纳米银胶的光化学制备及其特性研究

采用紫外光化学法制备了黄色银胶,并研究了硝酸银和柠檬酸三钠的浓度对制备的银胶吸收光谱的影响,发现随着硝酸银浓度的增加银胶的吸收峰先兰移然后红移;当柠檬酸三钠的浓度增加时,硝酸银吸收峰的位置几乎不变,而吸收峰强度增大.最后通过透射电镜成像研究其尺寸,发现其尺寸分布在5~20 nm之间.     

金属基体上铝溶胶涂层的制备

 以拟薄水铝石为原料,采用HNO3胶溶法制备了铝溶胶,研究了制备条件对胶体性质的影响. 结果表明,拟薄水铝石的含量和HNO3的加入量是影响胶体粒度大小、粒径分布以及胶体稳定性的重要因素. 当拟薄水铝石的含量为4.5%~5.5%、酸加入量为［H+］/［AlOOH］=0.08~0.1(摩尔比)时,可以得到颗粒度小(平均粒径≤19.3 nm),粒径分布范围窄(4.1~53 nm)和稳定性好的胶体溶液. 以该胶体为过渡涂层涂覆在金属基体上. 在能形成稳定胶体的前提下,酸度相同时,胶体的浓度越大,粘度越大,涂覆到基体上的量就越多; 但是过渡涂层的牢固度似乎与胶体的浓度关系不大. 金属基体的前处理条件也是一个重要的因素,它不仅影响过渡层的涂覆量,也影响涂层的牢固度.     

CONDUCTIVITY BEHAVIOR OF IONIC AI(OH)3-POLYACRYLAMIDE HYBRIDS IN AQUEOUS SOLUTIONS

The conductivity behavior of Al(OH)3-acrylamide hybrid polyacrylamide (hybrid PAAm) in distilled water was studied. A discontinuity phenomenon of the conductivity (k) versus concentration (c) curve of the hybrid PAAm in a certain concentration regime is found. This phenomenon is dependent on the molecular weight of the hybrid PAAm and on the particle size and content of the Al(OH)3 colloid in the hybrid PAAm. This phenomenon was accounted for assuming ionization of the hybrid PAAm.     

正电性磁性氧化铁胶粒负载钯催化的Suzuki偶联反应

发展了一种超顺磁性Fe3O4纳米粒子负载Pd0的简易方法. 利用Fe3O4溶胶带正电荷的特性, 将负离子 通过静电作用吸附在Fe3O4胶体粒子表面( /Fe3O4), 以抗坏血酸(Vc)进一步还原即得到载有金属Pd团簇的Fe3O4胶体粒子(Pd0/Fe3O4). 该磁性载体负载的Pd催化剂对Suzuki反应表现出良好的催化活性, 且在反应后, 可方便地通过永久磁铁将催化剂从反应体系中分离出来, 进行循环使用. 试验表明, 该催化剂在循环使用五次后反应活性无明显下降. 进一步试验发现, 这种磁性纳米粒子负载的金属钯对一系列卤代芳烃的Suzuki偶联反应均表现出较优的催化活性.     

Surfactant-free fabrication of Cu2O nanosheets from Cu colloids and their tunable optical properties

Novel sheetlike Cu₂O two-dimensional (2D) nanoarchitectures were successfully synthesized via a copper nanoparticle-mediated process for the first time. Uniform and nearly monodisperse Cu nanocolloids were firstly synthesized by disproportionating reaction of Cu⁺ at the surfactant-free ambient conditions, and Cu₂O nanosheets were subsequently synthesized by choosing ethanol solvent agent to limit the oxidized processes of Cu nanocolloids. The synthesized products were systematically studied by X-ray powder diffraction, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV-vis absorption spectra. It was demonstrated that the solvent agent of ethanol played key roles in the formation of the as-synthesized nanosheets. By choosing the different solvent agents to limit the oxidized processes, Cu₂O nanospheres and nanocubes can be selectively synthesized accordingly.     

