金属载体催化剂的涂层研究

在高温氧化处理不同时间的金属载体箔片上涂覆MgAl2O4/Al2O3过渡涂层,利用TG-DSC,XRD,SEM,BET和超声振动等分析测试技术,对载体和涂层的微观结构与表面特性进行研究.结果表明,在950 ℃下高温氧化5 h,箔片表面生成板状Al2O3晶须,有利于增强涂层与箔片的附着力.在载体表面涂覆一层MgAl2O4/Al2O3过渡涂层,有助于提高活性组分与金属载体的结合力,可以获得高结合强度的涂层结构,促使活性元素高度分散.     

金属载体表面氧化及预载处理对氧化铝涂层结合性能的影响

对FeCrAl基体进行高温氧化后,再浸渍MgAl2O4/Al2O3过渡涂层,利用XRD、 SEM和超声波振动等方法研究了样品的表观性质和涂层的结合性能.结果表明,一定时间的氧化处理可以在金属基体上形成粗糙的表层,增加涂层粘结的表面积.共沉淀法制备的尖晶石前驱体凝胶反应活性大,可作为粘结剂掺入浆料中,制备均匀的MgAl2O4/Al2O3过渡涂层.在金属载体表面氧化及预载处理后,可采用传统浸渍工艺负载γ-Al2O3分散涂层,并保证涂层的结合力.     

机动车尾气净化催化剂金属载体涂层的研究

采用Fe-Cr-Al-Y金属载体为研究对象,用氧化-磷化和溶胶-凝胶技术在金属载体表面形成活性γ-Al2O3涂层,实验确定了合适的磷化温度和磷化时间、溶胶中γ-Al2O3浓度和升温机制,结果证明预先在载体表面涂覆一层氧化-磷化膜,有助于提高活性组分与金属载体的结合力,可以获得高结合强度且活性组分均匀分布的涂层.     

高频脉冲沉积微晶Ni-20Cr-Y2O3ODS合金涂层

采用高频电脉冲沉积技术在1Cr18Ni9Ti不锈钢表面上沉积了含弥散Y2O3氧化物的纳米级MGH754 ODS合金微晶涂层, 涂层与基体具有冶金结合. 在1 000℃静态空气中100 h恒温氧化实验结果表明:微晶化和添加弥散氧化物促进了涂层中的铬选择氧化形成Cr2O3, 并提高了表面氧化膜的黏附性, 改善了不锈钢抗高温氧化性能.     

频脉冲沉积微晶Ni-20Cr-Y_2O_3ODS合金涂层

采用高频电脉冲沉积技术在1Cr18Ni9Ti不锈钢表面上沉积了含弥散Y2O3氧化物的纳米级MGH754 ODS合金微晶涂层, 涂层与基体具有冶金结合. 在1 000℃静态空气中100 h恒温氧化实验结果表明：微晶化和添加弥散氧化物促进了涂层中的铬选择氧化形成Cr2O3, 并提高了表面氧化膜的黏附性, 改善了不锈钢抗高温氧化性能.     

稀土-过渡族金属非晶态磁光薄膜表面氧化的物理过程研究

本文报道用表面效应(光电子能谱,极克尔效应)和体效应(磁化强度,矩曲线)研究稀土-过渡族金属(RE-TM)非晶态磁光薄膜表面氧化的物理过程。稀土选择性氧化,在薄膜表面富集,过渡族金属在氧化层内贫乏。表面氧化层内的Fe_2O_3对平面磁化有贡献,且在转矩曲线上180°处出现异常峰,其峰值大小和表面氧化层深度有关。铁比钴容易和氧结合,RE-Co磁光薄膜有奸的抗湿抗氧性能。     

电脉冲沉积铝化物及铝化物-Y_2O_3涂层

采用电脉冲沉积技术在 2 0碳钢表面上获得了冶金结合的晶粒尺寸约为几十到几百纳米的铝化物和铝化物 弥散Y2 O3复合微晶涂层。60 0℃空气中氧化 10 0h的结果表明 ,电脉冲沉积获得的两种涂层均可显著地降低 2 0碳钢的氧化速率并提高氧化层的抗剥落性能。用AFM ,SEM ,EDS和XRD对铝化物涂层及氧化层进行了分析 ,并讨论了两种涂层提高抗氧化性能的作用机制     

电脉冲沉积铝化物及铝化物—Y2O3涂层

采用电脉冲沉积技术在20碳钢表面上获得了冶金结合的晶粒尺寸约为几十到几百纳米的铝化物和铝化物＋弥散Y2O3复合微晶涂层,600度空气中氧化100h的结果表明,电脉冲沉积获得的两种涂层均可显著地降低20碳钢的氧化速率并提高氧化层的抗剥落性能,用AFM,SEM,EDS和XRD对铝化物涂层及据氧化层进行了分析,并讨论了两种涂层提高抗氧化性能的作用机制。     

ZnO包覆LiNi_(1/3)Co_(1/3)Mn_(1/3)O_2的表面结构和电化学性能

在LiNi1/3Co1/3Mn1/3O2正极材料表面包覆ZnO,通过X射线衍射(XRD)和光电子能谱(XPS)分析包覆层对正极材料表面状态的改变,并考察了改性后材料的放电容量、首次不可逆容量等电化学性能变化.结果表明:ZnO主要存在于材料表面并影响着材料表面组成和电化学性质,材料表面镍和锰的含量随着包覆量的增加而增大;400oC热处理可使过渡金属与锌在材料表面形成复合氧化物,过渡金属的结合能增大;包覆2%(by mass,下同)的ZnO可有效抑制55 oC下充放电时3.6 V附近的不可逆反应,提高了材料的首次库仑效率;包覆2%ZnO的电池材料在55oC/0.5C的放电比容量和循环寿命最佳.     

