Graphene-ceramic composites are focusing much attention because of their very attractive electrical, thermal, mechanical and tribological properties. Processing routes involve the preparation of graphene/ceramic powders followed by a consolidation step performed by a variety of techniques including spark plasma sintering (SPS). Usual methods involve pre-existing graphene agglomerates prepared from graphite but one of the main challenges is to ensure the homogeneous dispersion of graphene in the powder without introducing undesirable structural defects and inducing contamination. We will discuss an alternative route where composite powders are prepared, without any mixing step, by the chemical vapor deposition (CH4/Ar atmosphere) of carbon in the form of 2-8 layers few-layered-graphene (FLG) covering the ceramic powder grains. Results on the electrical, thermal and mechanical properties of the dense samples prepared by SPS will be discussed. The proposed mechanical reinforcement and toughening mechanisms, such as graphene-pullout, crack-bridging, crack-deﬂection and crack-branching will be presented. The graphene-induced grain-size refinement of the matrix is to be taken into account when discussing the properties. When appropriate, a parallel with carbon nanotube-ceramic composites will be made
Pr. Christophe Laurent is a Full Professor of Materials Chemistry at Université Toulouse 3 Paul-Sabatier, currently Director of CIRIMAT, the Interuniversity Center for Materials Research and Engineering and former head (1998-2015) of its Nanocomposites and Carbon Nanotubes team. Currently Pr. Laurent’ researches focus on the synthesis of carbon nanotubes and graphene (notably the selectivity on the number of walls/layers), ceramic- and metal-matrix nanocomposites and spark plasma sintering. He has published more than 115 papers in peer-reviewed journals.
The application of nanotechnology to medicine (nanomedicine) has become one of the most promising routes for the targeted diagnosis and treatment of diseases. The small size of nanomaterials, large surface area and high reactivity impart unique physicochemical properties to these materials, in such a way that several therapeutics based on nanomaterials (liposomes, nanoparticles, polymers) have been approved for clinical use in the past few years. However, there are still several limitations that need to be overcome to obtain novel and efficient nanocarriers. In this talk we will present recent advances on the development of nanomaterials for biomedical imaging and cancer therapy.
Gerard Tobias obtained the degree in Chemistry (with Honours) from the Autonomous University of Barcelona (2000), Master in Materials Science and Ph.D. with European mention (UAB, ICMAB, 2004). He was a research visitor at Ames Laboratory (USA) and EMAT (Belgium). Between 2004-2009 he was at Oxford University (UK). Since 2009 he leads research on "Nanoengineering of Carbon and Inorganic Materials" at the Materials Science Institute of Barcelona (ICMAB-CSIC). Dr. Tobias has coordinated the FP7 European network RADDEL and has been recently granted an ERC Consolidator Grant (NEST, 725743).
Will be updated soon
Dr. Niloufar RaeisHosseini (Nellie), is a research associate in the Department of Electrical and Electronic Engineering (EEE), Imperial College London, where she conducts her research in a multi-disciplinary team of “Circuit and Systems”. She is an awardee of “Newton International Fellowship” offered by the “Royal Society”. She has fulfilled her first postdoctoral fellowship by awarding a professional research grant from the National Research Foundation (NRF) of South Korean government by joining in “Nanoscale Photonics & Integrated Manufacturing” group at “Pohang University of Science and Technology” (POSTECH), soon after receiving her Ph.D. in “Nanoelectronic Materials and Devices” from the same university. POSTECH as a world-leading research-based university was a place where she gained more than seven years of successful experiences in thin film semiconductor processing, subwavelength nanofabrication, and development of nanoelectronic focusing on Nonvolatile Memories (NVMs), and Neuromorphic Devices. In addition to obtaining practical skills in the fabrication of nanoelectronics, optoelectronics, and nanophotonic devices under a cleanroom environment, she fabricated chalcogenide-based metadevices and realized the origin of switching phenomena using conductive atomic force microscopy (c-AFM) in atomic scale
