洁"作用,晶界电阻减小;当Al2O3的掺杂浓度超过5%时,由于Al2O3颗粒对晶界的"阻塞"作用,晶界电阻增加。     

固体氧化物燃料电池中的电解质

综述了固体氧化物燃料电池（SOFC）中固体电解质的研究概况,分析了ZrO2基、CeO2基、Bi2O3基固体电解质和掺杂的LaGaO3为代表的钙钛矿结构的固体电解质的优缺点以及作为SOFC电解质存在的问题,中低温度下稳定的高离子电导率的固体电解质的研制开发及固体电解质的薄膜化研究是降低S0FC工作温度的两个重要途径。     

Ti~(4+)掺杂对Na-β"-Al_2O_3固体电解质电性能的影响

Na-β"-Al2O3固体电解质材料的Na+电导率直接影响着钠硫电池的性能。以提高Na-β"-Al2O3固体电解质材料Na+电导率为目的,利用传统固相反应法,在Li+掺杂作为稳定剂的基础上,加入0%～1. 25%(质量分数)TiO2引入Ti4+,制备Na-β"-Al2O3固体电解质材料。采用X射线衍射(XRD)以及扫描电子显微镜(SEM)对样品进行表征,采用交流阻抗法测试了样品的电导率。实验结果表明,Ti4+掺杂可较大幅度提高Na-β"-Al2O3材料的Na+电导率,原因有三:一是Ti4+掺杂进入Na-β"-Al2O3晶格取代了Al3+,掺杂后抑制了β"相向β相的转变,从而提高β"相的相对含量,且无杂相生成;二是Ti4+掺杂可以降低材料的烧结温度,促进晶粒生长,从而提高了材料的体积密度;三是Ti4+掺杂可以降低材料在高温烧结过程中钠组分的挥发,提高材料的钠含量。其中,在TiO2掺杂量为0. 75%,烧成温度为1575℃,保温0. 5 h条件下,制得的材料性能最佳,电导活化能为0. 1606 eV,离子电导率由未掺杂样品的0. 023 S·cm-1提升至0. 034 S·cm-1。     

CeO_2基固体氧化物燃料电池电解质研究

固体氧化物燃料电池(SOFCs)被誉为21世纪最具有发展潜力的能源技术之一.由于用稀土或碱土金属氧化物掺杂的CeO2在较低的温度下具有较高的氧离子电导率,是用作中低温固体氧化物燃料电池较理想的电解质材料.本文综述了近年来以掺杂的CeO2作电解质的SOFCs性能的研究情况,总结了提高、改善CeO2基固体电解质电性能的几种方法,并对今后的研究提出了自己的看法.     

CeO2基固体电解质材料研究进展

稀土或碱土氧化物掺杂铈基电解质在中低温下具有高的离子电导率,被认为是一种很有前途的电解质材料.本文主要对各种掺杂铈基电解质材料研究及在固体氧化物中的应用进行了综述.对掺杂铈基电解质的制备方法进行简单介绍.     

Preparation and Luminescence of Er^3＋ Doped Oxyfluoride Glass Ceramics Containing LaF3 Nanocrystals

Er^3＋ doped transparent oxyfluoride glass ceramics version and near infrared luminescence behavior of Er^3＋ in containing LaF3 nanocrystals were prepared and the up-conglasses heat-treating time and temperature, the size （varied from 0 to 19 and glass ceramics were investigated. With increasing nm） and crystallinity （varied from 0 to 47%） of LaF3 nanocrystals in the glass ceramics are increased. The up-conversion luminescence intensity of Er^3＋ ions in the glass ceramics is much stronger than that in the glasses The near infrared emission of Er^3＋ ions in and increased significantly with increasing heat-treating time and temperature the glass ceramics is found to be similar to that in the glasses.     

Spectroscopy of Pr^3＋4f5d Configuration in LaF3 Nanocrystals／Oxyfluoride Glass Ceramics

Theinterestofinvestigatingthe 4fn -15delectronicconfigurationofthetrivalentrareearth (RE)ionsisbasedonavarietyofapplicationsinthevacuumultra violet (VUV)regionofthespectrum ,suchasthede velopmentofplasmadisplaypanelsandmercury freefluorescenttubes[1] .Amo…     

LaF3纳米微粒的摩擦学行为研究

本文在醇－水体系中采用共沉淀表面修饰法制备了磷酸烷基酯修饰的ＬａＦ３纳米微粒。利用多种分析手段表征了表面修饰ＬａＦ３纳米微粒的结构和润滑性能,结果表明形成了以ＬａＦ３为纳米核、有机磷化合物为表面修饰层在有机溶剂中具有良好分散性的ＬａＦ３纳米微粒,作为润滑油添加剂,具有良好的减摩、抗磨和承载性能。     

Photoluminescence properties of LaF3：Eu^3＋ nanoparticles prepared by refluxing method

The europium-doped LaF3 nanoparticles were prepared by refluxing method in glycerol/water mixture and characterized with X-ray diffraction(XRD), field emission scanning electron microscopy(FE-SEM), UV-vis diffuse reflectance spectrum, and photoluminescence spectra. The results of XRD indicated that the obtained LaF3: Eu3+ nanoparticles were well crystallized with a hexagonal structure. The FE-SEM image illustrated that the LaF3: Eu3+ nanoparticles were spherical with an average size around 30 nm. Under irradiation of UV light, the emission spectrum of LaF3: Eu3+ nanoparticles exhibited the characteristic line emissions arising from the 5D0→7FJ (J=1, 2, 3, 4) transitions of the Eu3+ ions, with the dominating emission centered at 590 nm. In addition, the emissions from the 5D1 level could be clearly observed due to the low phonon energies (-350 cm-1) of LaF3 matrix. The optimum doping concentration for LaF3: Eu3+ nanoparticles was determined to be 20mol.%.     

