新型金属盐萃取剂的开发以及与卤化钯络合性质的初步研究

研究了一类新型的金属盐萃取剂,通过紫外可见光谱分析、核磁滴定分析以及测定配合物的元素含量等方法研究了这种新型萃取剂与卤化钯的络合特性。     

金属氧化物纳米颗粒溶胶-凝胶合成概述

文章介绍了金属氧化物纳米颗粒的水溶胶-凝胶合成与非水溶胶-凝胶合成的一般工艺过程和影响合成工艺的主要因素,总结了常见合成反应的类型与简单反应机理.并对作水合成中的表面活性剂控制与溶剂控制两种方法的优缺点进行了比较.     

金属纳米粒子修饰的碳纳米管研究进展

多壁和单壁碳纳米管（CNT）是被广泛研究的纳米材料之一,可以用作良好的金属或其它纳米粒子的载体。金属纳米粒子-碳纳米管复合材料在催化、传感、贮氢、及各种光学电学方面有广泛的应用前景,文章就近期各种碳纳米管负载的金属纳米材料（主要集中在贵金属）的合成做一小结。     

Novel Two-Step Synthesis of Controlled Size and Shape Platinum Nanoparticles Encapsulated in Mesoporous Silica

Uniform shape and size platinum nanoparticles encapsulated in mesoporous silica (SBA-15) were prepared in the same solution by a novel two-step method. Platinum nanoparticles were prepared in aqueous solution of K₂PtCl₄, the reduction was carried out by bubbling hydrogen, the capping material was tri-block poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) copolymer. The mesoporous silica was synthesized using the same copolymer as template from tetraethyl orthosilicate by hydrolysis in acidic conditions. The Pt-nanoparticles-in-mesoporous-silica system was characterized by a combination of low-angle powder X-ray diffraction, transmission electron microscopy and N₂ porosimetry. The platinum nanoparticles are encapsulated in the mesopores and retained their size and morphology. It appears that this hybrid material should be a superior three-dimensional high-surface-area catalyst for selective platinum-catalyzed reactions.     

Antimicrobial Properties of Palladium and Platinum Nanoparticles: A New Tool for Combating Food-Borne Pathogens

Although some metallic nanoparticles (NPs) are commonly used in the food processing plants as nanomaterials for food packaging, or as coatings on the food handling equipment, little is known about antimicrobial properties of palladium (PdNPs) and platinum (PtNPs) nanoparticles and their potential use in the food industry. In this study, common food-borne pathogens Salmonella enterica Infantis, Escherichia coli, Listeria monocytogenes and Staphylococcus aureus were tested. Both NPs reduced viable cells with the log₁₀ CFU reduction of 0.3–2.4 (PdNPs) and 0.8–2.0 (PtNPs), average inhibitory rates of 55.2–99% for PdNPs and of 83.8–99% for PtNPs. However, both NPs seemed to be less effective for biofilm formation and its reduction. The most effective concentrations were evaluated to be 22.25–44.5 mg/L for PdNPs and 50.5–101 mg/L for PtNPs. Furthermore, the interactions of tested NPs with bacterial cell were visualized by transmission electron microscopy (TEM). TEM visualization confirmed that NPs entered bacteria and caused direct damage of the cell walls, which resulted in bacterial disruption. The in vitro cytotoxicity of individual NPs was determined in primary human renal tubular epithelial cells (HRTECs), human keratinocytes (HaCat), human dermal fibroblasts (HDFs), human epithelial kidney cells (HEK 293), and primary human coronary artery endothelial cells (HCAECs). Due to their antimicrobial properties on bacterial cells and no acute cytotoxicity, both types of NPs could potentially fight food-borne pathogens.     

Efficient Hydrogenation of Nitrogen Heterocycles Catalyzed by Carbon‐Metal Covalent Bonds‐Stabilized Palladium Nanoparticles: Synergistic Effects of Particle Size and Water

We reveal here the first hydrogenation of nitrogen heterocycles catalyzed by carbon–metal covalent bonds‐stabilized palladium nanoparticles in water under mild conditions. Using a one‐phase reduction method, smaller metal–carbon covalent bond‐stabilized Pd nanoparticles were prepared with a size distribution of 2.5±0.5 nm, which showed extraordinary synergistic effects with water in the catalytic hydrogenation of nitrogen heterocycles. Water was supposed to accelerate substrate absorption and synergistic activation of molecular hydrogen on the Pd nanoparticles surface. The nanosized Pd catalyst could be easily recovered and reused for 5 runs.