Both high thermal conductivities and low thermal expansion coefficients (CTEs) are required for heat-sink materials as they promote rapid heat dissipation and reduce thermo-mechanical strains upon thermal cycling. Currently, Cu or Al heat sinks are being used. However, they are not suitable due to the large CTE mismatch with the ceramic and silicon parts in the components. To overcome this issue, we proposed to replace the Cu and Al materials of heat sinks by metal-matrix composites (MMCs), more particularly Al- and Ag-matrix composites reinforced with nano-carbons. The properties of MMCs are often compromised by the absence of effective interfaces, especially in non-reactive systems such as Ag/C and Cu/C. However, for a thermally efficient assembly, the interfaces are needed to allow effective transfer of thermo-mechanical loads between the materials, which is only possible in the presence of chemical bonding. With their extraordinary mechanical, thermal, and electrical properties, carbon nanotubes (CNTs) and graphene are ideal candidates as reinforcements in metal composites. However, nanocarbons are not easy to fabricate. Several challenges, such as the dispersion of the nanocarbons inside the matrix, need to be addressed. To enhance the material properties, a step-by-step procedure has been developed for the fabrication of Cu/CNTs and Ag/graphene composite materials. In order to create strong chemical bonding between the metals and nanocarbons, metallic nanodots are deposited through a new and innovative technique. Mixing, densification processes and conditions are then optimized. Physical and mechanical properties are presented for both Cu/NTC and Ag/graphene composite materials and correlated with the interfacial metal-nanocarbon properties
Dr. Jean-François SILVAIN is a Senior Researcher in the “Institut de Chimie de la Matière Condensée de Bordeaux” (ICMCB-CNRS) and an Adjunct Professor of Engineering at the University of Nebraska – Lincoln (USA). He received his bachelor’s degree from Poitiers University (France) in 1980, and PhD degree from Poitiers University (France) in 1984 both in Material Science. From 1987 to 2002, he was a CNRS Research Fellow at the University of Nancy (France). He joined the “Institut de Chimie de la Matière Condensée de Bordeaux” (ICMCB-CNRS) in 1992. He has over 20 years of experience in composite materials processing and characterization at micro/nanoscales. Dr. SILVAIN’s main field of interest is the processing and the characterization of ceramic and inorganic multi materials ranging from metal and ceramic matrix composite (CMC and MMC) to functionally graded materials (FGM) with the aim to develop materials with adaptive physical (thermal, electrical) and/or mechanical properties. Dr. SILVAIN is currently working on new processes, for metal powders, such as hot extrusion process, equal-channel angular pressing, microwave sintering (with and without pressure), and spark plasma sintering and on laser-mater interaction and additive manufacturing with the University of Nebraska Lincoln (USA). Dr. SILVAIN has authored or co-authored over 160 journal papers and 150 conference papers. He has served as chair of international conferences including the Powder Metallurgy Conference in 2012
Graphene-based nanomaterials (GNMs) are emerging as materials of interest in biomedical applications. In particular, the decoration and functionalization of such nanomaterials with a variety of nanoparticles may provide powerful signal enhancement in several tissue imaging techniques. Graphene oxide based GNMs (GO-GNMs) possess notable geometrical variants, such as flat sheets, tubes, scrolls and spheres, and form stable and easily-processable aqueous solutions. Furthermore, the presence of oxygen containing functional surface groups in GO-GNMs provide potential locations for attachment of various surface chemistry modifiers such as drugs, disease targeting groups as well as decoration with metal nanoparticles, making them viable theranostics platforms. In order to generate 3D graphene structures, we synthesized nanoscale crumpled graphene oxide roses (GO roses) by using colloidal graphene oxide (GO) sheets as precursors in a process involving a oil-in-water emulsification coupled with a rapid evaporation approach. This process produced rose-like, spherical, reduced nanostructures of colloidal graphene oxide, with corrugated surfaces. In addition, we decorated the GO precursors with various metallic nanoparticles such as gold or iron oxide in order to impart to them novel chemical and physical properties. We studied the possible applications of these novel nanostructures as potential theranostics platforms for cancer remediation as MRI contrast agents, tissue delineation indicators and drug delivery agents.
