Eu3+掺杂Y2O3-Al2O3-SiO2玻璃的制备与荧光性能研究

采用高温熔融法制备了Eu³⁺掺杂Y₂O₃-Al₂O₃-SiO₂荧光玻璃,探讨了成分对该体系玻璃形成能力的影响,并对不同Eu³⁺掺杂浓度下的荧光性能进行了研究.结果表明,熔融温度为1500℃条件下,SiO₂含量对该体系的玻璃形成能力影响明显,Y/Al摩尔比为3/5时,SiO₂含量在52%-68%(摩尔分数)范围内时可以获得玻璃.掺杂Eu³⁺的Y₂O₃-Al₂O₃-SiO₂玻璃具有荧光性能,在395nm波长激发下,在588 nm和614 nm处出现明显的发射峰.随着Eu³⁺掺杂浓度的增加,该荧光玻璃的发射波长不变,但发射强度有所变化;当Eu³⁺掺杂浓度为1.5%(摩尔分数)时,特征发射峰强度最大.     

Eu3+激活的SrO-BaO-SiO2发光材料的合成和特性研究

(Sr,Ba)SiO₃:Eu³⁺是以SrCO₃、BaCO₃、H₂SiO₃、Li₂CO₃、Eu₂(C₂O₄)₃为原料,经高温烧结而成。合成发光材料过程中,用正交试验法进行实验条件的探索。得到了发光材料的最佳组成为:(Sr_0.8Ba_0.2)_0.95Eu_0.025Li_0.025SiO₃或Si_0.95Eu_0.025Li_0.025SiO₃。最佳实验条件为:灼烧温度1150℃,灼烧时间3小时。通过X-射线粉末衍射谱、激光荧光光谱、发光光谱和激发光谱研究了发光材料的结构和发光特性。     

稀土元素与马来酸和邻菲咯啉三元固态配合物的研究

合成了13种由稀土离子(La³⁺、Pr³⁺、Nd³⁺、Sm³⁺-Yb³⁺和Y³⁺)与马来酸(C₄H₄O₄)和邻菲咯啉(Phen)形成的三元配合物。元素分析和微量水分测定确定其组成为Ln₂(C₄H₂O₄)₃(Phen)₂·4H₂O.研究了它们的紫外,红外吸收光谱,探讨了配合物的荧光性质及热稳定性。     

2.7NaF-AlF3(7wt%CaF2)-Al2O3-YM2O3体系物理化学性质的研究

本文系统研究了冰晶石熔体中添加钇族稀土碳酸盐即2.7NaF·AlF₃(7Wt%CaF₂)-Al₂O₃-YM₂O₃体系的一系列物理化学性质。 应用最优化设计原理,研究了该体系的初晶温度、表面张力、密度、粘度和电导率,分别得到了表征该体系初晶温度、粘度与Al₂O₃、YM₂O₃浓度关系的回归方程以及该体系表面张力、密度、电导率与Al₂O₃、YM₂O₃浓度和温度关系的回归方程。     

PbO2电极上S2O82-离子阳极形成过程的研究

用分解稳态极化曲线的方法,在PbO₂阳极上,H₂SO₄和H₂SO₄-(NH₄)₂SO₄溶液中得到了相应于S₂O₈^2-形成和O₂发生的动态力学数据。在高于+2.25V的电位区,这两个反应的Tafel斜率都是2.303RT/βF(β=0.52～O.55),S₂O₈^2-形成的电流效率低于29%,且几乎不随阳极电位而改变。S₂O₈^2-的形成速度与溶液中硫酸离子浓度无关,而O₂发生速度随硫酸离子浓度的增大稍有减慢。提出了在高电位区S₂O₈^2-形成及O₂发生的机理。     

硬脂酸二茂铁酯L-B膜修饰SnO2电极的阻抗研究

测定了二茂铁衍生物——硬脂酸二茂铁酯L-B膜修饰SnO₂电极在Fe(CN)₆^3-/4-溶液中的阻抗性能,用单纯形法求出了等效电路中的元件参数值,计算了电极反应速度常数K_s。从分析SnO₂电极修饰不同层的硬脂酸二茂铁酯L-B膜的界面阻抗和电极反应的动力学性能,表明与在固相中研究的硬脂酸二茂铁酯L-B膜的阻抗性能明显不同,在Fe(CN)₆^3-/4-溶液中表现了电活性分子修饰电极的界面阻抗行为,进一步证实了修饰在SnO₂电极上的硬脂酸二茂铁酯L-B膜在Fe(CN)₆^3-/4-的氧化还原电极反应过程中,起电荷传递的中介作用。     

