纳米晶镍—钼合金电沉积层的结构与性能

通过控电流沉积制备出纳米晶镍钼合金沉积层,沉积层的ＸＲＤ、ＸＰＳ结果表明,纳米晶镍钼合金沉积层存在较大的晶格畸变,其微晶尺寸为１７ｎｍ,纳米合金各元素的结合能发生了不同程度的位移．在３０％的ＫＯＨ溶液中纳米晶镍钼合金电极对析氢反应表现出较高的电催化活性．电化学交流阻抗谱表明,析氢过程按ＶｏｌｍｅｒＨｅｙｒｏｖｓｋｙ机理进行．     

Manipulation of Structure on Silicon Surfaces via Chemical Adsorption

Via chemical adsorption, various films were assembled onto silicon surfaces. The structures and properties of the monolayer‐ or bilayer‐modified silicon surfaces, such as Si‐C₁₀H₂₀ CH₂OC(O)CF₃, Si‐C₁₀H₂₀CH₂OH, and Si‐C₁₀H₂₀‐CH₂‐NH‐C₁₈H₃₇, were investigated by various techniques. x‐ray photoelectron spectroscopy (XPS) gave clear proofs of the formation of octadecylamine layer and other kinds of layers on silicon surfaces. The contact angle measurements showed that the wettability of silicon surfaces was dominated by the terminal functional groups of the attached layers. Atomic force microscopy (AFM) observations showed that interesting patterns have formed on the monolayer‐ or bilayer‐modified silicon surfaces. Electrochemical impedance spectra (EIS) measurements showed that the Si‐C₁₀H₂₀CH₂‐NH‐C₁₈H₃₇ has a better ability to prevent charge transfer as compared with that of Si‐C₁₀H₂₀CH₂OH, which may find applications in the area of surface passivations.     

REUSY-Ex的吸附性能及二次孔结构研究

应用高真空重量法(分别以苯和正庚烷为吸附质)和低温N2吸附法对REUSY-Ex的吸附性能和二次孔结构进行了研究.结果表明,在水热处理过程中可产生二次孔结构,且二次孔的形成与水热处理的脱铝深度相关.稀HCl浸取REUSY不仅能浸取出位于其二次孔中的非骨架铝(EFAL)碎片,而且还能浸取出位于微孔中的EFAL。29Si MAS NMR的结果显示,稀HCl浸取后,骨架Si(OAl)的谱宽变窄,裂分效果提高,表明其化学环境单一或均匀.     

Synthesis,Structure and Electrochemical Properties of Acetamide- and Caprolactam-Containing Silicon Catecholates

Hexacoordinated heteroligand silicon catecholates, although being prospective as easily soluble compounds with high hydrolytic stability and diverse redox properties, have been insufficiently studied. The transesterification of 1-(trimethoxysilylmethyl)-2-oxohexahydroaze or N-methyl-N-(trimethoxysilylmethyl)acetamide by two equivalents of catechol derivatives in the presence of dicyclohexylamine afforded a series of target compounds in good yield. The complexes were characterized using elemental analysis, FTIR, ¹H, ¹³C and ²⁹Si NMR spectra, X-ray crystallography and cyclic voltammetry. X-ray diffraction confirmed that the silicon atom possesses the octahedral geometry of the SiCO₅ polyhedron that remains unchanged in solution as it follows from ²⁹Si NMR data. The compounds demonstrated up to three oxidation waves; and the reduction profile strongly depended on the nature of the substituents on a catecholate anion.     

螯合树脂研究（XXVI）氮杂冠醚型树脂的合成及其吸附性能

用环氧氯丙烷低聚物分别与二（三）乙醇胺的钠盐进行反应，合成了两种氮杂冠醚型交联树脂．研究了树脂对贵金属和一些个过渡金属的吸附性能．树脂对Ａｕ（Ⅲ）具有较高的吸附容量和吸附率。在Ｃｕ（Ⅲ）－Ｐｄ（Ⅱ）－Ｐｔ（Ⅳ）混合液中优先吸附Ａｕ（Ⅲ）；在Ｃｕ（Ⅱ）—Ｚｎ（Ⅱ）和Ｃｕ（Ⅱ）—Ｃｏ（Ⅱ）—Ｎｉ（Ⅱ）的混合液中只吸附Ｃｕ（Ⅱ）而不吸附其他金属离子．     

