氮离子和稀土离子共掺杂纳米TiO2光催化性能的研究

以钛酸丁酯为原料,以尿素和稀土离子的硝酸盐溶液为掺杂物质,用溶胶．凝胶法制备了氮离子和稀土离子共掺杂的纳米TiO2样品。采用TEM,BET,UV．VIS等方法对样品进行了表征,通过可见光下降解硝基苯对样品的光催化活性进行了研究。结果表明,氮和稀土离子（Y,Nd）共掺杂可增大光催化剂的光吸收范围,并提高其催化活性;当N,Y和Nd离子以7％,2．0％和1．5％（摩尔分数）共掺杂时,制备的样品具有最佳的光催化性能。     

银纳米晶对铒镱共掺的TeO2-WO3-La2O3微晶玻璃发光性能的影响

通过熔融退火的方法以及热处理技术制备得到含有Er₂WO₆,La₂WO₆晶体的TeO₂-WO₃-La₂O₃-Er₂O₃-Yb₂O₃微晶玻璃,该玻璃具有优异的上转换发光性能。结果表明,在含银纳米晶的碲酸盐微晶玻璃中,银纳米晶和微晶的析出情况与银纳米晶的引入方式和热处理温度有关。经过390℃下15 min的热处理后,AgCl和AgNO₃共掺的碲酸盐微晶玻璃比单掺AgCl或AgNO₃的碲酸盐微晶玻璃具有更高的发光强度。银纳米晶与微晶的引入可协同提高碲酸盐玻璃的上转换发光性。     

聚酰胺-胺树状高分子与稀土离子络合的荧光光谱研究

合成了4.0代聚酰胺-胺(PAMAM)树状分子,用荧光分光光度法研究了4.0代PAMAM树状分子与Sm3 、Dy3 、Ce3 的络合作用.结果表明,反应时间、PAMAM物质的量、反应体系pH都会影响PAMAM对Ce(Ⅲ)、Sm(Ⅲ)及Dy(Ⅲ)离子的配位作用,对端氨基树状高分子主要存在RE-N4和RE-N2两种配位方式;随着稀土离子的加入,各种配位方式的相对比例会发生变化;pH对配位方式也有较大的影响.该研究为制备尺寸可控的PAMAM树状高分子封闭的稀土原子簇提供了理论基础.     

表面对纳米微粒中稀土离子光谱性质的影响

对于稀土和过渡金属这样的离子中心,由于电子轨道的半径小，纳米尺度的限域对能级位置和跃迁速率的影响并不显著，表面效应成为这类材料与相应体材料光谱性质出现差异的主要因素。把使稀土离子光谱性质产生可测量变化的环境用一个以其为中心、半径为D的作用球表示，可以定义纳米材料厚度为D的表面层。用完整晶格的晶体场和一个补偿电荷的场近似描述表面层中稀土离子的晶体场。本文用这个模型分析了纳米微粒中稀土离子光谱的非均匀宽化，激光选择激发下发射光谱随激发波长的变化，非选择激发下发射光谱随温度的变化以及跃迁分支比的变化等实验现象。     

稀土穴状荧光配合物的合成与光谱性质

以2,6-二甲基吡啶-3,5-二甲酸二乙酯为起始原料,经N-溴代丁二酰亚胺(NBS)溴代、亲电取代反应合成了时间分辨荧光免疫分析双功能螯合剂2,6-{N,N′,N,N′-[二(2,2′-联吡啶-6,6′-二甲基)]二(氨甲基)}-吡啶-3,5-二羧酸二乙酯。经差热分析仪(DTA)、傅里叶变换红外光谱仪(FTIR)、核磁共振波谱仪(1 H NMR)、质谱仪(MS)等技术手段表征确认了化合物结构和性能。对该化合物与铕离子形成螯合物的荧光性质研究表明:激发光谱波长范围较宽,激发峰值为322nm;荧光发射峰为597nm(~5D_0-~7F_1)、618nm(~5D_0-~7F_2);荧光寿命为918μs;量子产率Φ=0.249。     

