AlCl3(ZnCl2,MgCl2)对Sm2O3的氯化效果及电化学行为

研究了AlCl₃(ZnCl₂、MgCl₂)对Sm₂O₃的氯化效果以及Sm₂O₃在LiCl-KCl-AlCl₃(ZnCl₂、MgCl₂)熔盐体系中的电化学行为。在LiCl-KCl-Sm₂O₃熔盐中加入AlCl₃(ZnCl₂、MgCl₂)后,ICP测量结果表明,AlCl₃体系中Sm(Ⅲ)离子的浓度最高,并且在923 K时达到最大值;固相反应表明,AlCl₃氯化Sm₂O₃生成SmCl₃,而Sm₂O₃和ZnCl₂(MgCl₂)反应生成SmOCl。电化学行为表明,AlCl₃体系中观察到了两种Al-Sm的合金峰,而ZnCl₂体系中只观察到Zn-Sm金属间化合物的形成峰,MgCl₂体系中没有形成合金。在-6.25 A·cm^-2下,W电极上恒电流电解2 h获得了Al-Li-Sm合金,经XRD分析,合金为Al₂Sm相。     

在LiCl-KCl-AlCl3熔盐中直接电化学还原Sm2O3及Al-Sm合金的形成

在803 K LiCl-KCl熔盐中,研究了通过添加助剂AlCl3直接电化学还原Sm2O3和Al-Sm合金的形成。以SmCl3为原料作为参照,采用循环伏安和方波伏安方法,研究了Sm2O3在LiCl-KCl-AlCl3熔盐体系中的电化学行为。通过对比发现在两个体系中,峰的数量和位置基本一致,这说明在LiCl-KCl熔盐中,加入AlCl3之后,可以将Sm2O3有效氯化。计时电位结果表明,当阴极电流比-139.8 mA.cm-2更负时,Al和Sm共同还原。为了提取Sm,采用恒电流从LiCl-KCl-AlCl3-Sm2O3熔盐中电解得到Al-Sm合金样品,并进行XRD表征,结果表明可以通过调节AlCl3和Sm2O3的浓度得到不同相的Al-Sm合金。     

稀土掺杂Lu3Al5O12荧光粉的发光特性及能量传递

采用高温固相法制备了Ce、Sm共掺Lu₃Al₅O₁₂荧光粉。通过X射线衍射分析、荧光光谱分析研究了样品的结构、发光特性,并通过理论计算研究了能量传递效率、能量传递的临界距离以及能量传递方式。X射线衍射分析表明所制备的荧光粉具有单一的石榴石结构;荧光光谱分析表明,在464 nm蓝光激发下,Sm³⁺的引入可增加Lu₃Al₅O₁₂：Ce,Sm发射光谱中红光成分,并且随着Sm³⁺浓度的增加,Ce³⁺发光强度逐渐减弱。计算出Ce³⁺、Sm³⁺之间的能量传递效率高达77.42%,确定了Ce³⁺、Sm³⁺之间的能量传递机制为偶极-偶极相互作用。     

(ZrO2)0.86(Sm2O3)0.14纳米粉体的水热法合成及其烧结体的电性能

以湿化学法制得Zr(OH)₄和Sm(OH)₃的共沉淀为前驱体, 在碱性介质中用水热法合成了(ZrO₂)_0.86(Sm₂O₃)_0.14及(ZrO₂)_0.88(Sm₂O₃)_0.12纳米粉体. 将纳米粉体在较低温度(1450 ℃)下烧结制得了致密的固体电解质陶瓷样品, 比通常高温固相反应法采用的烧结温度(＞1600 ℃)降低了150 ℃以上. XRD测定结果表明, (ZrO₂)_0.86(Sm₂O₃)_0.14纳米粉体及其烧结体均为立方相, 但(ZrO₂)_0.88(Sm₂O₃)_0.12纳米粉体为立方相, 它的烧结体为立方相和单斜相的混合相. 用交流阻抗谱法、氧浓差电池法及氧泵(氧的电化学透过)法研究了(ZrO₂)_0.86(Sm₂O₃)_0.14陶瓷样品在600～1000 ℃下的离子导电特性. 结果表明, 该陶瓷样品在600～1000 ℃下氧离子迁移数为1, 氧离子电导率的最大值为3.2×10^－2 S•cm^－1, 是一个优良的氧离子导体; 它的氧泵性能明显地优于YSZ.     