Structure and Adsorption Properties to TVOC of Orange Peel Modified with KOH

Food waste orange peel was employed as a raw material to prepare biomass adsorbent to solve the indoor Total Volatile Organic Compounds(TVOC). The preparation process of orange peel treated with KOH was optimized by the quadratic regression orthogonal rotation, and the regression model and optimal processing conditions were obtained. The structure of the adsorbent was characterized by BET, SEM, TEM, EDS, XRD and FTIR analysis. The adsorption properties and desorption regeneration were discussed. The results showed the maximal removal rate Ymax was 9.4824% when KOH concentration was 0.3 mol/L, the soaking time of KOH was 26 h and that of HCl was 2.89 h. The best single factor condition was the adsorbent with 40 mesh size and 6.0 g. The adsorption of modified orange peel on TVOC conformed to the Freundlich models, which was more inclined to multi-layer active site adsorption. The adsorption law followed the quasi-second-order kinetic model(R~2 = 0.955), indicating the adsorption was a physico-chemical mixture but controlled by physical adsorption and it was a spontaneous endothermic process. The modified orange peel exposed more sites and had stronger chemical groups, which were beneficial to adsorption. The adsorbent has a significantly better TVOC removal rate than other materials at 1% level, that is, modified orange peel diatomite activated carbon bamboo charcoal macroporous resin. In addition, it had good recycling and regeneration capacity.     

纳米晶钛酸钡的介电性能

采用硬脂酸凝胶法制备了纳米晶BaTiO3,用差热热重分析、红外光谱分析、X射线衍射分析等手段对产物的形成过程、晶型、粒径进行了分析.通过对材料介电性能的研究发现,纳米材料的静态介电常数远大于常规材料的介电常数,随着粒径的减小,纳米材料的介电常数先增大而后有所降低.随着环境湿度的升高,纳米晶材料的介电常数逐渐增大,在高湿度条件下,其介电常数与湿度成线性关系.     

Crystal Growth Kinetics of Nanocrystalline ZnS under Surface Adsorption

The crystal growth mechanism,kinetics,and microstructure development play a fundamental role in tailoring the materials with controllable size and morphology. In this study,by introducing the strong surface adsorption of the concentrated NaOH,two-stage crystal growth kinetics of ZnS nanoparticles was observed. In the first stage,the primary particles grow into a size over a hundred times of the original volume and the growth is controlled by the crystal-lographically specific oriented attachment. The first stage data were fitted by the "multistep OA kinetic model" built based on the molecular collision and reaction. In the second stage,following the dispersal of nanoparticles,an abrupt transition from asymptotic to parabola growth kinetics occurs,which can be fitted by a standard Ostwald ripening volume diffusion model. The presence of surface adsorption causes the two-stage growth kinetics and permits an almost exclusive OA-based growth to dominate in the first stage.     

Adsorption of Deoxyribonucleic Acid on Nanocrystalline Titanium and Cerium Dioxide Surfaces

Colloid Journal - Adsorption of deoxyribonucleic acid on the surfaces of nanosized titanium and cerium dioxides from aqueous solutions has been studied as depending on pH and adsorbate...     

同晶置换改性FAU分子筛结构及吸附性能的密度泛函理论研究

采用密度泛函理论(DFT)方法,考察了八面沸石(FAU)型分子筛β笼孔道结构内含氧化合物(甲醇、二甲醚、丙醛)的吸附,并进一步计算研究了Zn,Ca同晶置换改性的作用机理.研究结果表明,β笼孔道结构内,Al原子为甲醇、二甲醚和丙醛的吸附活性位,Si原子无吸附活性.Zn,Ca掺杂的β笼结构内,正2价的Zn和Ca掺杂替换正3价的Al,导致邻近的Si原子位置形成缺电子空穴,增强了甲醇、二甲醚和丙醛的吸附,而杂原子Zn和Ca本身并没有吸附活性.     

