Synthesis Of Advanced Materials Research Articles

X-rays and magnetism

Magnetism is among the most active and attractive areas in modern solid state physics because of intriguing phenomena interesting to fundamental research and a manifold of technological applications. State-of-the-art synthesis of advanced magnetic materials, e.g. in hybrid structures paves the way to new functionalities.To characterize modern magnetic materials and the associated magnetic phenomena, polarized x-rays have emerged as unique probes due to their specific interaction with magnetic materials. A large variety of spectroscopic and microscopic techniques have been developed to quantify in an element, valence and site-sensitive way properties of ferro-, ferri-, and antiferromagnetic systems, such as spin and orbital moments, and to image nanoscale spin textures and their dynamics with sub-ns time and almost 10 nm spatial resolution. The enormous intensity of x-rays and their degree of coherence at next generation x-ray facilities will open the fsec time window to magnetic studies addressing fundamental time scales in magnetism with nanometer spatial resolution.This review will give an introduction into contemporary topics of nanoscale magnetic materials and provide an overview of analytical spectroscopy and microscopy tools based on x-ray dichroism effects. Selected examples of current research will demonstrate the potential and future directions of these techniques.

Encapsulating Inorganic Acetylene, HBNH, Using Flanking Coordinative Interactions.

A stable donor-acceptor coordination complex of the elusive parent inorganic iminoborane HBNH (a structural analogue of acetylene) is reported. This species was generated via thermally induced N2 elimination/1,2-H migration from a hydrido(azido)borane adduct NHC⋅BH2N3 (NHC=N-heterocyclic carbene) in the presence of a fluorinated triarylborane. The mechanism of this process was also investigated by computational and isotopic labeling studies. This transformation represents a new and potentially modular route to unsaturated inorganic building blocks for advanced material synthesis.

Modification of ICHTJ sol gel process for preparation of medium sized ceramic spheres (Ø

In the Sol–Gel Laboratory at the Institute of Nuclear Chemistry and Technology (INCT), studies of synthesis of various advanced ceramic materials by the sol–gel method have been carried out for 50 years. The ceramics products, such as metal oxides, homogeneous mixtures of metal oxides, cermetals and metals, were obtained in various shapes, as irregular powders, monoliths, coatings, fibers or spherical particles with various diameters. A new method using a water-in-oil technique – the ICHTJ Process (INCT in English) was elaborated to synthesize spherical particles of metal oxide or mixture of metal oxides, with diameters below 100µm. Through years, the method has been evaluated and optimized. Prepared sol solutions of metal cations are emulsified in 2-ethylhexanol-1 containing 1 volume % of the surfactant sorbitol monooleate. Drops of emulsion are gelled by extracting their water with this organic solvent. The main parameters e.g. flow rate; gelation time, syringe, sol solution etc. that have a strong influence on the optimization of the synthesis method and features of the spherical particles are described in this article through an example of synthesis of uranium oxycarbide – mixture of uranium dioxide with uranium carbide.

ChemInform Abstract: Recent Approaches for the Direct Use of Elemental Sulfur in the Synthesis and Processing of Advanced Materials

AbstractReview: [recent physical processing methods and synthetic procedures involving the direct use of elemental sulfur; 93 refs.

ChemInform Abstract: The Impact of Copper‐Catalyzed Alkyne‐Azide 1,3‐Dipolar Cycloaddition in Fullerene Chemistry

AbstractReview: [progress on the development of clickable fullerene building blocks and their application to the synthesis of new advanced materials and bioactive compounds; 75 refs.

Multiphase flow in microfluidic devices

Recent years have witnessed the rapid development of microfluidic technology and microfluidic devices as a multi-disciplinary research field. Compared to conventional methods, microfluidic technology enables us to precisely manipulate the small volume of multiphase fluids for chemical analysis, advanced materials synthesis, protein crystalliza-tion, single-cell cultivation and detection, information processing, etc. In this paper, we review the multiphase flow phenomena in microfluidic devices, summarize the fluid mechan-ics involved, describe various methods to achieve multiphase microfluidic flow, and analyze the state-of-the-art of applications and challenges in this field. Finally, numerical simulation methods and experimental measurement techniques for multiphase microflows are provided. Opportunities for future research and application of microfluidic devices are suggested.