质子导体BaCe0.4Zr0.4M0.2O3-δ (M=In，Y，Gd，Sm)化学稳定性及电性能

采用高温固相法制备了不同阳离子掺杂的BaCe_0.4Zr_0.4M_0.2O_3-δ (M=In,Y,Gd,Sm)系列质子导体。运用X射线衍射仪、扫描电子显微镜分别对四类质子导体的物相结构、微观形貌进行了表征,应用IM6e型电化学工作站测定了其不同温度下的阻抗谱,并对样品在CO₂和沸水中的稳定性进行了研究。结果表明：除Sm³⁺掺杂的质子导体有少量的杂质相Sm₂O₃外,其他3种均为单相立方晶钙钛矿结构;对CO₂和沸水皆表现良好的化学稳定性;Y³⁺掺杂的质子导体具有高的电导率,800 ℃约为2.07×10^-2 S·cm^-1,空气气氛电导活化能为72.34 kJ·mol^-1。     

Sm3+掺杂CaO-SiO2-B2O3发光玻璃的制备、表征及性质

用高温固相法合制备了以CaO-SiO₂-B₂O₃为基质，Sm³⁺为激活离子的发光玻璃。对Sm³⁺的淬灭浓度、基质中的硼硅比例、其他稀土离子的敏化作用以及基质组成等因素对玻璃发光特性的影响进行了探讨，并用红外和X-衍射分析对样品的结构进行了表征。结果表明：当Sm^3＋掺杂的物质的量分数为1.2%,激发波长λ ＝ 404 nm时,玻璃体60CaO-20SiO₂-20B₂O₃∶1.2Sm^3＋的发光强度为4 838 A.U.( λ ＝ 606 nm );这种发光玻璃具有将紫外及近紫外光转换为橙红色光的特点。少量的Eu^3＋的掺入，对玻璃体的发光起敏化作用；玻璃体中的组分CaO可被ZnO替代。     

层状Co3O4的制备及其电化学电容行为

以P123为模板水热合成制备了Co₂(OH)₂CO₃前驱体，200 ℃热处理后得到了具有层状结构的Co₃O₄。循环伏安、恒流放电等电化学测试表明，200 ℃所得Co₃O₄电极在6 mol·L^-1 KOH溶液中和-0.1～0.5 V(vs Ag/AgCl)电位范围内，具有较好的循环稳定性能，单电极比电容达到505 F·g^-1。     

MgCl2在LiCl-KCl熔盐中的电化学特性

研究了温度范围在723-908 K的LiCl-KCl 熔盐体系中MgCl₂的电化学行为和热力学性质. 循环伏安和方波伏安法研究表明镁离子的电化学还原过程为包含了两个电子转移的一步反应. 利用Berzins 和Delahay 方程计算了不同温度下的镁离子的扩散系数, 并通过Arrhenius 公式计算了镁离子在LiCl-KCl 熔盐体系中的扩散活化能. 采用开路计时电位法得到了不同温度下的Mg(II)/Mg(0)体系的平衡电位, 并结合电动势法计算了在LiCl-KCl 熔盐体系中Mg(II)/Mg(0)体系的标准形式电位. 根据不同温度下的标准形式电位, 计算得到了MgCl₂在LiCl-KCl 熔盐体系中的熵变和焓变以及不同温度下的活度系数.     

层状LiCo1/3Ni1/3Mn1/3O2正极材料的合成及电化学性能研究

采用液相法在800 ℃空气中烧结20 h合成出层状LiCo_1/3Ni_1/3Mn_1/3O₂正极材料。通过XRD、IR、SEM、XPS和电化学性能测试考察了产物的组成、结构、形貌及电化学性能。结果表明，所合成的LiCo_1/3Ni_1/3Mn_1/3O₂为六方单相，层状结构发育完善；产物呈球形且粒度小，分布窄，平均粒径为0.3 μm。以1 mA·cm^-2的电流密度，在2.7～4.3 V区间进行充放电测试，前4周的充放电比容量分别为168/160 mAh·g^-1、169/162 mAh·g^-1、165/160 mAh·g^-1、163/158 mAh·g^-1，循环性能优良。循环伏安实验表明，该材料在3.9 V附近出现了一对对称性好的氧化还原峰。     

AlCl3(ZnCl2,MgCl2)对Sm2O3的氯化效果及电化学行为

研究了AlCl_3(ZnCl_2、MgCl_2)对Sm_2O_3的氯化效果以及Sm_2O_3在Li Cl-KCl-AlCl_3(ZnCl_2、MgCl_2)熔盐体系中的电化学行为。在Li Cl-KCl-Sm_2O_3熔盐中加入AlCl_3(ZnCl_2、MgCl_2)后,ICP测量结果表明,AlCl_3体系中Sm(Ⅲ)离子的浓度最高,并且在923 K时达到最大值;固相反应表明,AlCl_3氯化Sm_2O_3生成SmCl_3,而Sm_2O_3和ZnCl_2(MgCl_2)反应生成Sm OCl。电化学行为表明,AlCl_3体系中观察到了两种Al-Sm的合金峰,而ZnCl_2体系中只观察到Zn-Sm金属间化合物的形成峰,MgCl_2体系中没有形成合金。在-6.25 A·cm~(-2)下,W电极上恒电流电解2 h获得了Al-Li-Sm合金,经XRD分析,合金为Al_2Sm相。     