Dr. Tannenbaum is a professor in the Department of Materials Science and Chemical Engineering and a member of the Stony Brook Cancer Center at Stony Brook University in New York. To date she has published over 200 peer-reviewed articles, reviews and conference proceedings. She is the recipient of numerous awards such as the best paper award in the 1st International Conference on Applied Physics (2003), the Sigma Xi best thesis advisor award (2004), the MRS Fall 2006 Meeting outstanding paper award (2007) and the 1st prize in the SAIC best paper competition (2007 and 2010). She is a member of the Advisory Board of several professional journals and a member of several national and international professional societies. Dr. Tannenbaum’s areas of interest are soft condensed matter and complex fluids, graphene-based nanostructures, bio-based functional nanomaterials, and bio-nanostructures tissue imaging and targeted drug delivery.
Nowadays, nanostructured graphene is widely used for the creation of a wide spectrum of heterostructures for different applications. In the report, a nanostructuring of graphene and fluorinated graphene (FG) by high-energy ions, a printed humidity sensor from composite graphene suspension with PEDOT: PSS polymer for flexible electronics and Bi2Se3 /graphene heterostructures will be discussed. Irradiation of materials gives the unique possibility of local modification due to huge ion energy losses on excitation of the material electronic subsystem. It is found that irradiation (Xe ions, 30-170 MeV) leads to the formation of nano-sized pores (20 - 60 nm for graphene and 1 - 3 nm for FG). With increasing in ion energy, a profound reduction in the concentration of structural defects, relatively high carrier mobility (0.7 – 0.9 from that of the pristine graphene) were found in the nanostructured films due to the formation of interlayer covalent bonds. The humidity sensors from graphene-based composite demonstrate not only high sensitivity but also good stability of sensor operation under tensile bending. Bi2Se3 based heterostructures were created using the Bi2Se3 films chemically deposited on the CVD grown graphene or 2D printed graphene layers. For the heterostructures with Bi2Se3 film thickness of 12-50 nm, two types of conductive channels with n- and p-type conductivities, low resistivity ~200-300 Ohm/sq and the high room temperature carrier mobility up to 1000~3400 cm2/Vs were found. All graphene-based nano- and heterostructures discussed in the report have properties perspective for applications. This study was supported by the RFBR grant No. 18-29-12094 and RSF grant No. 19-72-10046
Prof. Dr Irina V. Antonova graduated from the Novosibirsk State Technical University (Department of Physics and Engineering) in 1979. Since 1981 she has been working at the Institute of Semiconductor Physics, Siberian Branch of the Russian Academy of Science. Presently, I.V. Antonova occupies a leading researcher position at the Laboratory of Three-Dimensional Nanostructures, ISP SB RAS. I.V. Antonova received her Ph. D. in semiconductor physics in 1990 for the investigation of inhomogeneous distributions of defects and impurities in silicon. In 2009, I.V. Antonova successfully defended her doctoral dissertation. Her activity was connected with transport and recharging phenomena in nanocomposite layers (Si, Ge nanocrystals in dielectric matrix), and localized states in heterostructures and at interfaces (silicon-on-insulator, SiGe quantum wells and quantum dots), high-pressure-related effects, surface passivation phenomena. Nowadays I.V. Antonova heads a group of researchers dedicated to investigation of graphene and its derivatives. The scope of current research and professional activities of Prof. Dr I.V. Antonova include chemical functionalization of graphene, fabrication of graphene / fluorographene heterostructures and arrays of graphene quantum dots embedded in a fluorographene matrix, 2D printed technologies with graphene based materials, study of transport and recharging phenomena in nanocomposite layers and localized states in heterostructures,. Presently, Prof. Dr Irina V. Antonova has above 280 papers. Sum of the times cited is above 1000, h-index is equal to 14.
By the ‘Ising model, it is possible to calculate and estimate the average crystal lattice energy. The Ising model is based on spins, spin flipping and the random motion trajectory of electrons and particles in crystal lattices. It can be treated based on the Metropolis Hasting Monte Carlo algorithm and other algorithms existing, sampling such as the Umbrella sampling, or modified. The present study is a preliminary investigation to obtain the average crystal lattice in 2D configuration and determining other physical parameters such as magnetization associated with ferromagnetic properties and prospect of investigating phase transitions.
