氯化钠在球形纳米氧化铈形成过程中的作用

以水合碳酸铈为原料, 以氯化钠作为助磨剂和阻聚剂, 采用机械活化法制备了球形纳米氧化铈, 用XRD法研究了水合碳酸铈与氯化钠质量比、球磨时间、煅烧温度对CeO2粉体晶粒度的影响, 用TEM对最终产物粒子进行形貌观察. 结果表明: 在碳酸铈的球磨过程及其随后的煅烧过程中, 氯化钠的存在起到了很好的助磨和阻聚作用, 所得CeO2为类球形粒子, 分散性较好, 晶粒度约为30～50 nm.     

Preparation of solutions of amidomagnesium chlorides in poly(ethylene oxide) and their characterization by conductivity measurements

Polymer electrolyte systems were prepared for the first time by dissolution of amidomagnesium chlorides in poly(ethylene oxide), (PEO). For the preparation, solutions of (hexamethyldisilylamido)magnesium chloride, (dimethylpyrrolyl)magnesium chloride, (diisopropylamido)magnesium chloride, piperidinomagnesium chloride and morpholinomagnesium chloride were chosen. The composition of these polymer electrolyte systems corresponds to the general formula R₂NMgCl·P(EO)_n·THF. Most work has been done with the system (hexamethyldisilylamido)magnesium chloride in PEO, (Me₃Si)₂NMgCl·P(EO)_n·THF, with n= 3, 4, 5, or 7. The electrolytes have a soft rubber-like consistency. At 30 °C, electrical conductivities of 10⁻⁶–10⁻⁵ S/cm were found. The conductivities were measured in the temperature range 20–60 °C. Within this temperature range a linear dependence of the logarithms of the conductivity on the inverse temperature was found and activation energies for the conducting process of 30–60 kJ/mol were calculated. Using those polymer electrolytes with a high content of the amidomagnesium compound, a reversible magnesium deposition takes place by cathodic reduction at potentials below −1.9 V vs. a Ag/AgCl reference electrode. These polymer electrolytes were found to be stable against oxidation up to about −0.3 V vs. Ag/AgCl. Electronic Publication     

异烟酸在银溶胶上的表面增强喇曼散射及影响因素

本文研究了异烟酸吸附在银溶胶表面的表面增强喇曼散射(SERS)光谱以及卤素离子、溶液pH值及溶液浓度对异烟酸SERS光谱的影响。文章提出了离子在银溶胶表面的吸附方式,即主要以—COO~-端吸附于银溶胶表面。最后,对所述实验现象作了定性讨论。     

介孔Co3O4-CeO2复合氧化物的制备及在CO选择性氧化中的应用

以硝酸钴和硝酸铈为前驱物，SBA-15为硬模板，利用双溶剂法制备了Co3O4-CeO2介孔复合氧化物，通过X-射线衍射、N2吸脱附测试、程序升温还原和透射电子显微镜等技术对活性组分及载体进行了表征，并且与浸渍法和共沉淀法所制备的催化剂进行了对比分析。结果表明，相比于浸渍法和共沉淀法，采用双溶剂法制备的介孔Co3O4-CeO2复合氧化物具有均匀的介孔结构、较小的颗粒尺寸、较大的比表面积和较高的活性组分分散度。此外，CO氧化脱除评价显示与常规的共沉淀法和浸渍法所制备的催化剂相比该介孔复合氧化物具有较高的反应活性和选择性，其高活性主要归因于较高的比表面积和活性组分的高分散度。     

Mixed micellization of an anionic gemini surfactant (GA) with conventional polyethoxylated nonionic surfactants in brine solution at pH 5 and 298 K

The micellization behavior of an anionic gemini surfactant, GA with nonionic surfactants C₁₂E₈ and C₁₂E₅ in presence of 0.1 M NaCl at 298 K temperature, has been studied tensiometrically in pure and mixed states, and the related physicochemical parameters (cmc, γ _cmc, pC ₂₀, Γ _max, and A _min) have been evaluated. Tensiometric profile (γ vs log [surfactant]), for conventional surfactants, generally consists of a single point of intersection; a gradually decreasing line (normally linear, or with slight curvature) ultimately saturates in γ at a particular [surfactant], corresponding to complete monolayer saturation. The gemini, in this report, led to two unequivocal breaks in the tensiometric isotherm. An attempt to the interpretation of the two breaks from molecular point of view is provided, depending solely on the chemical structure of the surfactant. The gemini, even in mixed state with the conventional nonionic surfactants C₁₂E₅ and C₁₂E₈, manifested the dual breaks; of course, the dominance of the feature decreases with increasing mole fraction of the nonionics in the mixture. Theories of Clint, Rosen, Rubingh, Motomura, Georgiev, Maeda, and Nagarajan have been used to determine the interaction between surfactants at the interface and micellar state of aggregation, the composition of the aggregates, the theoretical cmc in pure and mixed states, and the structural parameters according to Tanford and Israelachvili. Several thermodynamic parameters have also been predicted from those theories.     

