Symposium CE
Innovative Synthesis and Processing of Nanostructured, Nanocomposite and Hybrid Functional Materials for Energy and Sustainability

Session CE-1 - Innovative Processing of Nano- and Heterostructures and Films of Functional Materials

CE-1:IL01  Compositional and Nanostructure Engineered Thin Film Materials for Electrochemical Devices Prepared by Chemical Solution Deposition
T. SCHNELLER, Institut für Werkstoffe der Elektrotechnik II, RWTH Aachen University of Technology, Aachen, Germany

Chemical solution deposition (CSD) represents a powerful method for the fabrication of complex oxide thin films due to its high flexibility with regard to composition, materials, and deposition technique at comparably low cost [1]. The prepared oxide ceramic thin films are highly interesting for a number of applications in electronic devices. In particular their use in energy devices such as solid oxide fuel cells (SOFC) and other electrochemical cells is of increasing significance, due to the growing demand for alternative and renewable energy sources as well as a more efficient use of energy. In order to optimize the performance of the thin film devices the control of the phase formation process, microstructure evolution and patterning is of utmost importance.
In this paper firstly a short overview on the basic principles of morphology control for CSD derived complex electronic oxide films is given. This will be complemented by modern approaches for the preparation of nanocomposites using dedicated mixtures of microemulsion derived nanoparticle dispersions and traditional precursor solutions as well as ink jet printing for simultaneous deposition and patterning. Finally the benefit of the gained morphology engineering knowledge will be illustrated using solid electrolyte and cathode films for proton conducting SOFCs, and photoanodes as examples.
[1] T. Schneller, R. Waser, M. Kosec, D. Payne (Eds.) "Chemical Solution Deposition of Functional Oxide Thin Films" (2013) ISBN 978-3-211-99310-1.


CE-1:IL02  Fabrication of High-quality Crystal Layers of Lithium Ion Conductors toward All-Crystal-State Lithium Ion Secondary Batteries
K. TESHIMA^{1, 2}, N. ZETTSU^{1, 2}, H. WAGATA^{1, 2}, S. OISHI¹, ¹Shinshu University, Nagano, Japan; ²CREST, Japan Society and Technological Agency

High quality crystals are indispensable materials in many applications because of the single crystals will provide the potential for exhibiting their near-marginal performances. This is particularly important concept in the material development for solid-state energy-conversion devices, including lithium-ion secondary batteries (LIBs). For instances, active materials and solid-electrolytes with high crystallinity have achieved higher C-rate performance and longer cycle life because lithium ions move smoothly in the crystal lattices. All-solid-state LIBs that employ a solid electrolyte are generally considered to be safer than those use liquid organic electrolytes by removing the issue of flammability. However the charge transfer resistance is strongly affected by interfacial contact condition, it is indispensable to establish design techniques of hierarchically-structured materials integrating from atomic to micro scale spaces for the optimization of phase-interface structures. In this talk, we report our findings on flux growth-based crystal design and engineering toward all-crystal-state LIBs, including direct fabrication of active material layers with high crystallinity on current collectors, interfacially-bonded assemblies of solid electrolytes, and their LIB properties.


CE-1:L03  Chemical Processing and Microstructures of Thin Films for Li Battery Application
Y.H. IKUHARA¹, XIANG GAO¹, C.A.J. FISHER¹, A. KUWABARA ¹, H. MORIWAKE¹, R. HUANG^1,2, Y. IKUHARA^1,3, H. OKI⁴, K. KOHAMA⁴, ¹Nanostructures Research Laboratory, Japan Fine Ceramics Center, Nagoya, Japan; ²Ministry of Education, East China Normal University, Shanghai, China; ³Institute of Engineering Innovation, The University of Tokyo, Tokyo,  Japan; ⁴Toyota Motor Corporation, Susono, Japan

Lithium manganese oxide (LiMn2O4) is a promising cathode material for the batteries because of its low cost, abundant availability, higher safety and environmental compatibility. For future application for all-solid-state batteries, multilayer thin films are needed to be fabricated, and it is required to study the microstructure of cathodic film and interfaces structures of film and substrate, including the crystal orientation, to provide optimal and stable battery performance. This study demonstrates that LiMn2O4 epitaxial thin films can be fabricated on the different single-crystal substrates by chemical solution deposition method (CSD) and the interface structures were investigated to understand its effect on the lithium interecalation-deintercalation behavior. Epitaxial LiMn2O4 thin film on Au/Al2O3 (0001) substrate fabricated using [Li-Mn-O] metalorganic precursor solution was intensively studied by XRD and HREM. Furthermore, STEM observations were performed using a Cs-corrected STEM with a high-angle annular dark-field (HAADF) and annular bright detector and annular bright-field (ABF) detector. Li colums van be observed clearly in the interior of the films.


CE-1:L05  Pseudocapacitive Properties of ZnO/MnOx Core-Shell Nanostructure
CHIN-YI CHEN, HSIANG-CHUN CHEN, Department of Materials Science and Engineering, Feng Chia University, Taichung, Taiwan, ROC

With the increasing demand of electrical energy, electrochemical supercapacitors have been attracted numerous of R&D attentions due to the high power and energy densities and their high cycle stability. In the present experiment, highly oriented ZnO nanorods were first prepared by chemical bath deposition (CBD) on a stainless steel substrate at 70 °C. The manganese oxide was subsequently coated onto the ZnO nanorods to form a ZnO/MnOx core-shell nanostructure by anodic deposition. The CBD ZnO nanorods were vertically well-aligned and uniformly distributed on the substrate. Optimized concentration of the deposition solution was conducted for the MnOx deposition as a function of deposition time. Cyclic voltammetry (CV) curves show that the specific capacitances of ZnO/MnOx core-shell nanostructure were 222, 194, 136 and 112 F/g for the deposition times at 10, 20, 30 and 40 s, respectively. The core-shell nanostructure exhibited an excellent long-term cycling stability with 95% capacitance retention after 1200 CV cycles.


CE-1:IL06  Chemically Engineered Functional Nanostructures for Energy and Health Applications
S. MATHUR, Inorganic and Materials Chemistry, Institute of Inorganic Chemistry, University of Cologne, Cologne, Germany

Chemical nanotechnologies have played, in the past few decades a major role in the convergence of life, physical and engineering sciences leading not only to simple collaboration among the disciplines but to a paradigm shift based on true disciplinary integration. The successful synthesis, modification and assembly of nanobuilding units such as nanocrystals and wires of different materials have demonstrated the importance of chemical influence in materials synthesis, and have generated great expectations for the future. Implications of chemistry as an innovation motor are now visible for knowledge leap forward in various sectors such as materials engineering for energy, health and security.
Inorganic nanostructures inherit promises for substantial improvements in materials engineering mainly due to improved physical and mechanical properties resulting from the reduction of microstructural features by two to three orders of magnitude, when compared to current engineering materials. This talk will present how chemically grown nanoparticles, nanowires and nanocomposites of different metal oxides open up new vistas of material properties, which can be transformed into advanced material technologies. The examples will include microwave-assisted synthesis of superparamagnetic iron oxide nanoparticles for drug delivery applications, and chemically controlled production of heterostructures for sensing and light-harvesting application.


