银纳米材料的合成及应用的新进展

介绍了银纳米粒子的形貌的可控合成方法,概述银纳米材料在催化、光学以及抗菌领域的应用,综述了银纳米材料的最新研究成果,对其未来的发展方向进行了展望。     

金属纳米颗粒的形貌控制合成研究进展及催化应用展望

金属纳米材料的性能与其颗粒的形貌密切相关。近年来,研究人员致力于单分散的金属纳米颗粒的形貌控制合成,利用多种方法得到单一不同形貌的金属纳米颗粒。本文综述了金属纳米颗粒的形貌合成进展并展望了其在催化上的应用。     

纳米铜催化剂应用与研究进展

近年来，以开采量丰富、价格低廉的铜及铜基纳米材料的应用，特别是在催化领域和石油化工领域引起了研究者与设计者的广泛关注。运用不同的铜基纳米材料的制备工艺对铜纳米粒子的理化性质有不同的影响，研究者制备各种形貌和不同尺度的铜基纳米材料应用于催化领域。铜基纳米材料在偶合反应、催化加氢反应、氧化反应与光催化反应等领域有着广泛的应用。随着铜基纳米材料制备工艺日臻成熟，实验条件日趋温和，纳米铜基催化剂在催化领域将会有广泛的应用前景。     

不同形貌介孔二氧化硅纳米材料控制制备及应用研究进展

形貌可控的介孔二氧化硅纳米材料具有较大的比表面积、有序可调的介孔结构和稳定的理化性质,在药物输送、吸附、催化转化等领域具有良好的应用前景,近年来得到了广泛的研究.通过综述不同形貌介孔二氧化硅纳米材料的控制制备、形成机制及在不同领域的应用,指出合成过程中模板剂类型、反应温度及反应体系pH值等条件是其形貌控制的关键因素.最后,对不同形貌介孔二氧化硅纳米材料的研究重点和发展方向进行了展望.     

形貌可控的Pt纳米催化剂的制备及其应用进展

铂纳米催化剂由于其高效的还原和氧化作用,在催化和电催化领域的应用非常的广泛.在反应中除了尺寸外,Pt纳米晶体的形貌对催化和电催化的活性和选择性也起到了关键的作用.调变合成单一形貌催化剂的条件,如稳定剂、还原剂和表面活性剂等,对于调控纳米粒子的形貌至关重要.目前形貌可控的铂纳米催化剂已被应用到加氢、氧化和Suzuiki偶...     

一维贵金属纳米材料的控制合成与应用

一维纳米材料具有优良的尺寸效应,一维贵金属材料表现出不同于相应块体材料的特殊物理化学性能。本文以一维贵金属纳米结构的合成方法和机理为探讨重点,总结了近年来国内外用于控制合成一维贵金属纳米材料的主要方法,包括模板法、多元醇还原法、化学电沉积法以及金属催化还原法。着重以金属银、钯为例,介绍了其形状可控的一维纳米结构的生长机理,并以金、银等一维纳米材料为例介绍了其一维纳米结构在功能材料以及生物医学等领域的应用前景。指出建立一维金属纳米结构制备科学的新理论、新方法及其成核生长动力学模型是进一步研究的方向。     

钯纳米颗粒制备方法的研究进展

钯纳米颗粒近年来在偶联反应、催化加氢和氧化等反应中被广泛应用,并且被用于储氢材料和燃料电池催化电极等领域。在多相催化领域中,纳米技术能够通过改变金属钯的尺寸和形貌来提高其利用率和催化活性,而制备方法是决定钯纳米颗粒性能的关键。从钯纳米颗粒在催化领域的应用方面对近年来钯纳米催化剂的制备方法进行了综述。     

形貌与晶相可控的微纳米金属氧化物提升高能氧化剂热分解性能的研究进展（英文）

综述了近期关于金属氧化物的形貌可控合成以及它们作为燃烧催化剂的应用方面的一些研究。简要介绍了微纳米材料的可控合成,讨论了几种典型的具有特殊形貌金属氧化物纳米材料的结构特征,以及它们在含能化合物催化热分解过程中所表现出的良好催化性能。最后,对形貌及晶相可控的纳米燃烧催化剂未来的发展趋势以及其在固体复合推进剂应用方面所能够发挥的重要作用进行了总结和展望。附参考文献57篇。     

沸石和介孔氧化硅纳米材料的绿色合成及其在环境领域中的应用

综述了近年来纳米沸石和介孔氧化硅纳米材料的绿色合成方法以及这些材料在环境领域中的应用。重点讨论了这些材料的模板剂循环利用合成法、无模板剂合成法、离子液体合成法、无溶剂合成法以及微波加热合成法等绿色合成技术和方法;同时论述了纳米沸石和介孔氧化硅纳米材料在环境催化以及环境污染物吸附等方面的应用。最后对纳米沸石及介孔氧化硅纳米材料的合成技术新发展和新应用进行了展望。     

PVP导向ZnO纳米线、纳米棒的可控溶剂热合成及其生长机理研究

本文采用强碱性的溶剂热法,通过调控反应温度、时间、反应物投料比、特别是添加剂等影响因素,可控合成了两种不同形貌的一维ZnO纳米材料.利用透射电镜(TEM)和扫描电镜(SEM)研究了不同影响因素对ZnO产物形貌的影响.着重分析了添加剂聚乙烯吡咯烷酮(PVP)与纳米ZnO或其生长基元的络合作用,及其对纳米ZnO形貌的控制作用,并总结出强碱性溶剂热合成中反应温度、体系压强和pH值对ZnO产物形貌的作用机理.     