Adewole O has vast & strong expertise in numerical and computational methods, models, he also has strong and intense passion for material science, biochemical engineering, systems biology and imaging. He has wide and broad research experiences covering computational and numerical methods, models, stochastics and economics, Literature Arts, material sciences and quantum mechanics. He is currently the founder, manager and overseer of “Campagna Global Literary Edifice”, which was fully incorporated in Lagos in March, 2017. Other recent research areas include a task to unravel more frontiers in the field of ‘bio-ethanol, fermentation & chemical processing’ and develop numerical based results in this filed in the nearer future. More results would be made available in this field in upcoming events and the nearest future
This presentation on graphene-based nanostructured materials will show following examples how fundamental studies are promising to create innovative technologies for future human society. Dynamic adsorption of mixed 18O2 and 16O2 around 112 K on nanoporous materials gives high adsorption selectivity of > 1.5 , being more than 100 times larger than the current separation technology. The structure of ionic liquid, EMI-TFSI , confined in 0.7 nm slit-shaped pores of carbide-derived carbon was studied with HRMC simulation-aided X-ray scattering. We evidenced the accumulation of EMI cations and TFSI anions in the pores due to the image charge effect . This understanding provides better supercarpacitors . Nanoscale graphene units from graphene oxide enable to produce highly porous carbons . The nanoporous graphene consists of distorted nanoscale graphenes having highly elastic nature[6,7] and their porosity can be tuned by charge-transfer interaction. The excellent separation rate of nanowindows in the graphene for N2, O2, and Ar is evidenced. The nanowindows in graphene can be applicable to separation of alkali ions .
Dr. Katsumi Kaneko studied chemistry at Yokohama National University in Japan and molecular science at master program of University of Tokyo. Dr of Science was awarded by Univ. of Tokyo in 1978. He had been professor of physical chemistry, Chiba University until March in 2010. He moved to Shinshu University in 2010 as distinguished professor. He published more than 500 papers on international journals. Chemical Society of Japan and American Carbon Society awarded him in 1999 and in 2007(Charles Petinos Award), respectively. He is fellow of Royal Society of Chemistry, International Adsorption Society, and Chemical Society of Japan.
Multifunctional composite nanostructures with various ferroelectric, piezoelectric and pyroelectric properties hold much promise for many modern applications. The special interest is focused on the graphene/graphene oxide-based (G/GO) and two-dimensional graphene-like structures (dichalcogenides), in combination with polymer ferroelectrics and another nanostructures. Computer modeling is very beneficial, promising and fast-developed a way of the researching these systems now. Advantages in these studies of composite nanomaterials based on the G/GO with following components are presented and analysed: 1) with polyvinylidene fluoride (PVDF) and (P(VDF-TrFE)) ferroelectric polymers (piezo- and pyro-electric properties); 2) with gas-hydrates, forming complex layered GO-methane-hydrates nanostructures, which can serve as molecular storage systems and separation mechanisms for gas-hydrate components; 3) with hydroxyapatite (HAP) nanocrystals, forming chemically modified GO/HAP composite, which change the band gap and could be tuned for photodegradation under visible light, and can serve for heavy metal removal and antibacterial activity; 4) G-like two-dimensional transition metal dichalcogenide MoS2 monolayers and its composition with polymer ferroelectrics layers (PVDF/P(VDF-TrFE)), creating the composite heterostructure with controlled polarization switching and induce the optical band gap changes (for applications in the fields of optics and electronics); 5) G-base nanostructures creating a variety of nanomaterials, including hydrogenated porous graphene, boron and nitrogen impurities in porous graphene, which is used in many fields, including as a membrane for H2 purification, etc. The computer simulation of these G/GO-based and G-like nanostrcutures were studied using various methods (molecular mechanics, quantum mechanics, Density Functional Theory, semi-empirical PM3 and molecular dynamics runs) and various software (HyperChem, VASP, etc.). Acknowledgement Authors are thankful to the Russian Foundation for Basic Researches grants # 19-01-00519.