CE-1:IL07  Silicon Nanowires: From Energy Production to (Bio)-Photonics
V. SIVAKOV, Institute of Photonic Technology, Jena, Germany

The future of modern society is tied to the availability of sustainable energy resources. However, among various sources of energy, sunlight is the most abundant and cleanest natural energy resource. Photovoltaics hold a great promise to exploit the sunlight to generate clean energy to accommodate the ever-increasing energy demands. About 90% of solar photovoltaic modules are silicon-based. The grid parity of electricity produced by solar cells is close to 1 USD/Watt assuming a 20-year lifetime of the cells, but the price is currently higher. One obvious way to lower the cost is to reduce the amount of silicon or increase photovoltaic material efficiency. It is presumed that the grid parity of solar cells can be reached by using nanostructured semiconductors or a new solar cell architectures that is most-likely based on nanotechnology. Over the last several years, wet chemically etched silicon nanowires have been favoured by the IPHT “Semiconductor Nanostructures” Department as a promising highly effective optoelectronic material due to a number of unique physical-chemical properties such the ability to tune the optical band gap and the absorption spectrum. Creation of one-dimensional nanostructures has opened up a new area for device applications in electronics, optoelectronics, thermoelectronics, photocatalysis, photovoltaics, sensor, and bio-imaging. For all device concepts based on SiNWs, the crystal structure, geometry (alignment of SiNW with respect to the substrate), interfacial properties between the SiNW and the substrate as well as the Si core and the SiO2 shell of the SiNW (shell can either be native or thermally grown oxide), dopant concentrations and impurity levels are of key importance for functioning of the devices.
Silicon nanowire (SiNW) ensembles with different architectures have been realized using wet chemical etching of bulk silicon wafers with an etching hard mask of silver nanoparticles that are deposited by wet electroless deposition. While recent advances have been impressive, cost, durability, and performance remain as key challenges to silicon nanowire based devices. We showed that silicon nanowires with different morphologies and geometries with unique optical and electrical properties can be successfully and easily produced by top-down technology. SiNWs could penetrate into the living cells via an endocytosis mechanism. Therefore, SiNWs can be used as luminescent labels for living cells. The bio-imaging and therapy using silicon nanostructures will be discussed. We anticipate that the concepts presented here will also be highly relevant to the development of future, more efficient photovoltaic single- or multi-junction devices or to efficient material for solar fuel production.


CE-1:L08  Submerged Liquid Plasma for the Formation of Polymers and Nanostructured Carbon
M. YOSHIMURA, J. SENTHILNATHAN, Promotion Centre for Global Materials Research (PCGMR), Department of Material Science and Engineering, National Cheng Kung University, Tainan, Taiwan

Different forms of carbon prepared from diverse syntyetic routes are currently being used in various fields of research including environmental, electrical, chemical, and biomedical application. In general, carbon based materials like graphene, carbon nanotube, carbon nitride, diamond like carbon etc. are prepared from gaseous precursors such as CVD, PVD and ion-assisted sputtering techniques [1]. We believe that the large scale synthesis of nanostructured carbon should be free from using excess energy for firing, sintering, melting and expensive equipment. We, propose herewith "Submerged Liquid Plasma (SLP)" technique for direct formation of nanostructured carbon material and nitrogen polymers (NPs) at ambient conditions. The SLP process provides number of advantages which include (a) simple reaction set up (b) reaction can be carried out at ambient conditions (c) periodic collection of samples gives clear information about the product (d) simple procedure and less operating cost. In the present study, we utilized SLP technique for the formation of diamond like carbon and direct patterning of carbon films on Si substrates using organic solvent precursors [2]. Furthermore, we utilized SLP technique for the direct synthesis of NPs. Under SLP, organic compounds which have either unsaturated or high energy functional group (e.g. C＝C, C＝N and C≡N) form stable free radical monomer and initiate polymerization reaction.[3] The most significant differences are that the polymers produced by plasma process do not contain regular or repeating units and are enriched with radicalized functional groups. Low temperature or Soft Processing of nanostructured carbon and NPs by SLP process will open up new possibilities for the development of functionalized/hybrid nanostructured carbon materials for various applications.
References:
1) J. Senthilnathan, C. C. Weng, J. D. Liao, M. Yoshimura, Sci. Rep. 3, 2414; DOI:10.1038/srep02414 (2013)
2) Watanabe, T. Wang, H. Yamakawa, Y. Yoshimura, M. Carbon 44, 799−823 (2006)
3) J. Senthilnathan, M.Yoshimura et al., Carbon, to be published


CE-1:IL11  Hybrid Nanomaterials for Electrochemical Devices in Energy Management
POOI SEE LEE, School of Materials Science and Engineering, Nanyang Technological University, Singapore

Functional hybrid nanomaterials are of great interest for the fabrication of complex nanoelectronics, optoelectronics and electrochemical devices. In particular, electrochemical active hybrid nanocomposites are very useful for energy management using electrochemical principles, such as for electrochromics and supercapacitors. In this talk, we elaborate our efforts on the synthesis of unique hybrid nanomaterials for electrochromics such as WO3/RGO and PEDOT/WO3. We will also elaborate hybrid nanomaterial such as MnO2/PANI, NiCo2O4/RGO and MnO2/RGO for supercapacitors applications. The energy densities of these electrochemical devices are enhanced with the shorten ion diffusion length and improved electronic conductivities. Eectrochromics nanocomposites benefitted from the stable and facile ion intercalations for enhanced optical contrast and fast switching speed. These lead to overall efficiency and feasibility in the formation of robust electrochromics devices for energy management.


CE-1:IL12  Template-Free Fabrication of Stripe and Grid Patterns of Colloidal Nanoparticles by Convective Self-Assembly
M.T. MIYAHARA, Y. MINO, S. WATANABE, Dept. Chem. Eng., Kyoto University, Kyoto, Japan

The arrangement of colloidal nanoparticles into ordered structures is a fundamental technique for various applications. In a typical approach, topographically or chemically pre-modified substrates are utilized to assemble particles into a desired configuration, which, however, involves complicated and costly processes.
The convective self-assembly is an attractive process, in which a substrate is immersed in a colloidal suspension, and the particles are carried into the contact line by convective flow of solvent induced by evaporation at the tip of the meniscus.
A highly ordered stripe array forms on a hydrophilic substrate. The key factor for the stripe pattern is the concentration in the suspension. Simply repeating this process with the substrate tilted by 90 degree as the second step, particles will assemble into a grid pattern, which however has never been accomplished without the plasma cleaning in between the two steps: The recovery of complete hydrophilicity is indispensable.
We developed a simple model to predict the periodicity of the resultant colloidal stripes, and fabricated a large-size colloidal grid network pattern of gold or silver nanoparticles to demonstrate the versatility of our method.