Ce3+和Tb3+掺杂的稀土硼酸盐玻璃的发光性质

报道Ｃｅ＾３＋和Ｔｂ＾３＋掺杂的硼酸盐玻璃的合成及该系列玻璃的激发和发射光谱性质。在紫外光激发下,玻璃中的Ｃｅ＾３＋发射蓝紫光,Ｔｂ＾３＋发射有特征的绿光,在Ｃｅ＾３＋和Ｔｂ＾３＋共掺杂的体系中,可观察到Ｃｅ＾３＋强烈敏化Ｔｂ＾３＋发光的现象。分析表明,Ｃｅ＾３＋和Ｔｂ＾３＋之间存在辐射能量传递稿铲无辐射能量传递。     

稀土元素对提铯离子筛交换性能的影响

对比了提铯离子筛对铯离子与分部稀土元素的交换容量和分配系数;了钕离子对提铯离子交换性能的影响,以及稀土元素存在对提铯离子筛在高效废液中选择性的影响。稀土元素对提铯离子筛的铯离子交换容量有一定的影响,但对铯离子分配系数影响不大;只要选择合适的液固比V：m,基本上可以消除稀土元素的存在对提铯离子筛在高放废液中铯离子选择性的影响。     

Paramagnetic Centres in Irradiated Ultraphosphate Glasses Containing Rare Earth Elements

Abstract

In this study three-component ultraphosphate glasses based on Nd, Gd, Ce penta-phosphates were investigated by the EPR method depending on their synthesis conditions. EPR spectra were recorded using a “Radiopan” (Poland) radiospectrometer with a-c-field frequency 9 GHz and modulation frequency 100 kXz at 77 K. The samples were irradiated at γ-⁶⁰Co source. EPR spectra of unirradiated ultraphosphate glasses synthesized in oxidizing conditions exhibit at broad nonstructural line with ΔH_1/2 = 100 mT which, probably, can be considered as a Gd³⁺ ion cluster. After gamma-irradiation no additive PMC (except nydrogen atoms) arise in these glasses. EPR spectra of nonirradiated glasses synthesized in reductive conditions do not exhibit paramagnetic centres. 4 types of PMC appear in EPR spectra after irradiation: hydrogen atoms doublet with A iso = 50 mT, anisotropic doublet with A_I = 3.7 mT, A_II = 4.6 mT and g_II = 2.004, g_I = 2.018 which was earlier considered as a phosphor-acid radical PO^2- ₄, and two doublets with A¹ _I = 75 mT, A¹ _II = 90 mT, g¹ _I = 2.036, g¹ _II = 2.033, and A² _I = 105 mT, A² _II = 150 mT and g² _I = 2.082, g² _II = 2.077, which can be considered as a hole PMC PO^2- ₃ in different environment. The maximum concentration of these centres does not exceed 10^l5 (absorbed dose 600 kGy/h), and the ratio changes according to glass synthesizing temperature. Thus, ultraphosphate glasses synthesized in oxidizing conditions have a big paramagnetic radiation stability in comparison to analogous glasses synthesized in reductive conditions.     

稀土对WC颗粒增强铁基体复合涂层组织结构的影响

采用氩弧熔覆技术在45号钢表面制备一层稀土WC颗粒增强铁基体耐磨复合涂层。通过扫描电镜(SEM)、X射线衍射(XRD)和能谱仪(EDS)等测试分析手段研究了稀土的引入对复合涂层中基体组织及碳化物的影响,并与未加稀土进行了比较。结果表明:引入稀土后,一方面优化了熔覆层组织中碳化物颗粒分布,降低了熔覆层组织中碳化物颗粒的团聚、桥接,且颗粒分布均匀;另一方面改善了熔覆层的组织,细化晶粒,减弱了熔覆过程中产生的树状晶,抑制了WC颗粒的溶解和鱼骨状碳化物的生成。在熔覆层组织中碳化物颗粒相主要有三种存在形式:原始未熔WC颗粒、与基体形成的复式碳化物及在凝固过程中重新结晶的W2C(或WC)。     