Vladimir Sergeevich BYSTROV – PhD, Dr. Habil. Phys. (University of Latvia, Riga), Dr.Sci. Phys.&Math. (Russian Academy of Sciences) since 1993 – has expertise in various fields of the Computational Molecular Modeling and Material Sciences: ferroelectrics polymer PVDF/PVDF-TrFE thin films, graphene/oxide graphene and composite nanomaterials; amino-acids nanocrystals, peptides nanotubes, hydroxyapatite, etc. Computational studies of nanostructures were made using various methods (ab initio, DFT, semi-empirical methods, molecular mechanics), molecular dynamics on the base of HyperChem, AIMPRO, VASP, etc. He is Head of Group for Computer Modeling of Nanostructures and Biosystems of IMPB-KIAM RAS.
Graphene, a 2-dimensional semimetallic monolayer form of sp2-hybridized carbon, has attracted considerable research interest owing to its unique superior physicochemical properties and great application potential. It owns numerous features such as extremely high carrier mobility, high surface area-to-volume ratio, fast electron transfer rate, high thermal conductivity, and large tensile strength. Because of these excellent properties, graphene is considered as a promising candidate for many applications. Theoretical chemistry plays a vital role in understanding the physicochemical properties of graphene and helps to utilize in such applications. This lecture will provide basic theoretical insights and summarize the results of our group's recent use of density functional theory calculations in graphene materials. These include i) development of graphene-based hydrogen storage materials, ii) graphene for high-rate anodes in rechargeable lithium-ion batteries, iii) functionalization of graphene for a counter electrode in dye-sensitized solar cells, and iv) graphene modeling for gas sensors. Information about their structural, electronic and catalytic properties for those various applications will be discussed. I will mainly talk about the functionalities of heteroatom doping in graphene catalytic activity and paying special attention to electroactivity and reactivity by means of applying the external electric field.
Jyh-Chiang Jiang graduated from National Taiwan University in 1986 with a B.S. in Chemistry and received his PhD in Chemistry in 1994 from the National Taiwan University. After working as a postdoctoral fellow at IAMS, Dr. Jiang joined the faculty of National Taiwan University of Science and Technology (NTUST) in 2001 He focuses on the theoretical and computational chemistry study of the heterogeneous catalysis, optoelectronic materials and Li ion batteries. He has worked extensively in the development of combined electronic structure and kinetics methods for simulating processes that involve the reaction mechanisms of H2 production, Hydrogen storage, NH3 oxidation on metal oxide surfaces. Dr. Jiang is also involved in High throughput screening of many new materials for Li ion batteries based on quantum mechanics calculation. In addition, he has been active for many years in design of the optoelectronic materials for DSSCs using quantum mechanics simulation. He has more than 170 papers in peer-reviewed journals. His research has also resulted in 4 patents
Graphene quantum dots (GQDs), fragments limited in size of a single-layer two-dimensional graphene, are considered as the next generation of carbon-based nanomaterials with enormous potential in biomedical field. Due to their outstanding physical, chemical and biological properties, these nanomaterials have shown promising applications in cancer therapy.1 When compared with other carbon-based nanomaterials, GQDs exhibit biologically interesting properties, such as low toxicity, chemical inertness, water solubility and the ability to be internalized inside cells by endocitosis which make them ideal nano-carriers for drug delivery.2 The quantum confinement, which confers fluorescence to these nanostructures, allows the simultane-ous detection and treatment of cancer cells, making them suitable platforms for theranostic purposes.3 The surface/volume ratio and versatile surface functionalization allows their multimodal covalent and non-covalent conjugation with drugs, targeting ligands, and polymers, in order to improve their pharmacological profile.4,5 GQD, synthesized by acidic oxidation and exfoliation of multi-walled carbon nano-tubes (MWCNT) have been conjugated with anticancer agents and with targeting ligands that could specifically recognize specific receptors on the cells surface and induce receptor-mediated endocytosis in order to minimize the systemic toxicity and undesir-able side effects typically associated with conventional therapy (Fig. 1).The reported results lead to targeted therapies forcancer treatment, opening new possibilities in the use of anticancer drugs poorly soluble in water andendowed with systemic toxicity