Recent Approaches for the Direct Use of Elemental Sulfur in the Synthesis and Processing of Advanced Materials

Elemental sulfur is an abundant and inexpensive material obtained as a by-product of natural-gas and petroleum refining operations. Recently, the need for the development of new energy-storage systems brought into light the potential of sulfur as a high-capacity cathode material in secondary batteries. Sulfur-containing materials were also shown to have useful IR optical properties. These developments coupled with growing environmental concerns related to the global production of excess elemental sulfur have led to a keen interest in its utilization as a feedstock in materials applications. This Minireview focuses on the recent developments on physical and chemical methods for directly processing elemental sulfur to produce functional composites and polymers.

High-yield microwave synthesis of layered Y2(OH)5NO3·xH2O materials

A novel, facile, and versatile microwave-assisted method of high-yield synthesis of layered rare earth hydroxo compounds (LRHs) is proposed. Layered yttrium hydroxonitrates synthesized by the microwave-assisted technique crystallize in the form of thin hexagonal plates aggregated into spheroidal particles. Depending on the conditions of microwave-assisted hydrothermal synthesis, the formation of several phases differing in interplanar spacing along the [00l] direction is possible. The materials obtained are shown to possess good anion-exchange properties. This work provides a route to large-scale synthesis of LRH-based advanced materials.

Negishi coupling in the synthesis of advanced electronic, optical, electrochemical, and magnetic materials

Negishi coupling is an efficient and versatile tool for selective C–C bond formation in the synthesis of organic electronic, optical, electrochemical, and magnetic materials.

Non-chain autoacceleration of SHS wave in conditions of rotation

Analyzed was the behavior an aluminothermic SHS system in a rotating heat-insulated cylindrical reactor. Formulated is a model taking account interaction of centrifugal d’Alambert forces with Coriolis forces within a narrow melt-containing combustion zone. The penetration of centrifugally accelerated hot product particles into the fresh mixture was found capable of initiating, at some certain conditions, SHS reactions without external ignition unit. The phenomenon can be used as the basis for designing a new SHS process for synthesis of new advanced materials in conditions of rotation.

Review—Advanced Carbon-Supported Organic Electrode Materials for Lithium (Sodium)-Ion Batteries

Electroactive organic compounds represent one of the most promising electrode materials for the next generation of green and sustainable lithium (sodium) ion batteries (LIBs/SIBs). However, most organic electrode materials are plagued by high solubility in organic electrolytes and poor electrical conductivity, which have severely impeded their practical applications. Among various strategies to improve their electrochemical performance, introducing conductive carbon into organic materials to form composite electrodes offers the possibility to simultaneously solve the two problems. In this paper, we provide an overview of recent development in the design, synthesis, and application of advanced carbon-supported organic electrode materials for LIBs/SIBs. In such systems, organic component mainly contributes to the charge storage, while carbon matrix facilitates the electron transfer and suppresses the dissolution of the active materials. We mainly focus on representative composites with carbon matrix of fibers, nanotubes (CNTs), graphene, and porous structures. We especially highlight the employment of CNTs and graphene as conductive carbon substrates for organic electrode materials due to their high conductivity, huge surface area, and excellent flexibility. The elegant design of organic-carbon composite should promote the practical applications of organic electrode materials for LIBs/SIBs.

Thermodynamic stability of high phosphorus concentration in silicon nanostructures.