稀土对Keggin结构磷钼酸催化剂结构和性能的影响

合成了具有Keggin结构的杂多酸催化剂。选用稀土元素La、Ce、Pr对催化剂进行掺杂,考察了添加稀土前后的结构、热性能以及对异丁酸的吸附情况,讨论了稀土的添加对催化剂结构和性能的影响。     

Silica Gels and Gel Glasses Containing Silver and Platinum Metal Particles

Silica gels containing between 0.05 and 20.0 mol% Ag2O and between 0.1 and 1.0 mol% PtO2 have been synthesized using TEOS, C2H5OH, H2O, HNO3, HCl, AgNO3 and PtCl4 as precursors. The gels obtained with Ag2O are colorless, while the gels containing PtO2 are yellow. The gels have been heat treated in the 25–1000°C temperature range. The processes of structural evolution of gels have been studied by means of IR-spectroscopy, X-ray diffraction analysis, transmission electron microscopy (TEM) and transmission electron microdiffraction (TEMD). It has been established that the temperature of gel to gel-glass transition decreases when the Ag2O content of the gels increases. The same tendency was established for the gel to gel-glass transition in the SiO2-PtO2 system.Special attention was paid to the formation of silver and platinum metallic particles in amorphous materials. The microstructure of the gels has been observed and the sizes of the metal particles were determined to be from 3 to 25 nm.The crystallization processes in the gels heat treated at 1000–1200°C have been examined and besides the silver and platinum particles -cristobalite was formed.It has been shown that nanocomposite materials containing ultrafine silver and platinum particles in SiO2 amorphous or polycrystalline matrixes can be obtained.     

掺Nd3+碲酸盐玻璃光谱性质的研究

制备了Nd3+掺杂的碲酸盐玻璃, 测量了试样的吸收光谱、发射光谱, 计算了碲酸盐玻璃中Nd3+离子的强度参数(Ω2, Ω4, Ω6), 给出了Nd3+离子的发光特性(A, β, τrad, σ)的计算结果, 研究了其荧光特性、浓度淬灭及其机制. 研究发现组分70TeO2-20ZnO-(10-x)La2O3-xNd2O3(%,摩尔分数)碲酸盐玻璃具有高的发射截面和低声子能的特性. 当x为0.5时荧光强度和发射截面最大, 即在碲酸盐玻璃中Nd3+的最佳掺杂浓度为0.5%(1.93×1020 ions·cm-3). 碲酸盐玻璃中Nd3+离子实测荧光特性与计算结果基本一致.     

掺铒碲酸盐玻璃光谱特性研究

测试了样品(75-x)TeO2-xWO3-15ZnO-5La2O3-5Nb2O5(摩尔分数)-1%(质量分数)Er2O3(TWZ,x=0,4,8,12,15)和(75-y)TeO2-yB2O3-15ZnO-5La2O3-5Nb2O5(摩尔分数)-1%(质量分数)Er2O3(TBZ,y=0,4,8,12,15)玻璃的吸收光谱、荧光光谱、上转换光谱、能级寿命和热稳定性.应用J-O理论和McCumber理论分别计算了玻璃中Er3+离子光学跃迁强度参数Ωt(t=2,4,6)和受激发射截面.在975 nm激励下,该玻璃同时观察到了绿光(528和544 nm)和红光(660 nm)的上转换发光现象,分别对应于Er3+的.2Hu/2→4I15/2,4S3/2→4I15/2和 4F9/2→4I15/2跃迁.分析比较了玻璃中WO3和B2O3含量变化对光谱参数的影响.结果表明:随着WO3含量的增加,TWZ玻璃1.53μm波段荧光强度逐渐增大,上转换发光强度逐渐减弱,4I13/2能级寿命增加;随着B2O3含量的增加,TBZ玻璃1.53 μm波段荧光强度、上转换发光强度以及4I13/2能级寿命逐渐减弱.另外,TWZ和TBZ系列玻璃的热稳定性都有所提高.