Synthesis and Upconversion Luminescence of LaF3 ： Yb^3＋ , Er^＋/SiO2 Core/Shell Microcrystals

LaF3：Yb^3＋ , Er^＋ microcrystals were synthesized by a hydrothermal method, and then, the LaF3： Yb^3＋ , Er^＋ microcrystals were coated with silica. Phase identification of LaF3： Yb^3＋ , Er^＋ and LaF3： Yb^3＋ , Er^＋/SiO2 was performed via XRD. The TEM image showed that the size of LaF3： Yb^3＋ , Er^＋ was 150 nm and LaF3： Yb^3＋ , Er^＋/SiO2 presented clearly a core/shell structure with 20 nm shell thickness. The upconversion spectra of LaF3： Yb^3＋ , Er^＋ and LaF3： Yb^3＋ , Er^＋/SiO2 in solid state and in ethanol were studied with a 980 nm diode laser as the excitation source. The upconversion spectra showed that the silica shell had little effect on the properties of fluorescence of the LaF3：Yb^3＋ , Er^＋ microcrystals. At the same time, the green luminescence photo of LaF3： Yb3＋, Er3＋/SiO2 in the PBS buffer was obtained, which indicated that the LaF3： Yb^3＋ , Er^＋/SiO2 could be used in biological applications.     

Tb3+掺杂复合材料LaF3-SiO2的制备和发光性能研究

采用溶胶-凝胶法在室温条件下制备了掺杂Tb3+的复合材料LaF3 -SiO2,通过XRD、TG-DTA、IR、激发和发射光谱研究了材料的结构和发光性能.结构表测试表明,在高于494℃时LaF3-SiO2:Tb3+转变为稳定的氟铈矿六方结构,800℃退火处理后,材料主要存在Si-O-Si键;发光性能研究表明,最佳退火温度为800℃;样品在544nm监测波长下,最佳激发波长为228nm,Tb3+的最佳掺杂摩尔浓度为0.48％.     

Synthesis and photoluminescent properties of Eu~(3+)/Dy~(3+) doped SrO-Al_2O_3-SiO_2 glass-ceramics

Eu~(3+)/Dy~(3+) single-doped and co-doped 6SrO-3Al_2O_3-91SiO_2 and 12SrO-6Al_2O_3-82SiO_2 glass and glass-ceramics were synthesized successfully by a sol-gel method. The prepared samples were characterized by the X-ray diffraction, high-resolution transmission electron microscopy, photoluminescent spectra and X-ray photoelectron spectroscopy. The effect of annealing temperature, doped ions and matrix component on the structure and the photoluminescent characteristics was systematically studied. The higher temperature was helpful to form nanocrystals and the amount of SrO and Al_2O_3 could better disperse the rare earth ions in matrix at suitable temperature, and both of them could improve the luminescent intensity. Meanwhile, the doped ions could change the luminescent color by single, codoped and energy transfer. The Sr_2SiO_4 nanocrystals were observed in silicates glasses and became larger with the increase of the annealing temperature and the luminous efficiency of rare-earth(RE) ions could be enhanced when the samples changed from glass state to glass-ceramic state. The results indicated that the photoluminescent properties could be changed through controlling the doped ions, annealing temperature and matrix component.     

CuTa_2O_6掺杂Ba(Zn_(1/3)Ta_(2/3))O_3基微波陶瓷烧结动力学及微波性能

结合烧结动力学模型和微观形貌观察,研究未掺杂和掺杂CuTa_2O_6的Ba(Zn_(1/3)Ta_(2/3))O_3陶瓷在1 270~1 520℃温度范围内的致密化过程和烧结动力学机理。结果表明:在1 150℃以上烧结,随温度升高,Ba(Zn_(1/3)Ta_(2/3))O_3的烧结机制从体积扩散向晶界扩散转变。掺杂0.25%CuTa_2O_6可显著加快Ba(Zn_(1/3)Ta_(2/3))O_3陶瓷的烧结致密化过程,在显著降低烧结温度的同时,可大幅缩短烧结时间并有效地促进B位的有序化。掺杂Ba(Zn_(1/3)Ta_(2/3))O_3陶瓷在1370℃烧结12h即可获得96%的相对密度,在1 370℃烧结12 h后的介电常数(εr)和品质因数(Q·f)分别约为29.4和985 35;相比较,未掺杂Ba(Zn_(1/3)Ta_(2/3))O_3在1 520℃烧结12 h的εr和Q·f分别只有27.4和68 147。掺杂Ba(Zn_(1/3)Ta_(2/3))O_3陶瓷经1 520℃烧结48 h的εr和Q·f分别约为28.2和103 131。     

Fe2O3、Cr2O3掺杂对4YSZ导电性能的影响

用柠檬酸溶胶-凝胶法制备了分别掺Fe2O3和Cr2O3的4YSZ前驱体凝胶,凝胶在500℃预烧,压制成圆片状后在1 300℃煅烧2 h得到所需试样;分别研究Fe2O3、Cr2O3的不同掺量对试样的烧结性能、电导率的影响。结果表明掺Fe2O3可提高试样的电导率和烧结性能;掺Cr2O3可提高试样的低温电导率,但使试样的烧结性能下降。     

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。