硝酸铕18-C-6(4:3)络合物的晶体结构

标题化合物的分子式为[Eu(NO₃)₆][Eu(NO₃)₂C₁₂H₂₄O₆]₃。晶体属单斜晶系,空间群为C2/m,a=28.772(6),b=11.142(2),c=12.024(2)Å,β=112.63(2)°,Z=2。对1167个可观察反射(I≥3σ(I)),用块矩阵最小二乘法精修所有的结构参数,最后的一致性因子R=0.063。结构分析表明:晶体学上有三个不同的离子,(1)[Eu(NO₃)₆]^3-,(2)[Eu(NO₃)₂C₁₂H₂₄O₆]⁺(有序)和(3)[Eu(NO₃)₂C₁₂H₂₄O₆]⁺(无序)。前两个离子都具有C_2h对称性。第三个离子是C₁对称性,它有一个无序的冠醚环。在Fourier图上二个冠醚环叠加,它们的相互交错角为32°。     

Eu2+离子在BaF2-xREF3体系中的f→f跃迁发射

研究了Eu²⁺离子在BaF_2-xREF₃体系中的荧光光谱结构,当RE=La,Gd,Y,Lu和Sc时,降低温度或适当改变基质中阳离子间摩尔比都观察到了EU²⁺的f→f跃迁尖峰发射。     

稀土氧化物的光声光谱

本文报导了在自制的GS-1型光声光谱仪上首次测得的La₂O₃、CeO₂、Pr₆O₁₁、Nd₂O₃、Sm₂O₃、Eu₂O₃、Gd₂O₃、Tb₄O₇、Dy₂O₃、Ho₂O₃、Er₂O₃、Tm₂O₃、Yb₂O₃、Lu₂O₃等镧系元素14个稀土氧化物的光声光谱。实验结果与文献报导的漫反射谱一致。为从事稀土化合物研究和应用的人员提供了可参考的光谱数据。     

浸渍法制备的ZnO/r-Al2O3催化剂的宏观结构特点

本文系统考察了浸渍法制备的ZnO/γ-Al₂O₃催化剂的宏观结构,研究了所生成的缺锌铝酸锌(Zn_xAl₂O_3+x,02O₃的孔结构。据此,可以制取各种孔结构的Zn_xAl₂O_3+x以满足不同的要求,而共沉淀制备法难以做到这一点。     

Electrospinning Synthesis and Photoluminescence Properties of SnO2：xEu3＋ Nanofibers

NnO2：xEu3＋（x=O, 1%, 3%, 5%, molar fraction） fibers were synthesized by electrospinning technology. The size of the as-prepared fibers is relatively uniform and the average diameter is about 200 nm with a large draw ratio. The as-prepared Eu3＋ doped SnO2 nanofibers have a rutile structure and consist of crystallitc grains with an average size of about 10 nm. A slight red shift of the A1gand Bag vibration modes and an additional peak at 288 nm were observed in the Raman spectra of the nanofibers. The energies of bandgaps of the SnO2 nanofiber with Eu doping of 1% and 3% are 2.64 eV, and the energy of bandgap is 2.94 eV with Eu doping of 5%（molar fraction）. There is only orange emission（5D0→7F1 magnetic dipole transition） for Eu doped SnO2 nanofibers, and no red emission could be observed. The orange emission upon indirect excitation splits into three peaks and the peak intensity at the excitation wavelength of 275 nm is higher than that at the excitation wavelength of 488 nm.     

Pr-PVP掺杂Ti/PbO2电极制备及其在有机物降解中的应用

在Ti基体上,采用电沉积法制备了镨和聚乙烯吡咯烷酮(PVP)掺杂的Ti/SnO₂-Sb₂O₃/Pr₂O₃-PVP-PbO₂ 电极. SEM显示Ti/SnO₂-Sb₂O₃/Pr₂O₃-PVP-PbO₂ 电极表面颗粒细化,镀层结构更加致密和均匀,XRD 测试表明掺杂使可以使电极的表面颗粒变小.循环伏安 (CV)分析表明共掺杂改性后的电极电催化活性明显提高.强化寿命测试显示Ti/SnO₂-Sb₂O₃/Pr₂O₃-PVP-PbO₂ 电极稳定性更好,使用寿命更长. 将所制备的电极应用于亚甲基蓝(MB)模拟染料废水的降解测试,与常规的Ti/PbO₂ 电极相比,Ti/SnO₂-Sb₂O₃/Pr₂O₃-PVP-PbO₂ 电极对亚甲基蓝具有更好的脱色率和 COD 除去率. 降解120min 后,对30 mg·L ^-1 亚甲基蓝的去除率分别可达到99%,对COD去除率为87.9%.     