CE-1:L13  Nanomaterials in the C-B-N System
R.N. SINGH, School of Materials Science and Engineering College of Engineering, Architecture and Technology, Oklahoma State University, Tulsa, OK, USA

Materials in the C-B-N system have extraordinary properties such as Diamond and cubic-BN. Nanotubes (NTs) belonging to this system have also attracted a significant attention for applications in nanoelectronics, medicine, energy systems, and reinforced-composites. The discovery of carbon nanotubes (CNTs) has generated intense experimental and theoretical interests but their applicability have been limited by their small length and variable/anisotropic properties that are dependent on the number of tube walls, tube diameter and chirality. In contrast, boron nitride nanostructured materials, an III-V compound with similar hexagonal structure to graphite, have more uniform electronic properties with a larger band gap (~5.8eV) than the CNTs. Besides, boron nitride nanotube (BNNT) is a unique tubular material combining ultimate strength, stable dielectric properties and transparency. Our research group has done research work on synthesizing novel nanostructured materials in the C-B-N system. Specifically, our research work on nanostructured diamond and BNNTs will be presented and discussed.


CE-1:L14  Preparation and Growth of ZnO Crystals in Ionic Liquid Flux
H. WAGATA, N. HARATA, N. ZETTSU, S. OISHI, K. TESHIMA, Department of Environmental Science & Technology, Faculty of Engineering, Shinshu University, Nagano, Japan

Zinc oxide (ZnO) has attractive physical/chemical properties such as high electric conductivity, optical absorption and emission, piezoelectricity, and catalytic activity. Simple, cost-effective, and environmentally-friendly methods achieving high-quality ZnO crystals with idiomorphic shape are required for such applications. In this regard, our group has developed a flux method, in which target crystals (=solute) are once dissolved in flux (= solvent; molten metals or molten metal salts), and then, they are re-crystallized by increasing the supersaturation. In this research, we report a facile process for creating ZnO crystals by the flux method with an ionic liquid, deep eutectic solvent (DES), as a solvent. Ionic liquid is a promising solvent for lowering processing temperature of the flux method due to their melting point less than 100 °C. ZnO powder was dissolved in DES to prepare the precursor solution containing 40 mol% of ZnO. The precursor solution was coated on a glass substrate with 100 nm of ZnO seed layer, and then heated to promote the crystal growth from the precursor. The grown crystals were characterized by X-ray diffraction, scanning electron microscopy, and energy dispersive X-ray spectroscopy.


Session CE-2 - Functional Metal Oxide Nano- and Heterostructures

CE-2:IL01  Surface Tuning of Technologically Important Metal Oxides
G. THORNTON, London Centre for Nanotechnology, University College London, London, UK

Modifying the surface properties of functional metal oxides is of importance in a number of technological applications. These include nanoelectronics (single molecule devices, resistive switching) as well as catalysis. Here we will focus on some examples of tuning the properties of TiO2(110), a prototypical metal oxide surface. These include the use of electrons to create oxygen vacancies, reconstruct the surface, and generally disrupt the surface order. Electrons from the tip of scanning tunneling microscope (which is also employed to image the surface) as well as a filament are used as the electron sources. More subtle modifications can be introduced by manipulating atoms using STM-this technique can be used to engineer particular clusters of surface polarons. In one example I will show the use of an electron beam to pattern the surface so as to form iron wires, which have potential in the formation of interconnects for nanocircuits.


CE-2:IL04  Zinc oxide: Morphology and Growth
Z. CRNJAK OREL, National Institute of Chemistry, Ljubljana, Slovenia

The influence of various preparation methods on morphology, growth of ZnO particles with 1D nano- or microdimensional structure was studied and the "junction" in the middle of the bipod was defined as an inversion domain boundary containing a single atomic layer of silicon.
The chemical aspect of the particle growth was proposed in the frame of the partial charge model (PCM). The formation of [Zn(OH)2(OH2)4]0 and [Zn(OH)(HCO3)(OH2)3]0 was predicted. The presence of [Zn(OH)2(OH2)4]0 intermediates led to a rapid condensation via oxolation mechanism into formation of the crystalline ZnO phase. In the presence of both complexes condensation goes via olation mechanism which results in ZnHC.
The growth ZnO and ZnHC particles follows the "non-classical crystallization" concept as it was observed by the combining of the advance in-situ SAXS method and the ex-situ electron microscopy (FE-SEM and TEM). The mechanism predicts the self-assembling of nanobuilding units (5-10 nm) into larger microstructures with prompt crystallisation. At the same time, the growth based on the direct attachment of ions from the solution also occurs in minor extension.


CE-2:IL05  Nanostructured Metal Oxides and Organic-inorganic Hybrid Materials with up-conversion Properties
F. GONELL¹, S. GIMÉNEZ², B. JULIÁN-LÓPEZ¹, ¹Group of Multifunctional Materials, Dep. Inorganic and Organic Chemistry (ESTCE); ²Group of Photovoltaic and Optoelectronic Devices, Dep. Physics (ESTCE), Universitat Jaume I, Castellón, Spain

The ability of lanthanide-doped nanostructures to efficiently up-convert NIR radiation into shorter wavelengths has opened new possibilities not only in photonics but also in photovoltaics, sensors, ceramics and biomedical applications.   
Most of the literature is devoted to up-converting (UC) metal fluorides such as NaYF4 because they are by far the most efficient structures. However, some drawbacks limit their industrial use such as: the high cost of the fluoride precursors, the low chemical and thermal stability of the structures, and the difficulty in terms of synthesis and processing steps, thus increasing costs and fabrication time. Therefore, inexpensive and chemically stable UC metal oxides have emerged as promising candidates to substitute fluoride-based materials.
The control over size, shape, crystalline phase and composition through adequate solution-based synthetic routes allows the enhancement of the UC properties required for high performance materials. Furthermore, these inorganic structures can be embedded and/or chemically-linked to organic moieties thus leading to multifunctional hybrid organic-inorganic nanocomposites. The main advantages of these materials are their easy shaping and processing, and their tunable mechanical, thermal and chemical properties.
In this presentation, the most intriguing features of nanostructured metal oxides as well as organic-inorganic hybrid materials exhibiting up-converting properties prepared in our group will be presented. Interesting aspects concerning the solution-processing techniques, nanostructure and optical response will be discussed. Some examples of their application in the field of energy, photonics and ceramics will also be examined.