An ounce of prevention is worth a pound of cure.” ― Benjamin Franklin Corrosion is a significant issue nationally/internationally, resulting in high maintenance and repair costs. As a result, it is imperative to develop improved, coating materials to control corrosion. Several organic coatings are used to protect metals against corrosion; however, these coatings do not provide effective barrier properties against water, moisture, or chloride ions and are very expensive. Hence, there is a need to develop new coatings materials to meet this challenge. Current projections indicate that total losses incurred due to corrosion is ~1 trillion dollars in the U.S. alone. The crux of our multi-functional coating is in deriving the benefits of various fillers and combining them synergistically to produce a robust formulation. Multi- functionality is achieved by a multi component approach. A two-pronged strategy to fight corrosion is adapted to develop a multi-component coating that will provide the coated surface corrosion resistance through: 1)Active protection by using graphene as a conductive filler. 2)Passive protection by introducing clay to reduce water or moisture permeability. A systematic comparative study of samples containing various filler types in epoxy resin was carried for corrosion resistance. Efficacy of graphene as a filler, graphene clay combination was evaluated and compared against commercially used Zinc filler. Samples were investigated for corrosion current, corrosion grade and accelerated corrosion test using salt fog testing as per ASTM B117 showed that Graphene is highly effective in corrosion resistance in polymeric coating
One of the greatest challenges faced in the graphene commercialization is the production of high-quality pure material in bulk quantities at low price and in a reproducible manner. A recent research report about the quality of graphene material available on the market (encompassing 60 different suppliers of graphene) published in Advanced Materials 2018 (doi: 10.1002/adma.201803784) has found that most graphene production companies generate a material that is comprised of only 2-10% of a graphene content. The reason for such low percentages is related with a set of serious drawbacks of conventional methods, such as the use of expensive catalysts, high-temperatures processes, harsh chemistry, lengthy complex procedures. The research team of Plasma Engineering Laboratory (PEL) of Institute of Plasmas e Fusão Nuclear, developed and implemented a highly competitive plasma-based alternative. To this end, microwave-driven plasmas were successfully applied for the first time in the selective, single-step, synthesis-by-design, of high-quality graphene/N-graphene (nitrogen-doped graphene) free-standing sheets and graphene/metal oxides nanocomposites at high-yield and at atmospheric pressure conditions. The plasma ability to control the amount and localization of energy and matter delivered from the plasma bulk to the developing nano-structures is the key that researchers at PEL apply to implement synthesis-by-design, of graphene and derivatives
Carbon nanotubes are very attractive like a reinforcing component into composite materials. Nanotubes are of interest due to their outstanding properties compared with those of commercialized high-performance fibers. For use in the form of fabrics that can save and retranslate such properties, individual CNT should be held together in fibers and bind between each other. There are several ways for that, for instance: direct spinning, during CNT-synthesis by aerosol-way, CNT-forest spinning, which draws and twists CNTs and some post-treatment methods such as surfactant-based coagulation spinning, which injects a polymeric binder between CNTs to form fibers and etc. It is big challenge those CNT fibers to express the outstanding properties of individual CNTs like they are. To solve this challenge post-treatment processes are under development for improving the production process of CNT fibers or enhancing their properties. We report research of fabricating CNT filaments obtained in situ and series some post-treatment processes for property enhancement. Using of cyanoacrylate adhesive and chlorosulfonic acid leads to interesting results. Ultimate tensile strength increased by more than 10 times. The elastic characteristics of the threads have also improved. Thus, our results upgrade the way to the development of carbon-based nanomaterials, which can also provide new applications for CNT
Presently, the resistive memory is recognized as a promising alternative to the existing types of nonvolatile and, first of all, flash memory. Expectedly, the resistive devices will offer much more quick-operating memory, it will allow reaching a much denser data storage capacity, and it will be cheap and simple in fabrication. The advantage of resistive memory based on fluorinated graphene films are the material stability and ability to create films on solid and flexible substrates at room temperature. In the present study, we examined the properties of composite films consisting of fluorinated graphene with added VOÑ… (predominantly, V2O5) nanoparticles and two-layered films based on fluorinated graphene with polyvinyl alcohol. We improve the functionality of the structures by varying the thickness, area, and substrate. Local modification of the material using high-energy ions is the unique approach to nanostructuring and modification of memristors operation. In such two-layered and composite films incorporated in printed crossbar structures, a stable resistive switching effect with ON/OFF current ratio 105 ï¿½ 109, about 30 ns time of switching and up to 1.3x103 switching cycles without any changes in ON/OFF current ratio. The key parameters of the films are the content of the composite material and the film thickness. In addition to the huge and stable switching effect, an advantageous feature of the obtained composite is the possibility to use 2D printed technologies and flexibility created structures. This work is supported by RSF 19-72-10046.
