Microwave Plasma Synthesis of Materials—From Physics and Chemistry to Nanoparticles: A Materials Scientist’s Viewpoint
18 Aug 2014-Vol. 2, Iss: 3, pp 468-507
TL;DR: In this paper, microwave plasmas are used for the synthesis of inorganic materials and material groups, including bare Fe2O3 nanoparticles, core/shell ceramic/organic shell nanoparticles and Sn-based nanocomposites.
Abstract: In this review, microwave plasma gas-phase synthesis of inorganic materials and material groups is discussed from the application-oriented perspective of a materials scientist: why and how microwave plasmas are applied for the synthesis of materials? First, key players in this research field will be identified, and a brief overview on publication history on this topic is given. The fundamental basics, necessary to understand the processes ongoing in particle synthesis—one of the main applications of microwave plasma processes—and the influence of the relevant experimental parameters on the resulting particles and their properties will be addressed. The benefit of using microwave plasma instead of conventional gas phase processes with respect to chemical reactivity and crystallite nucleation will be reviewed. The criteria, how to choose an appropriate precursor to synthesize a specific material with an intended application is discussed. A tabular overview on all type of materials synthesized in microwave plasmas and other plasma methods will be given, including relevant citations. Finally, property examples of three groups of nanomaterials synthesized with microwave plasma methods, bare Fe2O3 nanoparticles, different core/shell ceramic/organic shell nanoparticles, and Sn-based nanocomposites, will be described exemplarily, comprising perspectives of applications.
TL;DR: This Review critically examines the catalytic mechanisms relevant to each specific application of plasma catalysis, including CO2 conversion, hydrocarbon reforming, synthesis of nanomaterials, ammonia production, and abatement of toxic waste gases.
Abstract: Thermal-catalytic gas processing is integral to many current industrial processes. Ever-increasing demands on conversion and energy efficiencies are a strong driving force for the development of alternative approaches. Similarly, synthesis of several functional materials (such as nanowires and nanotubes) demands special processing conditions. Plasma catalysis provides such an alternative, where the catalytic process is complemented by the use of plasmas that activate the source gas. This combination is often observed to result in a synergy between plasma and catalyst. This Review introduces the current state-of-the-art in plasma catalysis, including numerous examples where plasma catalysis has demonstrated its benefits or shows future potential, including CO2 conversion, hydrocarbon reforming, synthesis of nanomaterials, ammonia production, and abatement of toxic waste gases. The underlying mechanisms governing these applications, as resulting from the interaction between the plasma and the catalyst, rend...
TL;DR: The state-of-art in the manufacture and applications of inorganic nanoparticles made using continuous hydrothermal flow synthesis (CHFS) processes are summarized, ideal requirements of any flow process for nanoceramics production are introduced, different approaches to CHFS are outlined, and the pertinent properties of supercritical water and issues around mixing in flow are introduced.
Abstract: Nanomaterials are at the leading edge of the emerging field of nanotechnology. Their unique and tunable size-dependent properties (in the range 1–100 nm) make these materials indispensable in many modern technological applications. In this Review, we summarize the state-of-art in the manufacture and applications of inorganic nanoparticles made using continuous hydrothermal flow synthesis (CHFS) processes. First, we introduce ideal requirements of any flow process for nanoceramics production, outline different approaches to CHFS, and introduce the pertinent properties of supercritical water and issues around mixing in flow, to generate nanoparticles. This Review then gives comprehensive coverage of the current application space for CHFS-made nanomaterials including optical, healthcare, electronics (including sensors, information, and communication technologies), catalysis, devices (including energy harvesting/conversion/fuels), and energy storage applications. Thereafter, topics of precursor chemistry and ...
TL;DR: In this paper, a review of different plasma functionalization processes of graphene and its oxide counterpart is presented, which aims at the advantages of plasma functionalisation over the conventional doping techniques.
Abstract: Recently, there have been enormous efforts to tailor the properties of graphene. These improved properties extend the prospect of graphene for a broad range of applications. Plasmas find applications in various fields including materials science and have been emerging in the field of nanotechnology. This review focuses on different plasma functionalization processes of graphene and its oxide counterpart. The review aims at the advantages of plasma functionalization over the conventional doping techniques. Selectivity and controllability of the plasma techniques opens up future pathways for large scale, rapid functionalization of graphene for advanced applications. We also emphasize on atmospheric pressure plasma jet as the future prospect of plasma based functionalization processes.