CE-2:IL06  Metal Oxides as Protein Mimics
W. TREMEL, Johannes Gutenberg-Universität Mainz, Mainz, Germany

Manufactured nanostructures that mimic enzymes are of great interest as they potentially have improved properties relative to native enzymes, such as greater resistance to extremes of pH and temperature and lower sensitivity to proteases. These enzymatic activities look like the intrinsic properties for metals or metal oxides NPs and the antioxidative enzymatic activities of these NPs have shown great potential in prevention of oxidative stress associated cell death and disease progression in various experimental models [1].
We have studied the biomimetic properties of V₂O₅, MoO₃, Mn₃O₄ and MnO nanoparticles. V₂O₅ nanoparticles catalyze peroxidative reactions in aqueous media and other solvents. The reactions catalyzed by the V₂O₅ nanoparticles follow a Michaelis-Menten behavior with an excellent catalytic activity superior in comparison to natural vanadium haloperoxidase (V-HPO) and horseradish peroxidases (HRP). The kinetic parameters were compared with those of peroxidase and haloperoxidase enzymes. The new nanostructured vanadium-based materials are re-usable and retain their catalytic activity in different organic solvents (up to 90% v/v), making them a promising catalyst mimic of peroxidases [2].
V₂O₅ nanoparticles also display an intrinsic biomimetic halogenating activity, with an exceptional operational stability and superior catalytic activity compared to their natural V-HPO counterpart. We have demonstrated the ability of V₂O₅ nanoparticles to produce HOBr under seawater conditions (pH 8.1, Br^- and H₂O₂ concentrations). The resulting antibacterial, antifouling and disinfecting properties were demonstrated on surfaces for E. coli bacteria, making V₂O₅ a promising paint preservative component as a replacement for enzymes in antibacterial, antifouling and disinfection formulations in water-based paints [3].
Functionalized molybdenum oxide (MoO₃) nanoparticles can replace intracellularly the enzyme sulfite oxidase (SuOx), a molybdenum-containing enzyme that catalyzes the oxidation of sulfite (SO₃^2-) to sulfate (SO₄^2-) in the terminal degradation step of sulfur containing amino acids and lipids. A deficiency of the mitochondria located SuOx in humans leads to a devastating disorder resulting in early death. To date, no efficient or cost effective therapy is in sight. Suitably functionalized MoO₃ nanoparticles display an intrinsic biomimetic SuOx activity under physiological conditions similar to their natural counterpart, are non-toxic and exclusively target the mitochondria. Chemically induced SuOx knockdown cells were created and treated with catalytically active MoO₃-TPP nanoparticles, recovering their SuOx activity in vitro [4]. We foresee this approach to have the potential for a treatment of SuOx deficient patients or open new avenues for cost-effective therapies for gene induced deficiencies within specific patho-physiological frames.
[1] N.A. Kotov, Science 2010, 330, 188-190.
[2] R. André, F. Natálio, M. Humanes, J. Leppin, K. Heinze, R. Wever, W.E.G. Müller, W. Tremel, Adv. Funct. Mater. 2011, 21, 501-509.
[3] F. Natalio, R. André, A.F. Hartog, B. Stoll, K.P. Jochum, R. Wever, W. Tremel, Nature Nanotechnol. 2012, 7, 530-535.
[4] R. Ragg, F. Natalio, M.N. Tahir, A. Kashyap, S. Strand, D. Strand, W. Tremel, submitted.


CE-2:IL07  Synthesis of Metal Oxide Nanostructures for Optoelectronic Devices
YOON-BONG HAHN, School of Semiconductor and Chemical Engineering, Chonbuk National University, Jeonju, Korea

Metal oxides nanostructures such as ZnO, CuO and TiO2 were synthesized by solution methods and they were utilized for fabrication of optoelectronic devices such as field effect transistors (FETs), hybrid solar cells and light-emitting diodes (LEDs). Their structural and electrical properties were examined with various characterization tools. The FETs based on selectively-and-laterally grown ZnO nanorods exhibited high performances in terms of on-current and mobility. The ZnO-based hybrid solar cells combined with reduced graphene oxides (rGO) showed a substantial increase in power conversion efficiency and the LEDs based on n-ZnO nanorods/p-CuO exhibited white yellowish light emission.


CE-2:L08  Hydrogen Production from Thermochemical Water-Splitting Using Ferrites Prepared by Solution Combustion Synthesis
I. WALTERS, R. SHENDE, J.A. PUSZYNSKI, South Dakota School of Mines and Technology, Chemical and Biological Engineering Department, Rapid City, SD, USA

Currently, there are several methods to produce nano-sized spinel ferrite powders such as sol-gel synthesis and solid state combustion synthesis. These methods have been shown to produce pure ferrites for use in hydrogen generation by thermochemical water-splitting but they tend to be very time consuming. However, solution combustion synthesis (SCS) of nano-sized ferrite materials is a relatively simple task that can produce the same size powders, if not finer, in a more efficient manner. In this study, nickel, zinc, cobalt, and manganese ferrites were synthesized using the SCS method. After synthesis, each ferrite was imaged using SEM analysis, purity was determined using XRD analysis, and specific surface area (SSA) was determined using BET analysis. Each ferrite was then tested over five consecutive thermochemical water-splitting cycles to determine hydrogen production. Nickel ferrite produced significantly higher amounts of hydrogen over the five water-splitting cycles with the other ferrites having very similar results. However, all four ferrites showed a decrease in hydrogen generation in each consecutive water-splitting cycle due to particle grain growth, which was confirmed by BET and SEM analysis.


CE-2:IL09  Wet Chemical Routes to Metal Oxide Nanocrystals and Thin Films for Chemical Sensing
M. EPIFANI, Consiglio Nazionale delle Ricerche, Istituto per la Microelettronica e Microsistemi (CNR-IMM), Lecce, Italy

Sensing devices based on chemoresistive detection are nowadays widespread, but still require further development. Fundamental features such as response to ppb gas concentrations, the selectivity and the understanding of the sensing mechanisms still need to be properly addressed. Technological issues such as low cost processing for mass production also need further breakthrough. Chemical processing may offer powerful alternative pathways to prepare the metal oxide structures onto which such sensing devices are based. In fact it is possible to tailor the properties of the chemical precursors and to easily combine the most powerful features of various chemical routes. Usual problems of traditional processing procedures may be overcome, introducing additional degrees of freedom for controlling the properties of the final material. In this work it will be shown that proper chemical processing can provide: a) metal oxides nanocrystals with hugely enhanced response properties; b) suitable ways to effectively introduce additives and dopants, further boosting the performances of the sensors, c) new materials architectures by combining different oxides; d) convenient and not expensive chemistry for large scale deposition of metal oxide thin films, allowing full microelectronic processing.


CE-2:IL10  Development of Ceramic Dielectric Films for Advanced Power Inverters in Electric Drive Vehicles: Current Status and Challenges
U. BALACHANDRAN, M. NARAYANAN, T.H. LEE, S.E. DORRIS, B. MA, Energy Systems Division, Argonne National Laboratory, Argonne, IL, USA

Future availability of high-temperature power inverters will advance the market share for electric drive vehicles. Capacitors are integral part of vehicle power inverters and they have a significant influence on inverter lifetime, cost, and temperature of operation. Advanced power inverters require capacitors that operate under high voltage conditions at under-hood conditions. The "film-on-foil" approach, where the ceramic dielectric is deposited on base-metal foil, is a promising method for making high-temperature capacitors for electric vehicle applications. We have deposited high-permittivity films of lead lanthanum zirconium titanate (PLZT) on base-metal foils and the measured dielectric constants varied with temperature: from ≈700 at -50ºC to ≈2200 at 250 ºC. The dielectric loss remained fairly constant at ≈0.05-0.08. The breakdown field strength of PLZT films was 2.4 MV/cm. Under 300 V bias, we measured dielectric constant ≈110 and dielectric loss of ≈0.004 (0.4%) at room temperature on a ≈3-μm-thick PLZT film. The current status and future challenges in developing high-temperature, high-dielectric constant ceramic dielectric films for electric drive vehicles will be presented in this talk. Work supported by the U.S. Department of Energy, Vehicle Technologies Program.