层状和MSU结构的介孔纳米二氧化锆

在不添加任何结构稳定剂的条件下, 首次用固态反应结构导向法成功地合成了具有层状结构和MSU结构的介孔纳米二氧化锆. 研究发现, 通过有效地控制晶化条件, 二氧化锆的晶相、比表面和孔结构可以方便地得以调变. 晶相的转变由粒度大小控制, 并且构成无机骨架的相态不同, 合成样品的热稳定性存在差异. 结果显示, 介孔纳米二氧化锆的形成仍遵循超分子液晶模板机制, 且由碱锆摩尔比的大小控制介观相的转化, 低碱锆摩尔比条件下形成层状相, 而高碱锆摩尔比条件下为维持整个体系的低能稳定状态, 在电荷作用下形成反棒状胶束结构.     

胆红素在纳米TiO2膜上的吸附行为研究

采用石英晶体微天平现场技术,研究了胆红素在纳米TiO2表面的吸附动力学行为,并考察了溶液pH、硅烷亲脂性试剂及金属离子修饰的纳米TiO2对胆红素吸附的影响。结果表明,胆红素在纳米TiO2表面的吸附平衡常数K为2·0×106L/mol;由于亲水性纳米TiO2表面的羟基和胆红素分子中的羧基发生作用,胆红素吸附量随溶液pH增大而增大;但经过硅烷试剂亲脂性修饰后,吸附量随pH增大而下降;经过金属离子修饰后,改变了TiO2表面电荷导致吸附量增加,且吸附量随金属离子电荷增加而增加,当金属离子所带电荷相同时,吸附量基本相同。     

Effect of Binder on the Structure and Properties of Silicon Powder-supported TiO2 Photocatalysis Material

Recoverable TiO2 photocatalysis material supported by silicon powder was prepared with sol-gel method, afterwards the silica gol and sodium silicate were used as molding binder respectively to investigate their effects （including binder type and binder addition quantity） on the crystal structure and catalysis properties of photocatalyst. In this work, the catalysis activity was defined as the degradation rate of methyl orange solution upon ultraviolet lamp irradiation, and the specific areas were determined with nitrogen desorption method. TiO2 crystal form was measured with X-ray powder diffraction and their micro-morphology was observed with SEM. Experimental results indicate that these two binders do not affect the crystal form transformation of TiO2, but silica gol can increase the specific surface area of TiO2 photocatalyst obviously and the addition of sodium silicate can decrease it. In all, silica gol is a better candidate than sodium silicate for higher catalysis property. In conclusion, 6% silica gol is the optimal addition concentration. Under this condition, the ratio of anatase to rutile TiO2 is 64：36, the specific area is 29.67 m^2/g, and as expected, the degradation rate of methyl orange could be as high as 90% after irradiation for 5 days.     

牛血清白蛋白在超薄纳米二氧化钛膜表面的印迹与吸附

基于溶胶凝胶分子印迹方法,以溶胶二氧化钛TiO2为基质印迹了牛血清白蛋白分子。用1%的NaOH溶液可有效地除去纳米TiO2印迹膜中的模板分子。采用石英晶体微天平现场技术,研究了牛血清白蛋白在超薄纳米TiO2膜表面的吸附行为。研究表明,牛血清白蛋白在印迹膜和非印迹膜上的吸附量都随溶液浓度增加而增大,印迹膜具有吸附的特异性和可再生性,其吸附量是非印迹膜的3~5倍;在非印迹膜上的吸附符合Langmuir吸附模型,而在印迹膜上的吸附符合allosteric吸附模型;牛血清白蛋白在非印迹膜上的吸附量先随pH升高而增大,当pH为5左右时达到最大值,随后吸附量又随pH的增大而减小;而在印迹膜上其吸附量仅随pH增大而增大。     