基于MOF@TiN-Ag/银溶胶复合基底的茶碱表面增强拉曼检测

以制备的MOF@TiN-Ag/银溶胶复合基底为表面增强拉曼光谱(SERS)活性基底，对茶碱进行SERS检测，探讨了基于该复合基底的表面增强拉曼技术在药物检测方面的应用。首先，利用电化学阳极氧化结合氨气还原氮化法制备了氮化钛纳米管阵列，随后通过电化学沉积法制备TiN-Ag复合基底，并在其表面原位生长金属有机框架(MOF)包覆层得到MOF@TiN-Ag复合基底，将茶碱与银溶胶混合后滴加在该复合基底上进行表面增强拉曼光谱检测。结果表明，MOF@TiN-Ag/银溶胶复合基底中存在面心立方晶型TiN、金属单质Ag和MOF钴基3种物相；扫描电镜结果显示，TiN纳米管排列整齐，Ag纳米结构呈树枝状均匀分散在其表面；作为隔绝层的MOF粒子形状规整，覆盖在TiN-Ag表面；银溶胶纳米粒子呈圆球状分布在MOF@TiN-Ag复合基底表面。由于银纳米粒子与TiN-Ag复合基底可发生协同增强作用，加之MOF的富集特性，使得该复合基底具有优异的SERS性能，其对茶碱溶液的SERS检出限为1×10^-5 mol/L，检测性能良好。所制备的MOF@TiNAg/银溶胶复合基底拓宽了SERS在药物检测...     

Er^3＋／Yb^3＋共掺杂AlF3基氟化物玻璃材料的频率上转换

Er^3 /Yb^3 共掺杂的AlF3基氟化物玻璃材料ABCY的制备及其上转换荧光性质。样品的组分为40AlF3-20BaF2-20CaF2-(20-2x-2y)YF3-xEr2O3-yYb2O3。在950nm连续LD激发下,观察到该材料很强的绿色上转换发光,研究了该体系的上转换机理,认为Yb^3 和Er^3 之间的APTE效应是最主要的上转换途径。解释了红、绿色上转换荧光强度比值增大的现象,指出了可能的交叉弛豫过程。用公式y=a(x-x0)^n对上转换荧光强度与LD工作电流的关系进行拟合,得到的结果与理论值很好地一致。     

Influence of the Er3+ Content on the Luminescence Properties and on the Structure of Er2O3-SiO2 Xerogels

Er₂O₃-SiO₂ xerogels doped with different Er/Si concentrations were annealed at 950°C for 120 h. The Er³⁺ doping level varied from 0 to 40000 Er/Si ppm. The effect of Er₂O₃ content on the sintering behavior of silica gels and on the luminescence properties was studied by Vis-NIR absorption, Raman and luminescence spectroscopies.     

Effect of Zn2+ Ions on Upconversion Emission of Er3+ in Zn/Er:LiNbO3 Crystal

The effect of Zn2+ ions codoped on the upconversion emission of Er3+ ions in Er:LiNbO3 crystal under different excitation wavelength was reported.The upconversion emission spectra of Zn/Er:LiNbO3 follo...     

Color tuning by co-doping of Er doped TiO2 phosphors within a fixed Er concentration

In this paper, we report the color tuning of Er doped TiO₂ upconversion phosphors within a fixed Er concentration using 976 nm semiconductor laser diode excitation. By codoping with Mo, Yb or Li ions in the Er doped TiO₂, the green and red upconversion emissions from the ²H_11/2/⁴S_3/2 → ⁴I_15/2 and ⁴F_9/2 → ⁴I_15/2 transitions of Er ions were enhanced selectively and the color output of Er doped TiO₂ could be tuned by different intensity ratios of green to red emissions. The two-photon absorption processes were responsible for the green and red upconversion emissions of Er–Mo, Er–Yb and Er–Li codoped TiO₂ phosphors, and the corresponding enhanced mechanisms were discussed. It is expected that these color tuned phosphors within a fixed Er concentration have great potential for applications in biology, displays and other optical technology.     