Selective extraction of gadolinium from Sm2O3 and Gd2O3 mixtures in a single step assisted by MgCl2 in LiCl–KCl melts

The chloration of MgCl₂ was studied in the LiCl–KCl–MgCl₂–Gd₂O₃–Sm₂O₃ melts. Gd(III) and Sm(III) ions were observed by cyclic voltammetry and square wave voltammetry assisted by MgCl₂ in melts. X-ray diffraction (XRD) patterns of melts indicated Gd₂O₃ and Sm₂O₃ were chlorinated by MgCl₂ and formed GdCl₃ and SmCl₃. XRD patterns of non-dissolved residues, which were left after the melts were washed with water to remove the soluble salt, showed that the new compounds (i.e., GdOCl, SmOCl, MgO, Gd(OH)₃, and Sm(OH)₃) were produced. Potentiostatic electrolysis experiments were performed to extract Gd from Gd₂O₃ and Sm₂O₃ mixtures assisted by MgCl₂. Separation between Gd₂O₃ and Sm₂O₃ was also achieved in a single step with the formation of Mg–Li–Gd alloys. XRD patterns of alloys indicated that Mg₃Gd phase was formed. Scanning electron microscope images with energy dispersive X-ray spectroscopy showed Gd elements were mainly distributed in the grain boundary.     

Synthesis, structural characterization and properties of a 3D infinitely extended structural rare earth coordination compound of K3{[Sm(H2O)7]2Na[α-SiW11O39Sm(H2O)4]2} · 14 H2O· 14 H2O

A 3D infinitely extended structural rare earth coordination compound with a formula of K₃{[Sm(H₂O)₇]₂Na[α-SiW₁₁O₃₉Sm(H₂O)₄]₂}·14H₂O has been synthesized by reaction of Sm₂O₃, HClO₄, NaOH with α-K₈SiW₁₁O39·nH₂O, and characterized by IR, UV spectra, ICP, TG-DTA, cyclic voltammetry, variable-temperature magnetic susceptibility and X-ray single-crystal diffraction. X-ray single-crystal diffraction indicates that the title compound crystallizes in a triclinic lattice, Pī space group, with a = 1.2462(3) nm, b = 1.2652(3) nm, c = 1.8420(4) nm, α = 87.45(3)°, β = 79.91(3)°, γ= 82.57(3)°, Z = 1, R₁ = 0.0778, wR₂ = 0.1610. Structural analysis reveals that Sm³⁺(1) coordination cation has incorporated into the vacant site of [α-SiW11O₃₉]⁸⁻ entity, forming the [α- SiW₁₁O₃₉Sm(H₂O)₄]⁵⁻ subunit. The two adjacent [α-SiW₁₁O₃9Sm(H₂O)4]⁵⁻ subunits are combined with each other through two Sm(1)-O-W bridges accompanying the formation of dimmer structural unit [α-SiW₁₁O₃₉Sm(H₂O)₄]₂ ¹⁰⁻ of the title compound. The neighboring dimmer structural units [α-SiW₁₁O₃₉Sm(H₂O)₄]₂ ¹⁰⁻ are linked to form the 1D chainlike structure by means of two Sm³⁺(2) and a Na⁺(1) coordination cations. The K⁺(1) cations connect the 1D packing chains constructing the 2D netlike structure, and adjacent netlike layers are also grafted by K⁺(2) cations to build the novel 3D infinitely extended structure. The result of TG-DTA curves manifests that the decomposition temperature of the title polyanionic framework is 554°C. The cyclic voltammetry measurements show that the title polyanion has the two-step redox processes in aqueous solution with pH = 3.1. Variable temperature magnetic susceptibility indicates the title compound obeys the Cruie-Weiss Law in the higher temperature range from 110 to 300 K, while in the lower temperature range from 2 to 110 K the comparatively strong antiferromagnetism interactions can be observed.     

稀土掺杂Lu3Al5O12荧光粉的发光特性及能量传递

采用高温固相法制备了Ce、Sm共掺Lu_3Al_5O_(12)荧光粉。通过X射线衍射分析、荧光光谱分析研究了样品的结构、发光特性,并通过理论计算研究了能量传递效率、能量传递的临界距离以及能量传递方式。X射线衍射分析表明所制备的荧光粉具有单一的石榴石结构;荧光光谱分析表明,在464 nm蓝光激发下,Sm~(3+)的引入可增加Lu_3Al_5O_(12)∶Ce,Sm发射光谱中红光成分,并且随着Sm~(3+)浓度的增加,Ce~(3+)发光强度逐渐减弱。计算出Ce~(3+)、Sm~(3+)之间的能量传递效率高达77.42%,确定了Ce~(3+)、Sm~(3+)之间的能量传递机制为偶极-偶极相互作用。     