氧化钒/多孔硅/硅结构的微观形貌、纳米力学及温敏特性

采用电化学腐蚀法在硅基片表面形成多孔硅, 利用直流对靶反应磁控溅射方法在不同电流密度条件下制备的多孔硅样品表面上溅射沉积了VOx薄膜, 获得了氧化钒/多孔硅/硅(VOx/PS/Si)结构. 采用场发射扫描电镜(FESEM)观测多孔硅及VOx/PS/Si结构的微观形貌, 采用纳米压痕仪器测量VOx/PS/Si结构的纳米力学特性, 通过电阻-功率曲线分析研究其温度敏感特性. 实验结果表明, 在40和80 mA·cm-2电流密度下制备多孔硅的平均孔径分别为18和24 nm, 用显微拉曼光谱法(MRS)测量其热导率分别为3.282和1.278 kW·K-1; VOx/PS/Si结构的电阻随功率变化的平均速率分别为60×10⁹和100×10⁹ Ω·W-1, VOx/PS/Si结构的显微硬度分别为1.917和0.928 GPa. 实验结果表明, 多孔硅的微观形貌对VOx/PS/Si结构的纳米力学及温敏特性有很大的影响, 大孔隙率多孔硅基底上制备的VOx/PS/Si 结构比小孔隙率多孔硅基底上制备的具有更高的温度灵敏度, 但其机械稳定性也随之下降.     

Fe原子吸附对单层WS_2结构和性质的影响

本文采用基于密度泛函理论(DFT)的第一性原理方法研究了Fe原子吸附对单层WS_2结构和性质的影响。研究结果表明:Fe原子吸附在W原子的顶位最稳定,相应的原子吸附能为1.84 eV。Fe与衬底间的相互作用削弱了紧邻W―S键,使其键长增大0.011 nm。由于衬底原子的影响,Fe原子d轨道的电子重新分布,形成了2μB左右的局域原子磁矩。在低覆盖度下(0.125和0.25 ML),磁性作用以超交换作用为主,铁磁序不稳定。而在高覆盖度下(0.5和1.0 ML),Fe原子间距减小,磁性作用以RKKY作用为主,铁磁序稳定。电子结构的计算结果显示,在高覆盖度下,Fe/WS_2结构在费米能级处的电子自旋极化率等于100%。自旋向上与向下通道分别为间接带隙的半导体和金属。在1.0 ML覆盖度下,自旋向上的禁带宽度约为0.94 eV。这说明Fe原子吸附可以将直接带隙的WS_2半导体转变成半金属,形成一种潜在的自旋电子器件材料。     

Photoluminescence Properties of Surface-Modified Nanocrystalline ZnS : Mn

DBS surface-modified nanocrystalline ZnS : Mn was prepared by a precipitation method. Photoluminescence spectra and decay curves were measured and compared to those of unmodified samples. For both kinds of samples, luminescence decay curves of 600 nm emission consist of two components with nanosecond (ns) and millisecond (ms) lifetimes. The nanosecond component is attributed to zinc vacancies luminescence, with peak located at 440 nm. While the millisecond component is attributed to Mn(2+) luminescence and its decay time changes with Mn(2+) concentration and surface modification. The surface-modified sample has a longer lifetime compared to unmodified samples. The photoaging of surface-modified samples is slow. Particle size effects on photoaging were also examined. For nanocrystalline ZnS : Mn photoaging is more noticeable than that of bulk material. After UV irradiation, photoluminescence intensity of the modified sample is several times larger than that of the unmodified sample, because the surface-active reagent decreases surface defects and depresses radiationless transitions. XPS yields direct evidence of the surface-modification effect on the surface structure. Copyright 2000 Academic Press.     

Synthesis,Crystal Structure and Gas Adsorption Properties of Metal-organic Supercontainer Based 2,6-Naphthalenedicarboxylate Linker

A new sulfonylcalixarene-based coordination container 1 was designed and synthesized from the self-assembly reaction of p-tert-butylsulfonylcalix[4]arene (TBSC),Co(II) ion,and 2,6-naphthalenedicarboxylic acid (NDC).It crystallizes in tetragonal system,space group I4/m with a=b=30.9119(19)A,c=43.565(3)A,V=41628(6)A³,D_c=0.731 g/cm³,M_r=9162.36,C₃₈₄H₃₄₈Co₂₄O₁₂₆S₂₄,Z=2,F(000)=9384,μ=0.566 mm^–1,the final GOOF=1.027,R=0.0987 and w R=0.2474 for 7240 observed reflections with I>2σ(I).Structural analyses indicate that 1 adopts an edge-directed octahedral geometry and consists of six TBSC-supported Co₄ tetranuclear units locating on the vertices and twelve NDC bridging ligands occupying the edges.The new compound exhibits outstanding performance for the C₂ hydrocarbons separation over CH₄.