TL;DR: A large amount of the recent literature on graphene production by various techniques is analyzed and a significant potential of scalability for plasma-based technologies is revealed, based on the scaling-related process characteristics.
Abstract: Graphene, a newly discovered and extensively investigated material, has many unique and extraordinary properties which promise major technological advances in fields ranging from electronics to mechanical engineering and food production. Unfortunately, complex techniques and high production costs hinder commonplace applications. Scaling of existing graphene production techniques to the industrial level without compromising its properties is a current challenge. This article focuses on the perspectives and challenges of scalability, equipment, and technological perspectives of the plasma-based techniques which offer many unique possibilities for the synthesis of graphene and graphene-containing products. The plasma-based processes are amenable for scaling and could also be useful to enhance the controllability of the conventional chemical vapour deposition method and some other techniques, and to ensure a good quality of the produced graphene. We examine the unique features of the plasma-enhanced graphene production approaches, including the techniques based on inductively-coupled and arc discharges, in the context of their potential scaling to mass production following the generic scaling approaches applicable to the existing processes and systems. This work analyses a large amount of the recent literature on graphene production by various techniques and summarizes the results in a tabular form to provide a simple and convenient comparison of several available techniques. Our analysis reveals a significant potential of scalability for plasma-based technologies, based on the scaling-related process characteristics. Among other processes, a greater yield of 1 g × h−1 m−2 was reached for the arc discharge technology, whereas the other plasma-based techniques show process yields comparable to the neutral-gas based methods. Selected plasma-based techniques show lower energy consumption than in thermal CVD processes, and the ability to produce graphene flakes of various sizes reaching hundreds of square millimetres, and the thickness varying from a monolayer to 10–20 layers. Additional factors such as electrical voltage and current, not available in thermal CVD processes could potentially lead to better scalability, flexibility and control of the plasma-based processes. Advantages and disadvantages of various systems are also considered.
TL;DR: Microwave discharges (MDs) are widely used as a source of non-equilibrium low pressure plasma for different applications as mentioned in this paper, and a general look at MDs and their application is given in the introduction, together with a description of a typical block-schema of the microwave plasma generator, classification of MD, and attractive features of MD.
Abstract: Microwave discharges (MD) are widely used as a source of non-equilibrium low pressure plasma for different applications. This paper reviews the methods of microwave plasma generation at pressures from 10−2 approximately to 30 kPa with centimeter–millimeter wavelength microwaves on the basis of scientific publications since 1950 up to the present. The review consists of 16 sections. A general look at MDs and their application is given in the introduction, together with a description of a typical block-schema of the microwave plasma generator, classification of MD, and attractive features of MD. Sections 2–12 describe the different methods of microwave plasma generators on the basis of cavity and waveguide discharges, surface and slow wave discharges, discharges with distributed energy input, initiated and surface discharges, discharges in wave beams, discharges with stochastically jumping phases of microwaves, discharges in an external magnetic field and discharges with a combination of microwave field and dc and RF fields. These methods provide the possibility of producing nonequilibriun high density plasma in small and large chambers for many applications. Plasma chemical activity of nonequilibrium microwave plasma is analyzed in section 13. A short consideration of the history and status of the problem is given. The main areas of microwave plasma application are briefly described in section 14. Non-uniformity is the inherent property of the majority of electrical discharges and MDs are no exception. Peculiarities of physical–chemical processes in strongly non-uniform MDs are demonstrated placing high emphasis on the influence of small noble gas additions to the main plasma gas (section 15). The review is illustrated by 80 figures. The list of references contains 350 scientific publications.
01 Jan 1983
TL;DR: This book describes the fundamental aspects of fluorescence, the biochemical applications of this methodology, and the instrumentation used in fluorescence spectroscopy.