3-dimensional (3D) graphene network with large surface area could be promising material as a platform for electrochemical and bio applications. This kind of carbon nanostructure is called as carbon nanowalls (CNWs), carbon nanoflakes, carbon nanosheets, graphene nanosheets, and graphene nanowalls. CNWs and similar carbon nanostructure are self-supported network of few-layer graphenes standing almost vertically on the substrate to form 3D structure. CNWs can be synthesized by plasma-enhanced chemical vapor deposition (PECVD) on heated substrates (600-800 ˚C) employing methane and hydrogen mixtures. The height of CNWs increases almost linearly with the growth period, while the thickness of each sheet and interspaces between adjacent sheets are almost constant. The maze-like architecture of CNWs with large-surface-area graphene planes would be useful as electrodes for energy storage devices and scaffold for cell culturing. Especially, combined with surface functionalization including surface termination and decoration with nanoparticles and biomolecules, CNWs can be suitable as platform in electrochemical and biosensing applications. We have carried out CNW growth using several PECVD techniques. Moreover, graphene surface was decorated with Pt nanoparticles by the reduction of chloroplatinic acid. We also report the performances of hydrogen peroxide sensor and fuel cell, where CNW electrode was used. Electrochemical experiments demonstrate that CNWs offer great promise for providing a new class of nanostructured electrodes for electrochemical sensing, biosensing and energy conversion applications.
Different authors have demonstrated that incorporating reduced graphene oxide (rGO) to zinc sulfide (ZnS) particles increases the degradation rate of organic pollutants in aqueous media by photocatalytic processes. However, the used methods for chemical reduction of graphene oxide (GO) and synthesis of ZnS-rGO composites involves the use of environment hazardous chemical reagents and/or complicated synthesis methodologies that require high energy demands. Therefore, in this work we report the synthesis of rGO through a green chemistry methodology and its incorporation to ZnS particles in order to enhance photocatalytic activity. In this method, GO, obtained via electrochemical exfoliation of graphite, was reduced with aqueous leaf extract of Azadirachta Indica (Neem). ZnS-rGO composites were made precipitating the ZnS precursors inside rGO aqueous dispersions. ZnS-rGO composites were characterized by XRD, Uv-Vis Spectroscopy and BET method. Morphological characterization of the composites was performed using SEM. Photocatalytic activity studies were performed irradiating Xenon light to the ZnS-rGO composites in Rhodamine B (RhB) aqueous solutions. A decrease of organic pollutant’s half-life from 270 up to 147min compared to pristine ZnS particles was observed.