UV-Enhanced Room Temperature Ozone Sensor Based on Hierarchical SnO2-In2O3

SnO₂-In₂O₃ hierarchical microspheres were prepared by the hydrothermal and solvothermal method. The morphology, phase crystallinity of the obtained SnO₂-In₂O₃ were measured by X-ray diffraction(XRD), scan electron microscopy(SEM), respectively. A room temperature ozone sensor based on SnO₂-In₂O₃ hierarchical microspheres was fabricated and investigated. The gas sensing properties of the sensor using SnO₂-In₂O₃ strongly depended on the proportion of SnO₂ and In₂O₃. The sensitivity and response/recovery speed were greatly enhanced by UV illumination. A gas sensing mechanism related to oxygen defect was suggested.     

Li2O-CaO-Gd2O3-SiO2:Eu,Bi体系的结构和发光性能之间的关系

用X射线粉末衍射法研究了Li₂O-CaO-Gd₂O₃-SiO₂:Eu,Bi发光体系的物相组成随Gd₂O₃含量的变化,探讨了不同硅酸盐物种和结构对Eu³⁺和Bi³⁺发光特性的影响。结果表明,无Gd₂O₃组分时发光体是β-CaSiO₄多晶体,当Gd₂O₃/SiO₂比超过2.5%时,Ca₂Gd₈(SiO₄)₆O₂和LiGd₉(SiO₄)₆O₂物相逐渐增加,当其成为主要物相时,EU³⁺发光呈数倍增强,这2种含钆物相的结构既利于EU³⁺的红光发射又利于敏化剂向激活剂传输能量,所形成的固熔体是优良的发光基质材料。     

锌掺杂对SrTiO_3光催化性能的影响

制备了锌掺杂的SrTiO3光催化剂,测试了掺杂样品在400 W高压汞灯照射下,分解纯水制氢的活性。考察了锌的掺杂量及样品的焙烧温度对其光催化活性的影响,并对掺锌与未掺杂样品进行了XRD、UV-vis、XPS及SEM表征分析。结果表明,Zn掺入可显著提高SrTiO3的光催化活性,适宜的锌掺杂摩尔分数为1%左右,相应的掺杂量下,适宜的焙烧温度为950℃左右,上述条件制得掺锌SrTiO3的产氢速率较未掺杂样品提高了120%左右。表征结果显示,掺摩尔分数1%的锌未改变SrTiO3的晶体结构及结晶完整性,但样品表面发生了锌的富集,而且在一定的掺杂范围内,锌掺杂使SrTiO3催化剂的粒度有所增大。推测掺入的Zn与存在于SrTiO3表面的富钛相反应生成Zn2TiO4,使SrTiO3表面的缺陷浓度降低,光催化活性提高。     

钛基金属氧化物电极制备及其氨氮废水降解性能

采用热分解方法制备了4种电极钛基金属氧化物：Ti/SnO₂+Sb₂O₃、Ti/SnO₂+Sb₂O₃/SnO₂+IrO₂、Ti/SnO₂+Sb₂O₃/SnO₂+RuO₂和Ti/SnO₂+Sb₂O₃/SnO₂+CeO₂. X-射线衍射分析表明Ti/SnO₂+Sb₂O₃/SnO₂+CeO₂电极的CeO₂晶体结构完好,连续工作较长时间电极表面没有明显析氧. 使用该电极电解氧化氨氮模拟废水（降解2 h）,氨氮模拟废水从高浓度（500 mg·L^-1）降解为较低浓度（180 mg·L^-1）,降解效率可达64%,电解活性最佳.     

