Synthesis and Characterization of Dendrimer-Encapsulated Iron and Iron-Oxide Nanoparticles

In this paper, a series of iron (Fe) containing nanoparticles were prepared by employing PAMAM (Poly(amidoamine), dendrimers with different generations (G0?CG3) as templates and sodium borohydride as a reducing agent. The products have been characterized by TEM, FT-IR, XRD, VSM, TGA, and XPS. XRD analysis reveal low crystallinity of formed particles within the dendrimers, however, crystallinity of the nanoparticles was observed to increase with increasing generation of dendrimers. Dominant phases were determined as magnetite (Fe₃O₄ or maghemite, ??-Fe₂O₃). XPS analysis revealed the chemical composition of nanoparticles as iron oxide which indicated the oxidation of Fe species subsequent to the reduction process, in agreement with XRD analysis. The magnetization curves have superparamagnetic nonhysteretic characteristic at lower fields and with nonsaturation characteristic at high fields. Magnetic evaluation of samples with the 20:1?molar ratio of Fe:PAMAM showed decreasing superparamagnetic character and decreasing saturation magnetisation with increasing generation of dendrimers.     

Continuous Synthesis of Hollow High-Entropy Nanoparticles for Energy and Catalysis Applications

Mixing multimetallic elements in hollow-structured nanoparticles is a promising strategy for the synthesis of highly efficient and cost-effective catalysts. However, the synthesis of multimetallic hollow nanoparticles is limited to two or three elements due to the difficulties in morphology control under the harsh alloying conditions. Herein, the rapid and continuous synthesis of hollow high-entropy-alloy (HEA) nanoparticles using a continuous “droplet-to-particle” method is reported. The formation of these hollow HEA nanoparticles is enabled through the decomposition of a gas-blowing agent in which a large amount of gas is produced in situ to “puff” the droplet during heating, followed by decomposition of the metal salt precursors and nucleation/growth of multimetallic particles. The high active sites per mass ratio of such hollow HEA nanoparticles makes them promising candidates for energy and electrocatalysis applications. As a proof-of-concept, it is demonstrated that these materials can be applied as the cathode catalyst for Li–O₂ battery operations with a record-high current density per catalyst mass loading of 2000 mA g_cat.⁻¹, as well as good stability and durable catalytic activity. This work offers a viable strategy for the continuous manufacturing of hollow HEA nanomaterials that can find broad applications in energy and catalysis.     

From Galvanic to Anti‐Galvanic Synthesis of Bimetallic Nanoparticles and Applications in Catalysis,Sensing, and Materials Science

The properties of two alloyed metals have been known since the Bronze Age to outperform those of a single metal. How alloying and mixing metals applies to the nanoworld is now attracting considerable attention. The galvanic process, which is more than two centuries old and involves the reduction of a noble‐metal cation by a less noble metal, has not only been used in technological processes, but also in the design of nanomaterials for the synthesis of bimetallic transition‐metal nanoparticles. The background and nanoscience applications of the galvanic reactions (GRs) are reviewed here, in particular with emphasis on recent progress in bimetallic catalysis. Very recently, new reactions have been discovered with nanomaterials that contradict the galvanic principle, and these reactions, called anti‐galvanic reactions (AGRs), are now attracting much interest for their mechanistic, synthetic, catalytic, and sensor aspects. The second part of the review deals with these AGRs and compares GRs and AGRs, including the intriguing AGRs mechanism and the first applications.     

Group IV Nanoparticles: Synthesis,Properties, and Biological Applications

In this review, the emerging roles of group IV nanoparticles including silicon, diamond, silicon carbide, and germanium are summarized and discussed from the perspective of biologists, engineers, and medical practitioners. The synthesis, properties, and biological applications of these new nanomaterials have attracted great interest in the past few years. They have gradually evolved into promising biomaterials due to their innate biocompatibility; toxic ions are not released when they are used in vitro or in vivo, and their wide fluorescence spectral regions span the near‐infrared, visible, and near‐ultraviolet ranges. Additionally, they generally have good resistance against photobleaching and have lifetimes on the order of nanoseconds to microseconds, which are suitable for bioimaging. Some of the materials possess unique mechanical, chemical, or physical properties, such as ultrachemical and thermal stability, high hardness, high photostability, and no blinking. Recent data have revealed the superiority of these nanoparticles in biological imaging and drug delivery.     