CE-2:IL11  Metal Oxide Nanopowders for Photocatalytical Applications
T. GRAULE¹, K.A. MICHALOW-MAUKE^{1, 2}, ¹Empa Swiss Federal Laboratories for Materials Science and Technology, Laboratory for High Performance Ceramics, Duebendorf, Switzerland; ²Paul Scherrer Institute, Villigen PSI, Switzerland

Photocatalytic processes are successfully applied as a waste-free route of the hydrogen production and additives-free way of air and water purification. The main obstacle in broader application of the photocatalysis is the lack of efficient photocatalysts, which could be activated by a wide spectrum of solar energy. Commonly used TiO2 suffers from too wide band gap energy (3.0 - 3.2 eV), which allows to absorb only a narrow range of UV energy that makes only 3 - 5 % of total solar energy spectrum. Band gap modification e.g. by metal doping is one of the ways to improve solar energy conversion. W-, Cr- and Fe-doped TiO2 nanopowders with high crystallinity were obtained by means of flame spray synthesis (FSS). TiO2-W consists mainly of anatase and in case of TiO2 doped with Cr or Fe the ratio of anatase to rutile decreases with the increment of dopant concentration (TEM, XRD). All dopants modified the optical properties of TiO2 as observed by diffuse reflectance spectroscopy (DRS). Cr and Fe dopants significantly improved the light absorption in the visible range where effect of W doping was moderate. However, this donor doping resulted in improved photoactivity under applied UVA (λmax.= 355 nm) and Vis (λmax.= 435 nm) irradiation.


CE-2:L12  Synthesis and Aggregation of In2O3 Nanoparticles: Impact of Process Parameters on Stoichiometry Changes and Optical Properties
N. SIEDL, P. GÜGEL, Institute of Particle Technology, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany; O. DIWALD, Department of Materials Science and Physics, University of Salzburg, Salzburg, Austria

Metal organic chemical vapor synthesis provides agglomerated In2O3 nanoparticles with a low abundance of particle-particle interfaces. Via exposure to bulk water and subsequent dehydration treatment these powders can be transformed into networks of aggregated nanoparticles. Two major effects arise from the associated emergence of particle-particle interfaces: an enhanced susceptibility to annealing induced n-type doping and a significant a red shift of the optical absorption threshold by 0.2 eV. On the basis of control experiments with pure water we further explored the impact of the environmental gas atmosphere during annealing on the integral ensemble properties. We found that residual water vapor promotes the mutual attraction of particles, facilitates their condensation and generates particle-particle interfaces. This work may prove to be of great value for the reproducible production and formulation of percolating metal oxide nanoparticle networks with high control over particle aggregation state, on the one hand, and n-type conductivity as well as optical properties, on the other.

 
Session CE-3 - Functional Materials and Sustainability

CE-3:IL01  Engineering New Properties at Intrinsic and Artificial Oxide Interfaces
P. PARUCH, DPMC-MaNEP, University of Geneva, Geneva, Switzerland

In perovskite heterostructures, the complex interplay between many possible instabilities, coupled with electrostatic and strain boundary conditions, provides almost endless possibilities for controllably tuning the functional properties of these "articial materials". In ferroics, naturally occuring domain walls can likewise present novel properties, absent from the parent materials.
Here, we focus first on epitaxial BiFeO3/LaFeO3 superlattices, whose phase diagram displays three distinct regions as a function of BiFeO3 fraction, with ferroelectric and paraelectric phases at its extremities, and a complex intermediate region with unusual, mixed functional behavior, most likely due to competing phases driven by substitution with a same-size central ion, whose control could provide a route for the design of high response artificial materials. [1]
Secondly, we present scanned probe microscopy studies of conduction at 180° domain walls in epitaxial Pb(Zr,Ti)O3 thin films [2], in which we demonstrate reversible switching between a conducting and insulating state as a function of defect doping, in particular by varying the oxygen vacancy density [3].
References:
[1] Rispens et al., submitted (2013)
[2] Guyonnet et al., Adv. Mat. 23, 5377 (2011)
[8] Gaponenko et al., submitted (2013)


CE-3:IL02  Self-cleaning and Anti-fogging Surfaces Based on Nanostructured Metal Oxides
U. LAVRENCIC STANGAR, F. FRESNO, M. KETE, M. TASBIHI, Laboratory for Environmental Research, University of Nova Gorica, Slovenia; A. GASPAROTTO, C. MACCATO, Department of Chemistry, Padova University and INSTM, Italy; D. BARRECA, IENI-CNR and INSTM, Department of Chemistry, Padova University, Italy

Self-cleaning and anti-fogging technology is already used in a variety of the products today, among which glazing products prevail. Their function is based on the two principles, either hydrophobic (Lotus effect) or photocatalytic hydrophilic principle. In the latter case, self-cleaning action is based on the combination of photocatalysis and photoinduced superhydrophilicity, where dirt removal by uniform spreading of water over the whole surface is improved with photocatalytic decomposition of organic contaminants. There is a big room to play and a huge potential to improve the properties of existing self-cleaning and anti-fogging surfaces by designing and tailoring new nanoarchitectures of the light-activated thin films. In this lecture we report about the latest achievements and relevance of nanostructured metal oxide surfaces for specific application in photocatalytic self cleaning. The emphasis will be given to the preparation and structure-property relationship of nanocomposite materials based on TiO2, TiO2-SiO2, ZnO and ZnO/Co3O4. The emphasis will also be given to determination of photocatalytic self-cleaning activity by quantitative and sensitive methods such as fluorescence detection of the first degradation product of terephthalic acid.


CE-3:L03  Advanced Fe2O3 Nanomaterials for Solar-Activated H2 Generation
G. CARRARO, C. MACCATO, A. GASPAROTTO, Department of Chemistry, Padova University and INSTM, Italy; D. Barreca, IENI-CNR and INSTM, Department of Chemistry, Padova University, Italy; P. FORNASIERO, V. GOMBAC, T. MONTINI, Department of Chemical and Pharmaceutical Sciences, ICCOM-CNR and INSTM, Trieste University, Italy; O.I. LEBEDEV, Laboratoire CRISMAT, CNRS-ENSICAEN, France; S. TURNER, G. VAN TENDELOO, EMAT, Antwerp University, Belgium

In the last years, α-Fe2O3 (hematite) has attracted a great attention as active photocatalytic material hydrogen generation. Yet, despite its popularity, α-Fe2O3 presents several intrinsic drawbacks that strongly limit its functional performances. In this context, an appealing option is represented by the preparation of β- and ε-Fe2O3, two iron oxide polymorphs that have recently emerged as a promising alternative to hematite. Herein, we report on a versatile chemical vapor deposition approach enabling the selective fabrication of α-, β- and ε-Fe2O3. Interestingly, the latter two phases possess a photocatalytic activity remarkably higher than α-Fe2O3 in the sunlight-assisted H2 production from aqueous solutions of various oxygenated organic compounds.