Enhanced Electrochemical Performance of Na0.67Fe0.5Mn0.5O2Cathode with SnO2 Modification

P2-type layered oxide Na_0.67Fe_0.5Mn_0.5O₂ is recognized as a very promising cathode material for sodium-ion batteries due to the merits of high capacity, high voltage, low cost, and easy preparation. However, its unsatisfactory cycle and rate performances remain huge obstacles for practical applications. Here, we report a strategy of SnO₂ modification on P2-type Na_0.67Fe_0.5Mn_0.5O₂ to improve the cycle and rate performance. Scanning electron microscope(SEM) and transmission electron microscope(TEM) images indicate that an insular thin layer SnO₂ is coated on the surface of Na_0.67Fe_0.5Mn_0.5O₂ after medication. The coating layer of SnO₂ can protect Na_0.67Fe_0.5Mn_0.5O₂ from corrosion by electrolyte and the cycle performance is well enhanced. After 100 cycles at 1 C rate(1 C=200 mA/g), the capacity of SnO₂ modified Na_0.67Fe_0.5Mn_0.5O₂ retains 83 mA·h/g(64% to the initial capacity), while the capacity for the pristine Na_0.67Fe_0.5Mn_0.5O₂ is only 38 mA·h/g(33.5% to the initial capacity). X-Ray photoelectron spectroscopy reveals that the ratio of Mn⁴⁺ increases after SnO₂ modification, leading to less oxygen vacancy and expanded lattice. As a result, the capacity of Na_0.67Fe_0.5Mn_0.5O₂ increases from 178 mA·h/g to 197 mA·h/g after SnO₂ modification. Furthermore, the rate performance of Na_0.67Fe_0.5Mn_0.5O₂ is enhanced with SnO₂ coating, due to high electronic conductivity of SnO₂ and expanded lattice after SnO₂ coating. The capacity of SnO₂ modified Na_0.67Fe_0.5Mn_0.5O₂ at 5 C increases from 21 mA·h/g(pristine Na_0.67Fe_0.5Mn_0.5O₂) to 35 mA·h/g.     

纳米晶Sb掺杂SnO2(ATO)粉体的合成与表征

以Sn粉和Sb₂O₃为原料.采用共沉淀法制备了纳米ATO粉.TG-DSC及FTIR结果表明.450℃以前前驱体已失去全部水分.并完全转化为氧化物.XRD测量结果表明.所得ATO粉具有四方金红石结构.500℃焙烧后粉体的粒径为12nm.随着焙烧温度的升高.粉体的粒径增加.TEM测定结果表明,粉体的分散性很好.团聚很少.粉体的烧结性能良好,950℃时烧结5h即达到理论密度的97.3％.用霍尔系数法测定粉体的导电行为.表明该粉体具有良好的导电性能.     

Electrochemical performance of a nano SnO2-modified LiNi1/3Co1/3Mn1/3O2 cathode material

The nano SnO₂-modified LiNi_1/3Co_1/3Mn_1/3O₂ was successfully prepared by a carrier transfer method. The pristine and modified samples were characterized with various techniques such as XRD, SEM, XPS and EDS. The results showed that the SnO₂ particles did not enter the crystal structure of LiNi1/3Co1/ 3Mn1/3O₂, many nano SnO₂ particles were uniformly covered on the surface of LiNi_1/3Co_1/3Mn_1/3O₂ and the modified thin layer could inhibit the dissolution of transition metal oxides. The electrochemical tests indicated that the existence of nano SnO₂ could improve the discharge capacity and rate capability owing to the decreased interfacial polarization. The cycling stability was remarkably improved at room temperature and 55 ℃. The XRD patterns of the fresh NCM electrode and after 50 cycles proved that the structural change of NCM was not so effective on the capacity fade.     

Oxygen-evolving SnO2-based Ceramic Anodes in Aluminium Electrolysis

This study deals with SnO₂-based ceramic anodes doped with Sb₂O₃ and CuO, aiming at contributing new data regarding their electrochemical behavior in cryolite melts. The performances of the anodes were evaluated by anodic polarization, cyclic voltammetry, and current efficiency and corrosion measurements. The investigation proves that the anodic process of SnO₂-based inert anodes occurs at a low overvoltage and the oxygen discharge takes place in one step with an exchange of two electrons. The current efficiency and corrosion were proved to be dependent on the electrolysis parameters and composition of electrolysis bath. For a long term electrolysis, the dissolution of the anode in the cryolite-alumina melt produced small aluminium contamination(ca. 0.2%, mass fraction).