Doping of Si nanocrystals (NCs) has been the subject of a strong experimental and theoretical debate for more than a decade. A major difficulty in the understanding of dopant incorporation at the nanoscale is related to the fact that theoretical calculations usually refer to thermodynamic equilibrium conditions, whereas, from the experimental point of view, impurity incorporation is commonly performed during NC formation. This latter circumstance makes impossible to experimentally decouple equilibrium properties from kinetic effects. In this report, we approach the problem by introducing the dopants into the Si NCs, from a spatially separated dopant source. We induce a P diffusion flux to interact with the already-formed and stable Si NCs embedded in SiO2, maintaining the system very close to the thermodynamic equilibrium. Combining advanced material synthesis, multi-technique experimental quantification and simulations of diffusion profiles with a rate-equation model, we demonstrate that a high P concentration (above the P solid solubility in bulk Si) within Si NCs embedded in a SiO2 matrix corresponds to an equilibrium property of the system. Trapping within the Si NCs embedded in a SiO2 matrix is essentially diffusion limited with no additional energy barrier, whereas de-trapping is prevented by a binding energy of 0.9 eV, in excellent agreement with recent theoretical findings that highlighted the impact of different surface terminations (H- or O-terminated NCs) on the stability of the incorporated P atoms.

Macroscopic/Mesoscopic Computational Materials Science Modeling and Engineering

The goal of this special issue is to provide the platform for international discussion and exchange of information/ experience on the simulation of phenomena in and characteristics of materials at macroscopic and mesoscopic scales. In particular, these publications are the exhibitions and wide materials science and engineering of innovative, improved, and elegant research in macroscopic and/or mesoscopic computational materials science and engineering, containing the most advanced mathematical modeling methods and numerical methodology developments. For the sake of investigation of phenomena in materials science modeling and engineering at the macroscopic and mesoscopic scales, several powerful numerical tools, including first principle calculations, quantum molecular dynamics, molecular dynamics and molecular mechanics simulations, Monte Carlo method, finite element method, finite difference method, finite volume method, spectral element method, boundary element method, and computational fluid dynamics, are employed. Meanwhile, these tools are also applied on the research of materials (fluids, metals, polymers, rocks, ceramics, composites, biomaterials, nanomaterials, etc.), their structures (functional solids, soft matter, multiphase materials, tribology, coatings, etc.), and their characteristics (thermal, electronic, energetic, physical, structural, chemical, magnetic, or optical properties or a complicated combination of any of these properties). The analytical and numerical analyses and results of functional elements of these materials constitute the main and outstanding highlights of this special issue; moreover, important computational studies of others aspects also are brilliant and impressive, such as imperfections in materials and their resulting limitations, novel processes for advanced materials synthesis, engineering of material properties, environmental consideration in material performance, and solid materials on sintering/melting process during three-dimensional printing. It enables interdisciplinary collaboration between science and engineering technologists in the academic and industrial fields.

Advanced Materials and Processes for Solar Energy Conversion

In the recent years, our research has been focused on the design and synthesis of advanced materials and the development of novel processes for energy conversion and storage. In this talk, I will summarize our strategies for synthesis of advanced materials, present their application for dye-sensitized solar cells (DSSCs), and discuss new processes for photocatalytic splitting of H2O to H2.

Facile approach to surface functionalized MoS2nanosheets

Two-dimensional layered MoS2 nanosheets exhibit a wide range of attractive properties and hold great promise in myriad fields. However, the poor performance of surface functionality greatly limits their applications. In this paper, we report on a facile approach to direct synthesis of organic functional group decorated MoS2 (OFGD-MoS2) nanosheets based on the simultaneous exfoliation of bulk MoS2 crystals and chemical conjugation of thiol ligands. The morphology and structure of OFGD-MoS2 nanosheets are systematically characterized using microscopy (TEM, SEM, AFM), thermal gravimetric analysis (TGA), and spectroscopy (Raman, FTIR, XPS) measurements. The content of attached functional groups can be controlled simply by changing the experimental conditions. Furthermore, the introduced functional groups show excellent structural stability and high chemical reactivity, making them promising for further modification as confirmed by the in situ growth of inorganic nanoparticles and polymers. In addition, surface functionalized WS2 nanosheets can also be synthesized by this approach. This investigation paves the way for the synthesis and applications of advanced MoS2-based materials.