CE-3:IL06  EISA, Click Chemistry and Ink-jet printing: a Fruitful Association for the Fabrication of Innovative Biosensors
F. ROSSIGNOL, O. DE LOS COBOS, J. GRAFFION, M. LEJEUNE, M. COLAS, Laboratoire de Science des Procedes Ceramiques et de Traitements de Surface (SPCTS), UMR-CNRS 7315, CEC, Limoges, France; F. LALLOUE, H. AKIL, Homeostasie Cellulaire et Pathologies, EA 3842, Faculte de Medecine, Limoges Cedex, France; C. CARRION, Plateforme Cytometrie-Imagerie-Mathematiques (CIM), UMR-CNRS 6101, Faculte de medecine, Limoges Cedex, France; P. FAUGERAS, Société DIOPTIK, Ester Technopole, Limoges, France; C. BOISSIÈRE, C. SANCHEZ, Laboratoire de Chimie de la Matiere Condensee de Paris, UMR CNRS 7574, Universite Pierre et Marie Curie Paris VI, College de France, Paris Cedex, France; X. CATTOEN, M. WONG CHI MAN, J.-O. DURAND, Institut Charles Gerhardt Montpellier (ICGM), UMR-CNRS 5253 (UM2-ENSCM-UM1), Montpellier, France

Specific substrates can be multifunctionalized to serve as smart devices for recognition of (tumoral) biomarkers. The device fabrication needs combining ink-jet printing (IJP), evaporation induced self assembly (EISA) and click chemistry. More specifically, mesoporous silica microdots are first deposited onto a patterned substrate, the structuring of the porosity being achieved by EISA. Then, click chemistry is used to anchor bio-receptors onto the mesoporous silica surface. Those bio-receptors are labeled with specific fluorophores that are chosen so that Fluorescence Resonance Energy Transfer (FRET) detection is made possible when antigens and antibodies interact. Fluorescence excitation and FRET signal read-out are performed directly through the substrate. The same approach can also be performed to implement at the same time photodynamic therapy (PDT) paving the way to "theranostic" devices.


CE-3:L07  Novel Adaptive Functional Materials: from Chemo-Mechano-Chemistry to Homeostasis
X. HE^1,2, M. AIZENBERG², O. KUKSENOK³, L.D. ZARZAR⁴, A. SHASTRI⁴, A.C. BALAZS³, J. AIZENBERG^{1, 2, 4}, ¹School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA; ²Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA, USA; ³Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, PA, USA; ⁴Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA

New adaptive and self-regulating functional materials having chemo-mechano-chemical transduction at their core is described. Arrays of high-aspect-ratio microstructures decorated with chemicals and embedded in a liquid bilayer allow one to utilize highly controlled mechanical actuation, driven by a responsive hydrogel, as a precise switch for physical and chemical processes, such as fluorescence quenching, a gas-evolving inorganic reaction, or a variety of catalytic reactions having different outputs. A positive feedback loop coupling heat evolution from exothermic catalytic reactions with mechanical action of a temperature-responsive gel, provides a basis for a modular, highly tunable artificial homeostatic device capable of autonomously maintaining temperature within a narrow range. Such self-regulating adaptively reconfigurable tunable system (SMARTS) can find applications in temperature control, energy conversion, biomolecule and cell sorting, catch and release of particles, tunable optics, and microrobotics.
Reference:
X. He, M. Aizenberg, O. Kuksenok, L. D. Zarzar, A. Shastri, A. C. Balazs & J. Aizenberg. Nature 487, 214-218 (12 July 2012)


CE-3:L08  Bifunctional TiO2/Ag3PO4/Graphene Composites with Highly Efficient Visible Light Photocatalytic Performance and Excellent Bactericidal Activity
JIELING QIN, XIAOFEI YANG, School of Materials Science and Engineering, Jiangsu University, Zhenjiang, China

We report the preparation of novel TiO2/Ag3PO4/graphene (TiO2/Ag3PO4/GR) composites via the combination of ion-exchange process and hydrothermal approach. The fabrication has been achieved through the electrostatic-driven assembly of Ag+ on graphene oxide sheets, followed by controlled growth of Ag3PO4 and the deposition of TiO2 on GO surface. The subsequent hydrothermal treatment leads to the generation of TiO2/Ag3PO4/GR composites with well-defined structures. The composites exhibit highly efficient visible light photocatalytic degradation toward organic dye and show excellent bactericidal performance.
It is the first report on the production of bifunctional metal oxide/Ag3PO4/GR materials with highly efficient photocatalytic performance and excellent bactericidal activity. The improved photocatalytic activity is attributed to the effective separation of photoexcited electron-hole pairs and fast charge transfer in the composite, while its excellent bactericidal performance is believed to come from intrinsic bacterial inactivation of Ag3PO4 and photo-induced antibacterial activity of active oxygen-containing radicals generated in the irradiated system. The TiO2/Ag3PO4/GR composite significantly decreases the percentage of expensive Ag-containing material while reveals better photocatalytic and antibacterial performance than Ag3PO4, providing new insights into the low-cost, large-scale production of Ag3PO4-based function materials for practical applications.


CE-3:IL10  Controlled Functionalization of Surfaces towards Molecularly-defined Surface Sites
C. COPERET, Department of Chemistry and Applied Biosciences, ETH Zürich, Switzerland

This lecture will show how it is possible to combine the advantages of homogeneous and heterogeneous catalysts by the controlled functionalization of the surfaces of oxide and hybrid materials and by the characterization of surface species at the molecular level, thus allowing more predictive approaches.
We will illustrate the power of this approach with the development of well-defined "single-sites", whose performance and stability can be far above those displayed by homogeneous and heterogeneous catalysts, e.g. alkene metathesis.
With our current level of understanding of surfaces, we will also discuss new directions in this field: understanding defect sites of surfaces and metal-support interactions at the molecular level, introducing diversity in oxide chemistry, controlling the growth of nanoparticles, the development of Surface Enhanced NMR spectroscopy and the potential of this approach in imaging technologies.