Facile Synthesis and Characterization of Fe/FeS Nanoparticles for Environmental Applications

Multicomponent nanoparticles containing two or more different types of functionalities show unique physical and chemical properties, leading to significantly enhanced performance. In this study, we have developed a new one-pot method to prepare Fe/FeS nanoparticles using dithionite at room temperature. The FeS precipitates on the Fe surface are formed by the interaction between dissolved iron species and hydrogen sulfide, one of the decomposition products of dithionite in solution. The resulting Fe/FeS nanoparticles have high surface area, good electrical conductivity, and strong magnetic responsivity. In addition, the Fe/FeS shows a much higher reactivity toward contaminants than the pure Fe nanoparticles. The above synthesized nanoparticles are successfully applied for the rapid removal of trichloroethylene (TCE) from water. The study reveals that Fe/FeS nanoparticles are a promising candidate for the efficient removal of pollutants.     

掺锶羟基磷灰石纳米颗粒的合成、表征及模拟研究

锶(Sr)掺杂羟基磷灰石(HA)在生物材料中得到广泛应用。在此研究中, 使用水热合成的方法制备HA和Sr掺杂HA的纳米颗粒。通过实验和计算机模拟的方法研究Sr掺杂对HA化学成分、结晶度、晶格参数、形貌和形成能的影响。实验结果表明, Sr掺杂后的HA纳米颗粒晶格参数和晶体尺寸增大。随着Sr离子浓度的增加, Sr 掺杂HA的纳米颗粒的结晶度没有显著变化。模拟结果验证了实验得到的Sr 掺杂HA纳米颗粒晶格参数的准确性, 且进一步表明Sr 离子掺杂后纳米颗粒的形成能较低, 结构更稳定。当Sr掺杂浓度为10%时, Sr掺杂的优先位点是Ca(1); Sr掺杂浓度为50%时, Sr混合掺杂到Ca(1)和Ca(2)位点为更优先的掺杂模式。     

Mesoporous Organosilica Hollow Nanoparticles: Synthesis and Applications

Hollow periodic mesoporous organosilicas (PMOs) with molecularly homogeneous organic functional groups in the inorganic pore walls are attracting more and more attention due to the high surface areas, tunable pore sizes, low densities, large cavities in the center, permeable thin shells, and versatile organic–inorganic hybrid frameworks, which make them promising in a variety of applications including adsorption, catalysis, drug delivery, and nanotheranostics. Herein, recent advances in the synthesis of hollow PMO nanoparticles with various organic moieties are summarized, and the mechanism and new insights of synthesis approaches, including hard‐core templating methods, liquid‐interface assembly methods, and the interfacial reassembly and transformation strategy are discussed in‐depth. Meanwhile, the design principles, properties, and synthetic strategies for some smart hollow architectures such as multishelled hollow PMOs, yolk–shell structured PMOs, and nonspherical hollow PMOs are discussed. Moreover, the typical applications of hollow PMO nanomaterials as nanoreactors for chemical transformations and nanoplatforms for biomedicine are summarized. Finally, the challenges and prospects for the future development of hollow PMOs are described.     

Black Phosphorus Nanosheets: Synthesis,Characterization and Applications

Black phosphorus (BP) is an emerging two‐dimensional (2D) material with a natural bandgap, which has unique anisotropy and extraordinary physical properties. Due to its puckered structure, BP exhibits strong in‐plane anisotropy unlike other layered materials. The bandgap tunability of BP enables a wide range of ultrafast electronics and high frequency optoelectronic applications ranging from telecommunications to thermal imaging covering the nearly entire electromagnetic spectrum, whereas no other 2D material has this functionality. Here, recent advances in the synthesis, fabrication, anisotropic physical properties, and BP‐based devices including field effect transistors (FETs) and photodetectors, are discussed. Recent passivation approaches to address the degradation of BP, which is one of the main challenges to bring this material into real world applications, are also introduced. Finally, a comment is made on the recent developments in other emerging applications, future outlook and challenges ahead in BP research.     

Moving Frontiers in Transition Metal Catalysis: Synthesis,Characterization and Modeling

Nanosized transition metal particles are important materials in catalysis with a key role not only in academic research but also in many processes with industrial and societal relevance. Although small improvements in catalytic properties can lead to significant economic and environmental impacts, it is only now that knowledge‐based design of such materials is emerging, partly because the understanding of catalytic mechanisms on nanoparticle surfaces is increasingly improving. A knowledge‐based design requires bottom‐up synthesis of well‐defined model catalysts, an understanding of the catalytic nanomaterials “at work” (operando), and both a detailed understanding and a prediction by theoretical methods. This article reports on progress in colloidal synthesis of transition metal nanoparticles for preparation of model catalysts to close the materials gap between the discoveries of fundamental surface science and industrial application. The transition metal particles, however, often undergo extensive transformations when applied to the catalytic process and much progress has recently been achieved operando characterization techniques under relevant reaction conditions. They allow better understanding of size/structure–activity correlations in these systems. Moreover, the growth of computing power and the improvement of theoretical methods uncover mechanisms on nanoparticles and have recently predicted highly active particles for CO/CO₂ hydrogenation or direct H₂O₂ synthesis.     