Novel Nanomaterials Based on Inorganic Molybdenum Octahedral Clusters

In this contribution, we present a review of our recent works about the design of phosphor nanoparticles and materials based on [Mo₆X₁₄]²⁻ cluster units (X = Cl, Br, I) as well as the functionalization of monocrystalline Si(111) surfaces by Mo₆ clusters. Our purpose was to use the specific properties of cluster units found in inorganic solids for the design of new nanomaterials with potential applications in nanotechnologies (e.g. phosphor dyes for bio labelling, light emitting diodes, redox active molecular junctions…) using soft chemistry techniques. Phosphor Cs₂Mo₆X₁₄@SiO₂ nanoparticles emitting in 550–900 nm upon photo-excitation were synthesised using a ‘water in oil’ microemulsion technique. They exhibit a regular shape (~45 nm) and are based on [Mo₆X₁₄]²⁻ cluster units and Cs⁺ counter cations embedded in a silica matrix. ((n–C₄H₉)₄N)₂Mo₆Br₁₄@ZnO colloids and nanopowders are based on the association of ZnO crystalline nano-particles with Mo₆ cluster units adsorbed on their surface. They exhibit a large emission window in the visible region that can be tuned by modulation of the excitation wave length in order to selectively obtain the emission of either clusters units or ZnO nanocrystals or of both entities. Functionalized surfaces were obtained by the attachment of cluster units on a Si(111) surface through pyridine end capped organic chains using a multi-step procedure. Modified surfaces were characterized by X-ray photoemission spectroscopy (XPS), atomic force microscopy (AFM), IR and electrochemical analysis. The surface coverage can be modulated by the controlled introduction of inert organic chains among pyridine end-capped ones before the cluster anchoring step.     

稠油胶质沥青分散解堵剂性能评价与现场应用

为了解决稠油开采过程中由于胶质沥青沉淀析出堵塞储层,造成蒸汽吞吐开采中注汽压力高以及井筒举升和管线输送困难等问题,提出了稠油胶质沥青分散解堵技术,并对稠油胶质沥青分散解堵剂进行性能评价.室内评价与现场应用结果表明,该分散解堵剂能极强地溶解、分散稠油中的胶质沥青及杂环芳烃,并能抗凝固防沉降,在温度低于10℃以下仍具有较好的溶解分散能力.注汽过程中添加该分散解堵剂能有效防止胶质、沥青质沉积,疏通液体流动通道,大幅度降低注汽压力;此外还能有效降低稠油黏度,提高原油在低温下的流动性,改善稠油在井筒的举升能力及地面的集输效果.     

胶体离子超级电容器的比容量评价

胶体离子超级电容器作为一种新型的超级电容器,其同时具有能量密度和功率密度高的独特优势。 目前已经发展了包括多种过渡金属阳离子和稀土阳离子,例如Mn²⁺、Fe²⁺、Co²⁺、Ni²⁺、Cu²⁺、Sn²⁺、Sn⁴⁺、La³⁺、Ce³⁺、Er³⁺和Yb³⁺的胶体离子超级电容器体系。 在电化学反应中,识别出电活性物质的存在形式对研究电极反应机理和提高比容量具有重要价值。 本文主要通过对电活性物质比容量的探讨,理解这种新型胶体离子超级电容器的电化学储能机理。 评述了胶体离子超级电容器的比容量核算方式,提出了以阳离子为标准核算比容量的原因,并与传统超级电容器的核算方式进行了比较,表明胶体离子超级电容器在提高能量密度方面具有潜在优势,有望突破现有电化学储能设备的技术瓶颈,实现下一代高能量储能器件的开发。     

硒化钨花状纳米晶的可控合成及电催化产氢性能研究

采用胶体化学法,以氧化钨(W18O49)为钨源制备出花状硒化钨纳米晶.采用透射电子显微镜(TEM)、高分辨透射电镜(HRTEM)和X射线衍射(XRD)手段对硒化钨纳米晶进行表征.本文对硒化钨花状纳米晶体的可控合成进行了初步探索,同时对烧结后的硒化钨纳米晶进行了电催化产氢测试.结果表明,硒化钨花状纳米晶具有良好的电催化性能.     

有机溶胶法制备Pt/C催化剂的影响因素研究

有机溶胶法制备高分散的Pt/C催化剂是目前制备活性组分高度分散的燃料电池催化剂的一种新方法,本文考察了在有机溶胶法制备催化剂的过程中,碳载体的预处理以及制备条件对催化剂性能的影响,实验结果表明：在适当的温度下对碳载体进行热处理可以显著改善活性组分的分散和提高催化剂的性能;在惰性气氛中还原制得的催化剂的性能明显优于在空气气氛中还原制得的催化剂,较低温度有利于获得活性组分颗粒度较小的催化剂,起始PH值大于10时制得的催化剂的活性明显高于PH小于10时制得的催化剂。采用优化条件制备的Pt/C催化剂对甲醇氧化的电化学性能和抗中毒性能显著优于E-TEK Pt/C催化剂。