CE-3:L12  Properties of the Metallic Glass Thin Films Synthesized with Multi-component Alloyed Target for Bipolar Plate in PEM Fuel Cell
JUHYUN SUN¹, J.Y. CHOI², K.I. MOON², C.H. LEE¹, S.Y. SHIN¹, ¹Advanced Fusion Process R&D Group, Korea Institute of Industrial Technology, Incheon, Republic of Korea; ²Plasma Enhanced Technology Development Team, Korea Institute of Industrial Technology, Incheon, Republic of Korea

Metallic materials for PEM fuel cell have advantages over graphite ones due to their higher mechanical strength, better electrical conductivity and lower production cost. However, they have significant drawbacks such as susceptibility to corrosion in the acid and humid environment. Recently some research groups have tried to use metallic glass alloys in bipolar plates because of their unique properties such as higher mechanical strength and corrosion resistances.
In this study, we tried to synthesize the metallic glass thin films and investigated their electrical and corrosion properties. Zr-Al-Cu and Zr-Co-Cu alloys that have glass forming ability (GFA) over 1mm were used as target materials. Metallic glass thin films were deposited on SUS316L substrate by DC magnetron sputtering process with alloyed single target in Ar gas atmosphere. Current density of the films were under 10-8 A/cm2 in both anodic and cathodic atmosphere and there were no changes of the current density in the range of 0.6 ~ 1.2V which is operating voltage of the fuel cell stack. But there was no significant improvement of the electrical properties. In order to enhance the electrical properties of the films, cleaning process with respect to removing oxide layer on stainless steel plate were investigated.


CE-3:L13  Carbon-metal Nanocomposites for Supercapacitor Application
N.M. SULEIMANOV, S.M. KHANTIMEROV, I.A. FAIZRAHMANOV, Zavoisky Physical Technical Institute of Russian Academy of Sciences, Kazan, Russia

In this report the approach is developed where the carbon nanotube - metallic nanoparticles composites are used as the material of electrodes for electrochemical capacitors based on the double electric layer and pseudo-capacitance effect. To improve the pseudo-capacitance properties, ethanol as auxiliary reagent is added to the electrolyte to enhance the redox reaction. As active electrode material two types of carbon-metal composites: carbon nanotube - Ni nanoparticle composites (CNT-Ni) and carbon-palladium hybrid films were prepared and studied. The peak on the potentiodynamic curve for CNT-Ni composite electrode in alkaline solutions of ethanol is observed which is ascribed to the ethanol oxidation in alkaline medium. The results obtained are discussed from the point of view of both the double layer capacitance and pseudo capacitance. The carbon-palladium films were prepared by ion evaporation of integrated targets consisting of graphite and metallic palladium. Electron microscopy measurements showed that the nanoparticles of palladium were formed in the graphite matrix with average dimension of about 3 nm. The contribution of Pd nanoparticles to the electrochemical processes going on the surface of films is considered from the point of view of their electrochemical properties.
 
 
Poster Presentations

CE:P01  Surface-Modification of Nanostructured Fe2O3 Polymorphs for Light-Assisted Functional Applications
A. GASPAROTTO, G. CARRARO, C. MACCATO, Department of Chemistry, Padova University and INSTM, Italy; D. BARRECA, IENI-CNR and INSTM, Department of Chemistry, Padova University, Italy; F. ROSSI, G. SALVIATI, IMEM-CNR, Parco Area delle Scienze, Parma, Italy; M. TALLARIDA, C. DAS, D. SCHMEISSER, Brandenburg University of Technology, Germany; F. FRESNO, D. KORTE, U. LAVRENCIC STANGAR, M. FRANKO, Laboratory for Environmental Research, University of Nova Gorica, Slovenia

In the present work, a two-step synthetic strategy has been developed for the surface modification of Fe2O3-based nanosystems. Specifically, alpha-Fe2O3 or epsilon-Fe2O3 deposits were first synthesized by CVD under optimized conditions, and subsequently functionalized with an ultrathin titanomagnetite (Fe3-xTixO4) layer via ALD. An extensive multi-technique material characterization evidenced that the control of Fe2O3/Fe3-xTixO4 interfacial interactions was the key tool to achieve enhanced light-assisted (e.g. antifogging, self-cleaning) properties, as demonstrated by preliminary water contact angle and photocatalytic tests.


CE:P02  Self-propagation Low Temperature Flameless Combustion Synthesis of Ni and Al Nanoparticles: Time-resolved XRD Study
YU. M. MIKHAILOV¹, V.V. ALESHIN¹, A.M. KOLESNIKOVA¹, D.YU. KOVALEV², V.I. PONOMAREV²; ¹Institute of Problems of Chemical Physics RAS, Chernogolovka, Russia; ²Institute of Structural Macrokinetics and Materials Science, Chernogolovka, Russia

Formation of Ni and Ag nanoparticles in the wave of flameless combustion (smoldering) of cellulose nitrate (CN) was studied by time-resolved XRD. The smoldering of CN containing an organic binder and nickel hydroxycarbonate (NiOHCO3) or silver carbonate (Ag2CO3) as precursors was found to produce Ni or Ag nanoparticles. The formation of the Ni nanocrystals proceeded via some diffraction-silent intermediate state of the system. During formation of the Ag nanoparticles, the diffraction patterns exhibited signals from the precursor and newly formed silver particles but no signs of diffraction-silent intermediate.


CE:P03  Compositional Designs for High Performance Antifingerprint Coated Concealed Cistern Control Panels
A. TUNALI, N. TAMSU SELLI, Eczacibasi Building Product Co., Vitra Innovation Center, Bilecik, Turkey

Working principle of the concealed cistern control panels is the system that flush the water into the reservoir to flow into the bowl when the pressing the button on the panel. After pressing by hands, the buttons and panel surfaces became dirty by fingerprints. For cleaning the panels cleaning chemicals are required for cleaning the fingerprints. This situation leads extra cost and as well as time consuming process. For this reason antifingerprint coated panels are required. In this study, antifingerprint coating systems were developed and to improve the coating performance such as mechanical and chemical resistance, different polyurethane composition ratios were studied and effectiveness of the coating systems were investigated by using characterization methods (SEM, EDX, FTIR).


CE:P04  Sol-Gel Derived Two-dimensional Nanostructures of Calcium Phosphate Composites
A. PRICHODKO, V. JONAUSKE, M. CEPENKO, A. BEGANSKIENE, A. KAREIVA, Department of Inorganic Chemistry, Vilnius University, Vilnius, Lithuania

Calcium hydroxyapatite (Ca10(PO4)6(OH)2, CHAp), tricalcium phosphate (Ca3(PO4)2, TCP) and calcium oxide (CaO) are the main components of inorganic part of human bones. Such synthetic nanocomposites could be very important implantable materials and as substitute material for human hard tissues (bones and teeth). CHAp/TCP nanocomposite possesses required biocompatibility, bioactivity and osteoconductivity coming from the analogy to the mineral components of natural bones.
Aqueous sol-gel chemistry route has been developed to prepare nanostructured CHAp/TCP thin films on different substrates. The final samples were obtained by calcination of coatings for different time at 900-1000 °C. For the characterization of surface properties, the X-ray powder diffraction (XRD) analysis, scanning electron microscopy (SEM), atomic force microscopy (AFM) and the contact angle measurements were recorded. It was shown that synthesis parameters can be used to control the phase purity and morphology of the bioceramic thin films.
The financial support to A.P. from the Research Council of Lithuania under project "Postdoctoral Fellowship Implementation in Lithuania" (No. 004/102) is acknowleged.