Aqueous-Phase Synthesis of Silver Nanodiscs and Nanorods in Methyl Cellulose Matrix: Photophysical Study and Simulation of UV–Vis Extinction Spectra Using DDA Method

We present a very simple and effective way for the synthesis of tunable coloured silver sols having different morphologies. The procedure is based on the seed-mediated growth approach where methyl cellulose (MC) has been used as soft-template in the growth solution. Nanostructures of varying morphologies as well as colour of the silver sols are controlled by altering the concentration of citrate in the growth solution. Similar to the polymers in the solution, citrate ions also dynamically adsorbed on the growing silver nanoparticles and promote one (1-D) and two-dimensional (2-D) growth of nanoparticles. Silver nanostructures are characterized using UV–vis and HR-TEM spectroscopic study. Simulation of the UV–vis extinction spectra of our synthesized silver nanostructures has been carried out using discrete dipole approximation (DDA) method.     

Antibacterial latex foams coated with biologically synthesized silver nanoparticles using Magnolia kobus leaf extract

Silver nanoparticles are used in many industries due to their disinfection and antibacterial properties. Biological methods of nanoparticle synthesis have been suggested as possible ecofriendly alternatives to chemical and physical methods. In this study, biologically synthesized silver nanoparticles using Magnolia kobus leaf extract were coated on the surface of latex foam products using dip coating (exposure to nanoparticle solution) or ultrasonic treatment. SEM image of the treated foam showed that silver nanoparticles were uniformly coated on the surface of latex foam. Antibacterial properties were tested by counting viable Escherichia coli cells after 24 h growth in shake flask cultures containing latex foams coated with silver nanoparticles. Foams coated with silver nanoparticles showed higher antibacterial activities compared with foams untreated. Smaller silver nanoparticles synthesized at higher temperature showed higher antibacterial activity due to the larger specific surface area and higher content of silver nanoparticles. The growth of E. coli decreased with increasing the concentration of silver nanoparticles. Ultrasonic treatment showed higher adsorption and lower desorption of silver nanoparticles to and from the foams compared with dip coating, resulting in higher antibacterial activity.     

银纳米颗粒及其负载TiO2的制备与应用研究

采用液相化学还原法和溶胶-凝胶法,制备得到形貌各异的银颗粒及其负载的TiO2复合材料。透射电镜（TEM）结果显示,可以制备得到表面光滑,形状均匀一致的球形、三角形和四方形银纳米颗粒;X射线衍射（XRD）结果表明,银纳米颗粒晶体结构属于立方品系;利用傅立叶变换红外光谱仪（FT—IR）研究了聚乙烯吡咯啉酮（PVP）在生成不同形貌银纳米颗粒的化学反应中的作用机理;Ag／TiO2复合材料的X射线衍射能谱（XPS）结果表明,负载的银主要以零价态形式存在于TiO2的表面;研究了不同形貌银纳米颗粒的抗菌性能以及Ag／TiO2复合材料的光催化脱色亚甲基蓝的活性,结果表明,所制备的银纳米颗粒杀菌率均在99％以上;银负载到TiO2后,Ag／TiO2复合材料的光催化活性得到明显提高。其中,球形银负载的Ag／TiO2复合光催化剂活性最好。     

Construction of chitosan-carboxymethyl β-cyclodextrin silver nanocomposite hydrogel to improve antibacterial activity

Silver nanoparticles (AgNPs) are widely used in various fields but their physical and chemical instability have limited their applications. The present work demonstrates a novel approach for the synthesis and stabilising of AgNPs. Chitosan and carboxymethyl β-cyclodextrin were used to prepare a polymeric hydrogel with glutaraldehyde as cross-linker. As a result, AgNPs were formed with very high dispersion and stability in the hydrogel structure. It is possible to create nanoreactors to produce AgNPs by adding CM-βCD to the structure of the hydrogel. Fourier transform infrared (FTIR) analysis was employed to characterise the Cs-CM-βCD hydrogel. The morphologies of pure Cs-CM-βCD hydrogel and silver nanocomposite were observed by scanning electron microscopy. Moreover, UV–VIS spectroscopy and X-ray diffraction were used to characterise the prepared silver nanocomposite. In addition, the antibacterial properties of these silver nanocomposite hydrogels were investigated against Staphylococcus aureus (Gram positive) and Escherichia coli (Gram negative).     