     

钯、铂贵金属催化剂的工业应用

介绍了TH、THC、TO系列钯、铂贵金属催化剂的主要特性,通过工业生产应用实例,分别论述了TH-2、TH-3催化剂在尿素生产中脱氢,THC-1催化剂在食品级CO2气体中脱烃,TH-4催化剂在高浓度CO气体中脱氧方面的生产运行数据、催化剂操作参数和生产应用效果。     

Biphasic Hydrogenation of Olefins by Functionalized Ionic Liquid‐Stabilized Palladium Nanoparticles

Palladium nanoparticles in the size range of 5–6 nm were prepared conveniently by reducing palladium(II) with atmospheric pressure hydrogen and stabilized by 2,2′‐dipyridylamine‐functionalized imidazolium cations according to our approach. The efficient catalytic conversion of cyclohexene into cyclohexane by the functionalized ionic liquid‐stabilized palladium nanoparticles has been performed under very mild hydrogen pressure (0.1 MPa) and at 35 °C. It was found that the concentration of palladium and the reaction temperature considerably affected the size and degree of aggregation of Pd nanoparticles in ionic liquid, which further changed the performance of the catalyst activity. The synthesized nanocatalysts can be recycled at least five times without any loss of the activity. Finally, the scope of substrates was also investigated. The excellent catalytic activity of the present system can be attributed to good stabilization and high dispersion of palladium nanoparticles.     

一步法制备新型荧光聚合物纳米粒子

采用一步细乳液聚合法将荧光单体4-甲胺基-9-(2-烯丙基)-1,8-萘二甲酰亚胺(MANI)共价键结合进聚合物纳米粒子中.光谱特性研究证明了MANI已经成功结合进人纳米粒子中.更重要的是,因为MANI通过共价键的方式结合进聚合物纳米粒子中,可以有效避免产生染料泄漏现象.并且可以通过控制纳米粒子中MANI的含量,来获得...     

Metal Sulfide Semiconductor Nanomaterials and Polymer Microgels for Biomedical Applications

The development of nanomaterials with therapeutic and/or diagnostic properties has been an active area of research in biomedical sciences over the past decade. Nanomaterials have been identified as significant medical tools with potential therapeutic and diagnostic capabilities that are practically impossible to accomplish using larger molecules or bulk materials. Fabrication of nanomaterials is the most effective platform to engineer therapeutic agents and delivery systems for the treatment of cancer. This is mostly due to the high selectivity of nanomaterials for cancerous cells, which is attributable to the porous morphology of tumour cells which allows nanomaterials to accumulate more in tumour cells more than in normal cells. Nanomaterials can be used as potential drug delivery systems since they exist in similar scale as proteins. The unique properties of nanomaterials have drawn a lot of interest from researchers in search of new chemotherapeutic treatment for cancer. Metal sulfide nanomaterials have emerged as the most used frameworks in the past decade, but they tend to aggregate because of their high surface energy which triggers the thermodynamically favoured interaction. Stabilizing agents such as polymer and microgels have been utilized to inhibit the particles from any aggregations. In this review, we explore the development of metal sulfide polymer/microgel nanocomposites as therapeutic agents against cancerous cells.     

离子液体稳定的金属纳米粒子制备及其催化作用研究进展

离子液体作为一种新型的绿色溶剂和稳定剂,已成功应用于制备金属纳米粒子.与传统的溶剂和稳定剂相比,它具有许多独特的物理化学性质和鲜明的优势,已引起越来越多研究者的关注.本文对近年来国内外在离子液体中制备金属纳米粒子及其催化作用的研究进行综述,并对该领域的研究前景作了展望.     

金属钝化剂的合成和应用

综述了塑料用金属钝化剂的机理、种类和合成方法,重点介绍了金属钝化剂在聚乙烯、聚丙烯和苯乙烯类聚合物中的应用。指出金属钝化剂加入填充聚烯烃后,可以延长材料的耐老化时间。     

A Rapid Synthesis of Oriented Palladium Nanoparticles by UV Irradiation

Palladium nanoparticles of average size around 8 nm have been synthesized rapidly by UV irradiation of mixture of palladium chloride and potassium oxalate solutions. A rod-shaped palladium oxalate complex has been observed as an intermediate. In the absence of potassium oxalate, no Pd nanoparticles have been observed. The synthesized Pd nanoparticles have been characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), selective area electron diffraction and energy dispersive analysis by X-rays (EDAX) analyses. XRD analysis indicates the preferential orientation of catalytically active {111} planes in Pd nanoparticles. A plausible mechanism has been proposed for the formation of anisotropic Pd nanoparticles.     