CuMgAl类水滑石的合成、表征及催化性能研究

采用共沉淀法制备了不同配比的CuMgAl类水滑石化合物,通过XRD、IR、DTA分析表征了合成的化合物,并以其为前驱体经煅烧得到的CuO-MgO-Al2O3复合氧化物催化剂,在丙酮气相加氢一步合成MIBK反应中测试了其催化活性.结果表明:随着M2 /M3 比的增加,合成的类水滑石晶型越完整,层间距也随之加大,热稳定性降低;类水滑石中Cu2 含量的增加亦导致层板间距加大,热稳定性也随之降低;催化活性测试结果表明,在催化剂中Cu:Mg:Al=4:16:10时MIBK的选择性最佳,达38.61%.     

Synthesis,Functionalization, and Biomedical Applications of Multifunctional Magnetic Nanoparticles

Synthesis of multifunctional magnetic nanoparticles (MFMNPs) is one of the most active research areas in advanced materials. MFMNPs that have magnetic properties and other functionalities have been demonstrated to show great promise as multimodality imaging probes. Their multifunctional surfaces also allow rational conjugations of biological and drug molecules, making it possible to achieve target‐specific diagnostics and therapeutics. This review first outlines the synthesis of MNPs of metal oxides and alloys and then focuses on recent developments in the fabrication of MFMNPs of core/shell, dumbbell, and composite hybrid type. It also summarizes the general strategies applied for NP surface functionalization. The review further highlights some exciting examples of these MFMNPs for multimodality imaging and for target‐specific drug/gene delivery applications.     

Synthesis,Characterization and Biocompatibility of Potassium Ferrite Nanoparticles简

In the present study,morphology,size distribution,structure,biocompatibility and magnetic properties of potassium ferrite nanoparticles(KFeO_2 NPs),synthesized by conventional sol—gel method have been reported.The formation of spherical nanoparticles with orthorhombic structure has been confirmed by scanning electron microscopy and X-ray diffraction.The particle size,as obtained by transmission electron microscopy has been found to be in the range of 4—7 nm.Further,the size distribution has been scrutinized using Analyse-it software,where a platykurtic feature in the size distribution was observed.Fourier transform-infrared spectroscopy and thermogravimetric analysis showed the formation of metal(Fe,K) bonds at Neel temperature of 337℃.Vibrating sample magnetometer analysis revealed the superparamagnetic behaviour of the synthesized KFeO_2NPs,with saturation magnetization of 25.72 emu/g.In vitro cytotoxicity test,using MTT assay,on T cell lines(Jurkat cells) showed that KFeO_2 NPs are biocompatible at a particle concentration of 100 |j.g/ml.     

Synthesis and Biomedical Applications of Copper Sulfide Nanoparticles: From Sensors to Theranostics

Copper sulfide (CuS) nanoparticles have attracted increasing attention from biomedical researchers across the globe, because of their intriguing properties which have been mainly explored for energy‐ and catalysis‐related applications to date. This focused review article aims to summarize the recent progress made in the synthesis and biomedical applications of various CuS nanoparticles. After a brief introduction to CuS nanoparticles in the first section, we will provide a concise outline of the various synthetic routes to obtain different morphologies of CuS nanoparticles, which can influence their properties and potential applications. CuS nanoparticles have found broad applications in vitro, especially in the detection of biomolecules, chemicals, and pathogens which will be illustrated in detail. The in vivo uses of CuS nanoparticles have also been investigated in preclinical studies, including molecular imaging with various techniques, cancer therapy based on the photothermal properties of CuS, as well as drug delivery and theranostic applications. Research on CuS nanoparticles will continue to thrive over the next decade, and tremendous opportunities lie ahead for potential biomedical/clinical applications of CuS nanoparticles.     