Thermal plasma (TP) reactors are used for the generation of particles and nanoparticles (NPs) having specific compositions or phases using precursors that are either in the gas phase, in liquid solutions or even in the solid phase. The extreme conditions in a TP environment essentially vaporize and dissociate all species, providing atomic building blocks in their neutral, excited or ionized state. More difficult has been the controll of very specific structures such as the 1-D structure of carbon nanotubes, or 2-D structures of graphene using homogeneous nucleation of a critical cluster and growth of these building blocks in the gas/plasma phase. This presentation will first discuss the motivations behing the generation of a bottom-up approach for generating graphene powders. The application in mind relates to PEM-Fuel Cell catalysts, setting specific requirements on both the structure and the functionalities to be imbedded on the graphene material. These motivated the thermal plasma route enabling exceptionally high levels of crystallinity and purity. It also required “tunability” for in situ chemical functionalization of the graphene material made essentially from pure carbon up to a specific level of required functionalities. To achieve this, a strong control of the flow, energy, chemistry and particles nucleation fields is essential in the reactor, the homogeneous nucleation and growth occurring within an extreme temperature window between 4500 K and 5000 K. The talk will relate to achieving an understanding of this controlled environment through experiment, reactor design and modeling of the graphene nucleation and growth process. Discussion will also be made on the catalyst generated and tested in a PEM-FC environment as well as out-of-the-reactor graphene powder dispersions (nanofluids) maintaining their stability over periods of years
Surface electromagnetic waves (SEW) have been known for 200 years. Currently, they are widely used in optical and investigated at THz frequencies in the area which form the basis of the current status and future development of nanotechnologies (plasmonics). The history of the research of electromagnetic waves that are different in nature from spatial Maxwell-Hertz electromagnetic waves and emerging on the boundary of two media with different dielectric properties, developed from universal acceptance in the early 20th century the concept of SEW Sommerfeld- Zenneck , until her categorical denial by middle-century, the revival of interest in 60-years and experimental confirmation by the beginning of the 21st century. In Russia, the theory of SEW developed intensively, and experimental proof of the existence of SEW was given: waves of ultrahigh frequencies detected and investigated in the laboratory in the magnetized semiconductors, on salt (w. h. Ocean) water, gas plasma and metals; were observed in vivo. SEW exist at frequencies up to optical. To date, they are best explored in the ultra high frequency range and optics (plasmon- polaritons) .Extended field studies in the field of high, low and Ultralow frequencies holds exciting prospects: (OTH) radar, new channels of global telecommunications, monitoring the surface of oceans, weather management, wireless transfer of energy flows on the surface of Earth and the bottom edge of the ionosphere from continent to continent. SEW have dramatic past, pragmatic present and a great future.
Printed Electronics creates electrically functional devices by printing on variety of substances. Compared to conventional manufacturing of microelectronics, printed electronics is characterized by simpler and more cost-effective fabrication of high and low volume products. Despite its many benefits, to date the performance of printed electronics in terms of the actual function and reliability is less than that of conventional electronics. One of the biggest current challenges facing printed electronics lies in the materials used for printing: currently there are only few substrates available. There are many nanomaterials and nanoparticles but few researchers are formulating these into printable solutions (functional ink). The use of functional materials and nanoparticles in inks has broaden the scope of applications that printed electronics enables. Suppliers formulating novel functional inks and setting up high-volume ink manufacturing facilities will in the near future have an important role in the development and commercialization. Printed Electronics enables applications in almost all industry sectors. According to expert opinion, RFIDs and sensors are so far the most interesting targets but biocompatible electronics, batteries, displays and LEDs are also soon to be seen. Printed electronics creates electrically functional devices by utilizing of traditional printing processes and broad range of substrates. So far, the most common substrates are polymer films, ceramics, glass and silicon. Printing of functional devices on paper is also possible. In contrast to the term’s organic semiconductors, metallic conductors, nanoparticles, nanotubes etc. Compared to conventional microelectronics, printed electronics is characterized by simpler and more cost-efficient fabrication of both high and low volume products. It enables roll-to-roll fabrication and the processes employed to manufacture printed electronics also are more flexible, enabling shorter production runs. Very small series, customized or even unique products are possible through a digital printed process. Another advantage is its processing at low temperatures. The substrate is a solution which is printable and coatable enabling also flexible products. The additive processes might prove to be more environmentally friendly.
Vladimir Mordkovich has completed his PhD from Moscow State University, Russia and then Dr.Sci. from Institute for Materials Science Problems, Ukraine. He spent 11 years in Japan as a senior researcher in governmental and corporate projects and then returned to Russia to become a head of a New Chemical Technologies and Nanomaterials department at Technological Institute for Superhard and Novel Carbon Materials and also a CTO of INFRA Technology Ltd., an international technology company in gas-to-liquid and gas-to-solid technologies. He has published more than 150 papers in reputed journals and authored 52 patents.