Functional polymer sheet patterning using microfluidics.

Poly(dimethylsiloxane) (PDMS)-based microfluidics provide a novel approach to advanced material synthesis. While PDMS has been successfully used in a wide range of industrial applications, due to the weak mechanical property channels generally possess low aspect ratios (AR) and thus produce microparticles with similarly low ARs. By increasing the channel width to nearly 1 cm, AR to 267, and implementing flow lithography, we were able to establish the slit-channel lithography. Not only does this allow us to synthesize sheet materials bearing multiscale features and tunable chemical anisotropy but it also allows us to fabricate functional layered sheet structures in a one-step, high-throughput fashion. We showcased the technique's potential role in various applications, such as the synthesis of planar material with micro- and nanoscale features, surface morphologies, construction of tubular and 3D layered hydrogel tissue scaffolds, and one-step formation of radio frequency identification (RFID) tags. The method introduced offers a novel route to functional sheet material synthesis and sheet system fabrication.

Metal ion biosorption on chitosan for the synthesis of advanced materials

Chitosan is an aminopolysaccharide that binds metal ions through different mechanisms such as ion exchange, chelation or formation of ternary complex. The sorption performance depends on the characteristics of the solution (pH, presence of ligands, metal speciation) and the properties of the biopolymer (crystallinity, degree of deacetylation, molecular weight). Sorption performance is also controlled by the accessibility and availability of reactive groups (diffusion properties). These interactions chitosan/metal ions can be used for environmental applications (recovery of toxic or valuable metals) but also for the synthesis of new materials. Hybrid materials (chitosan/metal ion composites) can thus be used for manufacturing new sorbents with improved functionalities, supported catalysts, antimicrobial supports and sensors. The physical versatility of the biopolymer is an important criterion for designing these new materials: The conditioning of the material under the form of hydrogel beads, membranes, fibers and hollow fibers, foams and sponges enhances sorption performance and allows developing new applications.

Dielectric Behaviour of BaTiO<sub>3</sub>-SrTiO<sub>3</sub> Solid Solutions Fabricated by High-Energy Ball Milling

This paper considers the mechanochemical synthesis of advanced electroceramic material with a perovskite structure as well as this method as an effective way for modifying the properties of BaTiO3 by substitution of foreign ions. Dielectric properties mainly para-ferroelectric phase transitions in Ba1-xSrxTiO3 solid solutions (0.0 x 0.6) are presented.

Water-soluble inorganic salt with ultrahigh specific capacitance: Ce(NO3)3 can be designed as excellent pseudocapacitor electrode

The improvement of the performance of pseudocapacitors has previously been limited to the synthesis of electrode materials with different structures and sizes. The water-soluble inorganic salts have not been explored their pseudocapacitance in aqueous electrolyte. Here, for the first time, we demonstrated that the ultrahigh specific capacitance of 2060 F/g can be obtained by the direct use of commercial Ce(NO3)3 as electrode materials in KOH electrolyte without any additional processing. As main capacitive charge-storage ions, Ce3+/Ce4+, which undergo chemical reactions and electrochemical reactions, can deliver high practical specific capacitance that is close to its theoretical value. The results challenge the view that the synthesis of advanced electrode materials with specific structures is the important step to increase the specific capacitance of inorganic pseudocapacitors.

Controlled mechanochemical synthesis and properties of a selected perovskite-type electroceramics

This paper presents mechanochemical synthesis as an alternative to the traditional high-temperature synthesis of advanced electrotechnical ceramic materials with a perovskite-type structure. The reaction conditions for high-energy ball milling, e.g. reaction environment, energy of milling and additives to BaTiO3 such as metallic iron or zirconia from the exfoliation of the milling vessel and grinding media are discussed.