Abstract: Fluorescence methods are being used increasingly in biochemical, medical, and chemical research. This is because of the inherent sensitivity of this technique. and the favorable time scale of the phenomenon of fluorescence. 8 Fluorescence emission occurs about 10- sec (10 nsec) after light absorp tion. During this period of time a wide range of molecular processes can occur, and these can effect the spectral characteristics of the fluorescent compound. This combination of sensitivity and a favorable time scale allows fluorescence methods to be generally useful for studies of proteins and membranes and their interactions with other macromolecules. This book describes the fundamental aspects of fluorescence. and the biochemical applications of this methodology. Each chapter starts with the -theoreticalbasis of each phenomenon of fluorescence, followed by examples which illustrate the use of the phenomenon in the study of biochemical problems. The book contains numerous figures. It is felt that such graphical presentations contribute to pleasurable reading and increased understand ing. Separate chapters are devoted to fluorescence polarization, lifetimes, quenching, energy transfer, solvent effects, and excited state reactions. To enhance the usefulness of this work as a textbook, problems are included which illustrate the concepts described in each chapter. Furthermore, a separate chapter is devoted to the instrumentation used in fluorescence spectroscopy. This chapter will be especially valuable for those perform ing or contemplating fluorescence measurements. Such measurements are easily compromised by failure to consider a number of simple principles."
01 Dec 1960
TL;DR: In this paper, the authors present a model for the development of the MICROSTRUCTURE in CERAMICS based on phase transformation, glass formation and glass-Ceramics.
Abstract: INTRODUCTION. Ceramic Processes and Products. CHARACTERISTICS OF CERAMIC SOLIDS. Structure of Crystals. Structure of Glasses. Structural Imperfections. Surfaces, Interfaces, and Grain Boundaries. Atom Mobility. DEVELOPMENT OF MICROSTRUCTURE IN CERAMICS. Ceramic Phase Equilibrium Diagrams. Phase Transformation, Glass Formation and Glass--Ceramics. Reactions with and between Solids. Grain Growth. Sintering and Vitrification. Microstructure of Ceramics. PROPERTIES OF CERAMICS. Thermal Properties. Optical Properties. Plastic Deformation, Viscous Flow and Creep. Elasticity, Anelasticity and Strength. Thermal and Compositional Stresses. Electrical Conductivity. Dielectric Properties. Magnetic Properties.
TL;DR: Some of the recent scientific advances in nanomaterials, and especially in nanostructured materials, for rechargeable lithium-ion batteries are reviewed.
Abstract: Energy storage is more important today than at any time in human history. Future generations of rechargeable lithium batteries are required to power portable electronic devices (cellphones, laptop computers etc.), store electricity from renewable sources, and as a vital component in new hybrid electric vehicles. To achieve the increase in energy and power density essential to meet the future challenges of energy storage, new materials chemistry, and especially new nanomaterials chemistry, is essential. We must find ways of synthesizing new nanomaterials with new properties or combinations of properties, for use as electrodes and electrolytes in lithium batteries. Herein we review some of the recent scientific advances in nanomaterials, and especially in nanostructured materials, for rechargeable lithium-ion batteries.
"Microwave Plasma Synthesis of Mater..." refers methods in this paper
...994 mA h g ) than currently used carbon anodes (372 mA h g )....
TL;DR: Lithium can be inserted reversibly within most carbonaceous materials as mentioned in this paper, but the physical mechanism for this insertion depends on the carbon type and the type of carbon type used.
Abstract: Lithium can be inserted reversibly within most carbonaceous materials. The physical mechanism for this insertion depends on the carbon type. Lithium intercalates in layered carbons such as graphite, and it adsorbs on the surfaces of single carbon layers in nongraphitizable hard carbons. Lithium also appears to reversibly bind near hydrogen atoms in carbonaceous materials containing substantial hydrogen, which are made by heating organic precursors to temperatures near 700°C. Each of these three classes of materials appears suitable for use in advanced lithium batteries.
TL;DR: In this article, an overview on lithium alloys and lithium alloying metals for use as anodes in ambient temperature rechargeable lithium batteries is given, with a brief introduction about advantages and drawbacks of lithium alloy anodes and a chronological review of their development.
Abstract: This article gives an overview on lithium alloys and lithium alloying metals for use as anodes in ambient temperature rechargeable lithium batteries. After a brief introduction about advantages and drawbacks of lithium alloy anodes and a chronological review of their development, principle concepts to overcome the problems with the dimensional stability of the metallic host materials will be presented. Recent work on promising multiphase (composite and/or intermetallic) tin-based lithium alloying materials will be highlighted.
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