One‐Dimensional Nanostructures: Synthesis,Characterization, and Applications

This article provides a comprehensive review of current research activities that concentrate on one‐dimensional (1D) nanostructures—wires, rods, belts, and tubes—whose lateral dimensions fall anywhere in the range of 1 to 100 nm. We devote the most attention to 1D nanostructures that have been synthesized in relatively copious quantities using chemical methods. We begin this article with an overview of synthetic strategies that have been exploited to achieve 1D growth. We then elaborate on these approaches in the following four sections: i) anisotropic growth dictated by the crystallographic structure of a solid material; ii) anisotropic growth confined and directed by various templates; iii) anisotropic growth kinetically controlled by supersaturation or through the use of an appropriate capping reagent; and iv) new concepts not yet fully demonstrated, but with long‐term potential in generating 1D nanostructures. Following is a discussion of techniques for generating various types of important heterostructured nanowires. By the end of this article, we highlight a range of unique properties (e.g., thermal, mechanical, electronic, optoelectronic, optical, nonlinear optical, and field emission) associated with different types of 1D nanostructures. We also briefly discuss a number of methods potentially useful for assembling 1D nanostructures into functional devices based on crossbar junctions, and complex architectures such as 2D and 3D periodic lattices. We conclude this review with personal perspectives on the directions towards which future research on this new class of nanostructured materials might be directed.     

Synthesis and Characterization of Sphere-like Pt Nanoparticles Supported on DWCNT/WO_3 Nanorods with Electrocatalytic Activity

Tungsten oxide(WO3) nanorods, which were used to load platinum(Pt) nanoparticles, were investigated. H2WO4 nanorods with diameters from 10 to 50 nm were obtained when tungsten precursor was added into homogenous double-walled carbon nanotubes(DWCNT) and ethylene glycol(EG) solution.Nanosized rod-like WO3 were achieved after calcination of the DWCNT/H2WO4 composite. Sphere-like Pt nanoparticles were loaded on the surface of the nanorods by EG in-situ reduction. Pt particles were isolated by DWCNT/WO3 nanorods and secondary accumulation could be prevented when Pt particles appeared in the DWCNT/WO3 nanorod/EG dispersion solution. Therefore, Pt nanoparticles with mean diameters of 2–6 nm could be obtained. Pt-deposited on DWCNT/WO3 nanorods exhibited high electrochemical activity, which could facilitate the low-cost mass production of Pt catalyst.     

Synthesis and Characterization of Ferromagnetic Nickel Nanoparticles

Nickel nanoparticles on mass production scale have been prepared using a modified polyol process with Ni(CH₃COO)₂?4H₂O, NaOH, 1,2 propandiol and hydrazinium hydroxide (N₂H₄?H₂O). A?mixture of face centered cubic (fcc) metallic nickel nanoparticles with 12 nm diameter were obtained. We have experimentally studied the structure of nanoparticle by X-ray and Scanning Electron Microscopy (SEM, EDS). The magnetic properties of the prepared Ni film have been studied by Ferromagnetic Resonance (FMR) technique, Vibrating Sample Magnetometer (VSM) and Vector Network Analyzer (VNA). The effective g-factor and magnetic anisotropy constant were determined as g _eff=2.25 and K _eff=85?Oe, respectively.     

Ag_2S纳米粒子的合成与表征

以油酸钠为表面活性剂、硝酸银和硫脲为反应物,在甲苯-水两相界面处合成了Ag_2S纳米粒子。采用紫外-可见吸收光谱(UV-Vis)、透射电子显微镜(TEM)和广角X射线衍射(WAXD)等方法对Ag_2S纳米粒子的光学性质、形貌及晶体结构进行了表征。结果表明,通过改变甲苯-水两相界面反应体系的条件,可以得到粒子尺寸窄分布的Ag_2S纳米粒子;WAXD测定表明所合成的Ag_2S纳米粒子具有单斜结构。     

Synthesis and Characterization of Fucan-Coated Cobalt Ferrite Nanoparticles

This work presents some results of the synthesis and structural, microstructural, and magnetic characterization of fucan coated cobalt ferrite nanoparticles prepared by using a modified coprecipitation method. Aqueous suspensions of magnetic particles were prepared by coprecipitation of Fe(III) and Co(II) in the presence of NaOH, acid oleic and fucan polymer. The samples were characterized by X-ray diffraction (XRD), electron scanning microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), accelerated surface area, and porosimetry (ASAP/BET-Brunauer-Emmet-Teller) determination and magnetization measurements. Our results reveal that both uncoated and fucan polysaccharide coated CoFe₂O₄ nanoparticles were successfully obtained. The nanoparticles present sizes between 7 to 20 nm and saturation magnetization of the order of 40 emu/g. The nanoparticles thus obtained are suitable for future applications as a solid support for enzymes immobilization and other biotechnology applications.