水热法合成Ce0.67Zr0.33O0.2固溶体研究

采用两种不同前驱体通过水热法合成了Ce0.67Zr0.33O0.2固溶体,并通过XRD,BET,TPR等手段考察了样品的相结构,比表面及还原特性.结果表明,在180℃,12 h的水热条件下,以共沉淀产物为前驱体所制得的Ce0.67Zr0.33O0.2固溶体比表面积较高,但存在一定程度的相分离;以凝胶产物为前驱体制得的Ce0.67Zr0.33O0.2固溶体结构更完整,具有良好的还原特性及热稳定性.     

Surface Modification of Fine Particles with a SnO<Subscript>2</Subscript> Film by Using a Polyhedral-Barrel Sputtering System

Fine particles were modified with a thin film of SnO₂ by using a barrel sputtering system that is a dry process. The conditions for the preparation of SnO₂ were studied by reactive sputtering onto a glass plate substrate. The optimal conditions for the preparation of tetragonal SnO₂ were identified as 60% partial oxygen pressure and 1.0 Pa total gas pressure with the substrate at room temperature. Under the optimized conditions, the surfaces of Al flake particles were modified with a thin film of SnO₂. XRD and SEM/EDS analysis of the prepared samples showed that the Al particle surfaces were uniformly modified by a thin film of SnO₂ in all cases. The film thicknesses were 80, 130, and 180 nm at RF outputs of 195, 350, and 490 W. These measured thicknesses coincided with the values estimated from the interference colors of the samples.     

含氮宾或卡宾的金属羰基簇合物的结构化学研究——Ⅰ.H_2Fe_3(N-C_6H_5)(CO)_9和Fe_3(N-C_6H_5)(μ_3-CO)(CO)_9的合成和结构

含氮宾的两个三核羰基铁簇合物是由[Et_3NH][HFe_3(CO)_(11)]与C_6H_5NCO在苯中反应获得。应用四园衍射仪测定了H_2Fe_3(N-C_6H_5)(CO)_9(Ⅰ)和Fe_3(N-C_6H_5)(μ_3-CO)(CO)_9(Ⅱ)的晶体结构。晶体数据为:C_(15)H_7NO_9Fe_3(Ⅰ),空间群P2_1/a,a=18.343(2),b=9.072(1),c=11.451(1)(?),β=102.03(1)°,V=1863.7(?)~3,Z=4,D_c=2.143g/cm~3;C_(16)H_5NO_(10)Fe_3(Ⅱ),空间群P2_1/c,a=8.634(1),b=13.026(1),c=17.642(2)(?),β=97.68(1)°,V=1966.3(?)~3,Z=4,D_c=1.820g/cm结构系用直接法解出,最后R_(Ⅰ)因子为0.033,R_(Ⅱ)因子为0.027。测定结果表明,(Ⅰ)和(Ⅱ)分子均具有C_s对称性,且三个Fe原子共面,呈近似等边三角形结构。(Ⅰ)中面桥N原子以不对称方式与三个Fe原子成键;(Ⅱ)中面桥羰基以不对称方式与三个Fe原子键连。Fe-N和Fe-C键长分别在1.896-1.938(?)和2.006-2.110(?)之间。     

不同晶型和粒径的二氧化钛微粉对金属离子的吸附行为

考察了在流动注射的微柱分离富集体系中不同晶型和粒径的TiO2微粉对Cu2 , Cr3 , Mn2 , Ni2 , La3 , Eu3 , Ga3 , Mo(Ⅵ)和W(Ⅵ) 等金属离子的吸附pH条件及动态吸附容量, 并进行了比较; 初步探讨了TiO2微粉的吸附机制. 结果表明, 当TiO2的粒径大小相近时, 晶型对吸附容量的影响不可忽略; 当晶型相同时, 粒径的大小则起着重要的作用.