A new and convenient route to polyacrylate/silver nanocomposites by light-induced cross-linking polymerization

A new method for the preparation of silver nanoparticles/polymer nanocomposite materials by UV-radiation curing of multifunctional acrylate monomers has been developed. Silver nanoparticles possessing an average diameter of 6.6 nm were first prepared by chemical reduction of silver nitrate with t-BuONa-activated sodium hydride in THF. Transmission electron microscopy (TEM) and size distribution analysis revealed that silver(0) nanoparticles remained well-dispersed in acrylic formulations composed of tetrahydrofurfuryl acrylate, polyurethane acrylate and polyethylene glycol 400 diacrylate. The curing process was followed quantitatively by infrared spectroscopy through the decrease of the IR bands characteristic of the functional groups upon UV exposure. The viscoelastic properties of the nanocomposite photopolymer were monitored by dynamic mechanical analysis (DMA). Silver nanoparticles were found to have no detrimental effect on the photopolymerization kinetics and the incorporation of metal nanoparticles allowed to reduce the gloss of UV-cured coatings. An increase of the diameter of silver nanoparticles to 20 nm was observed during the curing process.     

Antibacterial performance of Ag nanoparticles and AgGO nanocomposites prepared via rapid microwave-assisted synthesis method

Silver nanoparticles and silver-graphene oxide nanocomposites were fabricated using a rapid and green microwave irradiation synthesis method. Silver nanoparticles with narrow size distribution were formed under microwave irradiation for both samples. The silver nanoparticles were distributed randomly on the surface of graphene oxide. The Fourier transform infrared and thermogravimetry analysis results showed that the graphene oxide for the AgNP-graphene oxide (AgGO) sample was partially reduced during the in situ synthesis of silver nanoparticles. Both silver nanoparticles and AgGO nanocomposites exhibited stronger antibacterial properties against Gram-negative bacteria (Salmonella typhi and Escherichia coli) than against Gram-positive bacteria (Staphyloccocus aureus and Staphyloccocus epidermidis). The AgGO nanocomposites consisting of approximately 40 wt.% silver can achieve antibacterial performance comparable to that of neat silver nanoparticles.     

Ag/P(St-MMA)纳米复合高分子微球固定化青霉素酰化酶的研究

通过溶剂热法和无皂乳液聚合相结合,制备了P(St-MMA)高分子纳米微球.并以吸附沉积的方式在其表面沉积了Ag金属纳米粒子,最后将青霉素酰化酶共价连接在微球表面.初步研究了微球直径、银的质量分数等因素对固定化酶活力的影响.结果显示随着微球直径减小,固定化酶的偶联率和活力逐渐增加;银纳米粒子最多将固定化酶的偶联率和活力分别提高了42%和72%,固定化酶的最大表观活力(以干重记)达到了1 869 u/g,明显高于其它高分子载体固定化青霉素酰化酶的活力;实验证明银纳米粒子在青霉素水解过程中没有催化活力,但能大大提高青霉素酰化酶的催化活力.     

Direct patterning of silver particles on porous silicon by inkjet printing of a silver salt via in-situ reduction

ABSTRACT: We have developed a method for obtaining a direct pattern of silver nanoparticles (NPs) on porous silicon (p-Si) by means of inkjet printing (IjP) of a silver salt. Silver NPs were obtained by p-Si mediated in-situ reduction of Ag+ cations using solutions based on AgNO3 which were directly printed on p-Si according to specific geometries and process parameters. The main difference with respect to existing literature is that normally, inkjet printing is applied to silver (metal) NP suspensions, while in our experiment the NPs are formed after jetting the solution on the reactive substrate. We performed both optical and scanning electron microscopes on the NPs traces, correlating the morphology features with the IjP parameters, giving an insight on the synthesis kinetics. The patterned NPs show good performances as SERS substrates.     

Layer-dependent morphologies of silver on n-layer graphene

The distributions of sizes of silver nanoparticles that were deposited on monolayer, bilayer, and trilayer graphene films were observed. Deposition was carried out by thermal evaporation and the graphene films, placed on SiO₂/Si substrates, were obtained by the mechanical splitting of graphite. Before the deposition, optical microscopy and Raman spectroscopy were utilized to identify the number of the graphene layers. After the deposition, scanning electron microscopy was used to observe the morphologies of the particles. Systematic analysis revealed that the average sizes of the nanoparticles increased with the number of graphene layers. The density of nanoparticles decreased as the number of graphene layers increased, revealing a large variation in the surface diffusion strength of nanoparticles on the different substrates. The mechanisms of formation of these layer-dependent morphologies of silver on n-layer graphene are related to the surface free energy and surface diffusion of the n-layer graphene. The effect of the substrate such as SiO₂/Si was investigated by fabricating suspended graphene, and the size and density were similar to those of supported graphene. Based on a comparison of the results, the different morphologies of the silver nanoparticles on different graphene layers were theorized to be caused only by the variation of the diffusion barriers with the number of layers of graphene.