Er对Al-Ni-Er-Zr非晶合金动力学特性的影响

采用单辊旋淬法首次制备了Al85Ni10ErxZr5-x(x=3,4,5)非晶合金,利用X射线衍射(XRD)证明Al85Ni10ErxZr5-x(x=4,5)结构为完全非晶态,Al85Ni10Er3Zr2合金为部分非晶。应用差示热分析法(DTA)测定该合金的热学参量,分析了其晶化过程。利用Kissinger法计算了非晶合金的晶化激活能。研究了Er的增加对于Al-Ni-Er-Zr系合金非晶形成能力和热稳定性的影响。结果表明:Er的增加提高了该合金体系非晶形成能力和热稳定性。     

Temperature-dependent six-photon upconversion fluorescence of Er

Yb³⁺/Er³⁺ codoped β-NaYF₄ microcrystals were synthesized through a facile EDTA-assisted hydrothermal method. Under 980 nm excitation, 244, 256, and 276 nm upconversion (UC) emissions were observed in NaYF₄:Yb³⁺/Er³⁺ microcrystals, which were assigned to the ²I_11/2 → ⁴I_15/2, ⁴D_7/2 → ⁴I_15/2, and ⁴G_9/2 → ⁴I_15/2 transitions of Er³⁺ ions, respectively. Successive energy transfers (ETs) from Yb³⁺ to Er³⁺ played crucial roles in populating the high-energy states of Er³⁺ ions. Power dependence analysis exhibited that 244 and 256 nm UC emissions came from six-photon processes. Temperature-dependent UC emissions of ⁴D_7/2 → ⁴I_15/2 and ²I_11/2 → ⁴I_15/2 transitions of Er³⁺ were discussed and the nonradiative relaxation (NR) process of ²I_11/2 → ⁴D_7/2 was confirmed.     

Sulfate und Hydrogensulfate des Erbiums: Er(HSO4)3-I,Er(HSO4)3-II,Er(SO4)(HSO4) und Er2(SO4)3

Sulfates and Hydrogensulfates of Erbium: Er(HSO₄)₃-I, Er(HSO₄)₃-II, Er(SO₄)(HSO₄), and Er₂(SO₄)₃ Rod shaped light pink crystals of Er(HSO₄)₃-I (orthorhombic, Pbca, a = 1195.0(1) pm, b = 949.30(7) pm, c = 1644.3(1) pm) grow from a solution of Er₂(SO₄)₃ in conc. H₂SO₄ at 250 °C. From slightly diluted solutions (85%) which contain Na₂SO₄, brick shaped light pink crystals of Er(HSO₄)₃-II (monoclinic, P2₁/n, a = 520.00(5) pm, b = 1357.8(1) pm, c = 1233.4(1) pm, β = 92.13(1)°) were obtained at 250 °C and crystals of the same colour of Er(SO₄)(HSO₄) (monoclinic, P2₁/n, a = 545.62(6) pm, b = 1075.6(1) pm, c = 1053.1(1) pm, β = 104.58(1)°) at 60 °C. In both hydrogensulfates, Er³⁺ is surrounded by eight oxygen atoms. In Er(HSO₄)₃-I layers of HSO₄^– groups are connected only via hydrogen bridges, while Er(HSO₄)₃-II consists of a threedimensional polyhedra network. In the crystal structure of Er(SO₄)(HSO₄) Er³⁺ is sevenfold coordinated by oxygen atoms, which belong to four SO₄^2–- and three HSO₄^–-tetrahedra, respectively. The anhydrous sulfate, Er₂(SO₄)₃, cannot be prepared from H₂SO₄ solutions but crystallizes from a NaCl-melt. The coordination number of Er³⁺ in Er₂(SO₄)₃ (orthorhombic, Pbcn, a = 1270.9(1) pm, b = 913.01(7) pm, c = 921.67(7) pm) is six. The octahedral coordinationpolyhedra are connected via all vertices to the SO₄^2–-tetrahedra.     

纳米CeO2∶Er荧光粉的光声光谱和荧光光谱研究

采用燃烧法合成了CeO2∶Er纳米荧光粉, 研究了不同粒径大小的CeO2∶Er的晶型和晶貌.TEM结果表明无定形CeO2∶Er包围着纳米晶CeO2∶Er, 可起到表面修饰的作用.光声光谱在保持纳米材料表面状态不改变的前提下, 分析了不同粒径的CeO2∶Er的光谱性质, 解释了随纳米粒径减小CeO2光谱峰吸收峰有蓝移而Er3+没有明显谱峰位移的原因.在荧光光谱中, 发现小粒径的CeO2∶Er有较大的红绿发射比, 并对该现象进行了解释.     

Cluster Organic Framework Based on Er3 and Cu5 Cluster Units

A novel cluster organic framework, Er₃Cu₅I₄L₁₀(H₂O) (1, L = 4-pyridin-3-yl-benzonate), has been hydrothermally made and structurally characterized by single crystal X-ray diffraction. Structure analysis shows [Er₃(COO)₆]³⁺ (Er₃) clusters are linked by carboxylate groups generating one dimensional wave-like chain, which further extended by Cu₅I₄ ⁺ (Cu₅) clusters into three dimensional heterometallic cluster organic framework. From the perspective of topology, such framework defines a new (7,9)-connected net, considering Er₃ and Cu₅ cores as the nodes. Furthermore, the elemental analysis, powder X-ray diffraction, infrared spectra and thermogravimetric analysis are also studied.