Sm2O3Ga2O3 and Gd2O3Ga2O3 phase diagrams

Four definite compounds exist in the Sm₂O₃Ga₂O₃ binary phase diagram, namely: Sm₃GaO₆, Sm₄Ga₂O₉, SmGaO₃, and Sm₃Ga₅O₁₂. The $\text{3}\text{1}$ compound is orthorhombic (space group Pnna - Z.4) with the cell parameters: a = 11.40₀Å, b = 5.51₅Å, c = 9.07Å and belongs to the oxysel family. Sm₃GaO₆ and SmGaO₃ melt incongruently at 1715 and 1565°C; Sm₄Ga₂O₉ and Sm₃Ga₅O₁₂ have a congruent melting point at 1710 and 1655°C. With regard to the Gd₂O₃Ga₂O₃ system three definite compounds have been identified: Gd₃GaO₆, Gd₄Ga₂O₉, and Gd₃Ga₅O₁₂. Only the garnet melts congruently at 1740°C with the following composition: Gd_3.12Ga_4.88O₁₂. Gd₃GaO₆, and Gd₄Ga₂O₉ melt incongruently at 1760 and 1700°C. GdGaO₃ is only obtained by melt overheating which may yield an equilibrium or a metastable phase diagram.     

Photoluminescence of samarium-doped TiO2 nanotubes

Samarium (Sm)-modified TiO₂ nanotubes (TNTs) were synthesized by low-temperature soft chemical processing. X-ray powder diffraction analyses of the synthesized Sm-doped and non-doped TNTs show a broad peak near 2θ=10°, which is typical of TNTs. The binding energy of Sm ³d_5/2 for 10 mol% Sm-doped TNT (1088.3 eV) was chemically shifted from that of Sm₂O₃ (1087.5 eV), showing that Sm existed in the TiO₂ lattice. Sm-doped TNTs clearly exhibited red fluorescence, corresponding to the doped Sm³⁺ ion in the TNT lattice. The Sm-doped TNT excitation spectrum exhibited a broad curve, which was similar to the UV–vis optical absorption spectrum. Thus, it was considered that the photoluminescence emission of Sm³⁺-doped TNT with UV-light irradiation was caused by the energy transfer from the TNT matrix via the band-to-band excitation of TiO₂ to the Sm³⁺ ion.     

Electrochemical Behaviour and Chemical Species of Sm(II) in AlCl3-NaCl with Different Lewis Acidity

AlCl₃-NaCl was utilized as an electrolyte in this work due to its low melting point and Lewis acidity, in which samarium exists in two oxidation states, Sm(III) and Sm(II), resulting in unique electrochemical behaviours. Sm metal dissolves in AlCl₃-NaCl melt to form SmCl₂, which is verified by electrochemical and spectroscopic techniques. As the Lewis acidity of the melt increases, the diffusion coefficient of Sm(II) gradually increases, and the activation energy of diffusion decreases. Moreover, an additional co-reduction peak of Sm³⁺ and AlCl₄⁻ is observed to be more positive than that of Al(0)/Al(III) in Lewis basic melt, which may be tightly correlated with the variation of Sm(II) coordination in AlCl₃-NaCl melt and ligand variation from Cl⁻ to AlCl₄⁻ and Al₂Cl₇⁻ as the Lewis acidity of the AlCl₃-NaCl melt increases, according to the in situ electronic absorption spectra of Sm in this melt.     

Effects of Sm Co-doping on Luminescent Properties of Sr4Al14O25:M (M=Mn4+, Cr3+) Phosphors

The Sr₄Al₁₄O₂₅:M and doped Sr₄Al₁₄O₂₅:M+Sm³⁺ (M=Mn⁴⁺, Cr³⁺) phosphors were syn-thesized by a solid-state reaction method and their luminescent properties were investi-gated. The results showed that the co-doping of Sm ions did not change the positions of excitation band and emission band but signi cantly improved the luminescent properties of Sr₄Al₁₄O₂₅:Cr³⁺ phosphors; whereas, the emission intensity of Sr₄Al₁₄O₂₅:Mn⁴⁺ was re-dueced remarkably when Sm ions were co-doped. In addtion, a radiative-form energy transfer from Sm³⁺ to Cr³⁺ was observed for the first time in the Cr, Sm co-doped Sr₄Al₁₄O₂₅ phos-phors. The results indicated that Sm ions could signi cantly improve the emission intensity of Sr₄Al₁₄O₂₅:Cr³⁺, making the Sm³⁺co-doped Sr₄Al₁₄O₂₅:Cr³⁺ phosphor a promising can-didate for the applications in display and solid state lightening.