Charge Modified Porous Organic Polymer Stabilized Ultrasmall Platinum Nanoparticles for the Catalytic Dehydrogenative Coupling of Silanes with Alcohols

Catalysis Letters - Developing an ideal stabilizer to prevent the aggregation of nanoparticles is still a big challenge for the practical application of noble metal nanocatalysts. Herein, we...     

Hydrosilylation of Internal Alkynes Catalyzed by Tris‐ Imidazolium Salt‐Stabilized Palladium Nanoparticles

Palladium nanoparticles stabilized with tris‐imidazolium tetrafluoroborates catalyze the stereoselective hydrosilylation of internal alkynes in a dry inert atmosphere to give (E)‐vinylsilanes in excellent yields. In the presence of controlled amounts of water a transfer hydrogenation reaction takes place with the formation of (Z) ‐ alkenes or the corresponding alkanes.

     

超声波辅助溶胶-凝胶法制备SnO2纳米晶的研究

以SnCl4·5H2O和氨水为主原料,采用超声波辅助溶胶-凝胶法成功合成出了SnO2纳米晶,并讨论了制备过程中超声波作用时间、超声波的有无、烧结温度和表面活性剂等因素对纳米晶性能的影响。样品采用XRD,TEM进行了表征。结果表明,超声波辅助溶胶-凝胶法合成的SnO2微粒呈圆球形,粒径在20 nm左右,其中阴离子表面活性剂-柠檬酸对SnO2纳米晶的团聚能够起到很好的分散作用。     

Chirally Modified Platinum Nanoparticles Stabilized by Dendritic Core‐Multishell Architectures for the Asymmetric Hydrogenation of Ethyl Pyruvate

In this paper we present the asymmetric hydrogenation of α‐keto esters with platinum nanoparticles homogeneously stabilized in dendritic core‐multishell architectures. The main focus lies on recycling and metal leaching, because little is reported so far about these aspects. It is shown that the stabilizing polymer allows for the efficient modification of the Pt surface with the chiral alkaloid cinchonidine, thereby inducing enantioselectivity and enhancing the reaction rate in the asymmetric hydrogenation of ethyl pyruvate. After optimization of the reaction conditions 63% ee for (R)‐ethyl lactate was obtained. During recycling it was found that this value could even be increased upon ultrafiltration of the catalyst prior to use. Recycling was accomplished for 10 cycles with stable activity and enantioselectivity (∼73% ee) in the first eight runs. Aggregation of the initially well dispersed nanoparticles was observed by transmission electron microscope (TEM) analysis, leading to reduced conversion after the 8^th cycle, but metal leaching into the product has been observed only in the very first run.     

Pd Nanoparticles and Thin Films for Room Temperature Hydrogen Sensor

We report the application of palladium nanoparticles and thin films for hydrogen sensor. Electrochemically grown palladium particles with spherical shapes deposited on Si substrate and sputter deposited Pd thin films were used to detect hydrogen at room temperature. Grain size dependence of H₂ sensing behavior has been discussed for both types of Pd films. The electrochemically grown Pd nanoparticles were observed to show better hydrogen sensing response than the sputtered palladium thin films. The demonstration of size dependent room temperature H₂ sensing paves the ways to fabricate the room temperature metallic and metal–metal oxide semiconductor sensor by tuning the size of metal catalyst in mixed systems. H₂ sensing by the Pd nanostructures is attributed to the chemical and electronic sensitization mechanisms.     

电沉积碳纳米管担载金属纳米微粒复合镀层及其应用

碳纳米管因其具有独特的性能而受到越来越多的关注,其固有的特性使其成为理想的金属纳米微粒的载体。概述了电沉积法制备碳纳米管担载金属纳米微粒的工艺及其进展,同时介绍了该复合镀层在催化剂和传感器等领域的应用。     

Recent Advances in Metal Nanoparticles Stabilization into Nanopores of Montmorillonite and Their Catalytic Applications for Fine Chemicals Synthesis

Metal nanoparticles supported montmorillonite with innovative characteristics has led to a new generation of heterogeneous “nanocatalyst.” Such catalysts are superior to the conventional catalysts because of several factors like: higher surface area; higher activity; higher selectivity and longer life and thus, developing a newer type of sustainable environmentally friendly catalysts. Metal clay supported nanocatalysts may find a wide range of applications in the area of fine and bulk chemical industries, pharmaceuticals, fuel cell, petroleum refineries, environmental catalysis, and many other fields. This article summarizes the recent advances in the synthesis and characterization of metal nanoparticles supported on modified montmorillonite and their catalytic applications for fine chemicals synthesis.