CE:P05  Preparation and Properties of Silica/poly(vinyl alcohol) Organic-inorganic Hybrid Gas Barrier Films with Cross-linked Structure
K. KURAOKA, R. ABE, Y. KINOSHITA, Kobe University, Kobe city, Hyogo, Japan

Silica/poly(vinyl alcohol) (PVA) organic-inorganic hybrid gas barrier films with cross-linked structure were prepared by sol-gel method using silicon alkoxides, PVA and 1, 2, 4, 5- benzenetetracarboxylic acid (PM) or tetrahydrofuran- 2, 3, 4, 5-tetracarboxylic acid (THC) as a crosslinking agent on polypropylene (PP) or polyethylene terephthalate (PET) substrates. Oxygen permeation and water vapor permeation through the films were measured. Oxygen permeability coefficients of the hybrids were small and about one-tenth of those of poly(vinylidene chloride) (PVDC) and water vapor transmission rate of the hybrid was the same order of PVDC. Pencil hardnesses (50g load) of the PET with the hybrid films were 3H. These values were higher than that of PET (2H). These properties were thought to be due to well dispersion of inorganic segments (silica) and organic segments (PVA) at molecular level and the formation of cross-linked structure in the hybrid. From the results, it was found that the organic-inorganic hybrids could be applicable to gas barrier films.


CE:P06  Sol-gel Method for Producing Superconducting Materials of System Y-Ba-Cu-O
B.I. BOGDANOV, P.S. PASHEV, Y.H. HRISTOV, R.S. RAYKOVA, University "Prof. d-r Assen Zlatarov", Department of Inorganic Substances and Silicates, Bougas, Bulgaria

The aim of this work is to obtain batches for high temperature superconducting ceramics of the system Y-Ba-Cu-O by sol-gel method. Starting materials are converted to nitrates by treatment with concentrated nitric acid. NH3 was used to neutralize the resulting solutions and facilitate the complex formation. Highly homogeneous and viscous gel without any precipitation was obtained. The thermal decomposition of metal-organic precursor has been studied using IR and DTA. This process is highly reproducible and leads to powders with excellent homogeneity and small particle size, which improve the synthesis of superconducting materials.


CE:P07  The Consolidated Nanocomposite Materials with the Defined Properties
G. SEMCHENKO¹, E.S. GEVORKYAN², ¹National Technical University "Kharkov Polytechnic Institute"; ²Ukrainian State Academy of Railway Transport, Kharkov, Ukraine

Association of synthesis' methods of organic and inorganic chemistry, sol-gel method and mechanochemistry, allowing to control the processes of synthesis of the specified phases at molecular level, give an opportunity to create high-efficiency composite materials.
Mechanical-chemical synthesis of nanoparticles of β-SiC by silicon alcoxide allowed to create composite materials on the basis of SiC, B4C, Si3N4, self-reinforced by nanoparticles of β-SiC, with bending durability no less than 650 МPа and crack resistance 6,5-7,9 МPа.m0,5.
By hot-pressing (1200-1400 °С, rate of temperature increase 400 degree/minute) also has been synthesized ZrO2 - WC nanomaterials from a mixture of nanopowder of WC and nanopowder of ZrO2, got by thermal decomposition of zirconium salts, with bending strength 250-300 МPа, crack resistance 20-25 МPа.m0,5, hardness 22-24 GPа and heat conductivity 30-35 W/m.К.
Created hybrid organic-inorganic composites on the basis of calcium phosphate matrix, self-reinforced by nanocrystals of periclase, have 3-4,5 time higher durability and improved technological and operating characteristics.


CE:P11  Some Properties of Uranium Nitrides Produced by Spark-Plasma and Electro Discharge Sintering
V.G. BARANOV, D.P. SHORNIKOV, M.S. YURLOVA, B.A. TARASOV, S.N. NIKITIN, T.V. JAKUTKINA, NRNU MEPHI, Moscow, Russia

Nitride fuel has been proposed as a fuel for fast reactor of new generation (Generation IV). Here we discuss preliminary results of research and production uranium of nitrides pellets by spark-plasma and electro pulse methods. The powder of uranium nitride was synthesized by hydriding - nitriding methods from metallic uranium. The prepared nitride powders were packed to graphite matrix with molybdenum protective layer and sintered in SPS in a flow of argon gas. The sintering temperature was 1400-1600 °C and pressure was 40 MPa for all the samples. Holding time was set to 10 min for all the samples. Consequently, the SPS process, which includes the heating and holding processes, finished within 5 and 10 min for UN samples. In the case of electro-discharge sintering uranium nitrides powder was packed to ceramics matrix with molybdenum punches (diameter 8-10 mm). The pressure was 130-180 MPa and discharge voltage 3,0-5,0 kV. The production of fuel pellets (density 85-95 % from theoretical) with a set of geometrical sizes from high dispersion powder of uranium nitride is shown and some properties uranium nitrides fuel pallets, for example: density, porosity and thermo conductivity, are reported.


CE:P13  Photocatalytic Water-Splitting using Modified Heterojunction TiO2 Nanotube Arrays
BONGSOO KIM¹, SEUNGBUM HONG^{1, 2}, KWANGSOO NO¹, ¹Department of Materials Science and Engineering, KAIST, Daejeon, South Korea; ²Nanoscience and Technology Division, Argonne National Laboratory, Lemont, IL, USA

We present a novel fabrication method of modified TiO2 nanotube arrays and its applicability in water splitting for hydrogen production and degradation of organic contaminants in water. Self-aligned TiO2 nanotube arrays were grown by anodization of Ti foils in ethylene glycol containing NH4F. In order to enhance the performance, TiO2 nanotube arrays were structurally modified to have both ends of the nanotube open using an electrochemical method. The obstacles that limit the efficiency of water splitting using TiO2 are recombination of electron-hole pairs inside the bulk and the band gap of 3.2 eV that is not absorbing most of the visible light. The structurally modified TiO2 nanotube arrays allow for hetero-junction with other materials over the whole surface of the TiO2 nanotubes, which may tackle the problems. We plan to fill the inside of the open-ended TiO2 nanotube arrays with CuInS2 quantum dots and metal nanoparticles as the materials for the hetero-junction in order to enhance the water splitting performance under visible light.


CE:P15  Effects of Particle Size and Solid Solution of Al2O3(A) / CexZr1-xO2(CZ) on the Oxygen Release Capability of the Composite Powder
FU-SU YEN, CHUNG-CHE WEI, PEI-CHING YU, Department of Resources Engineering, National Cheng Kung University,Taiwan; SHIAN REN YANG, Department of Cosmetic Applications & Management, Far East University, Taiwan

A/CZ is a composite powder of Al2O3(A) and CexZr1-xO2(CZ). Being an oxygen storage material, it is adopted in oxidizing hydrocarbon at cold start emission for automotive catalytic converter. In this study, the particle size of CZ and the solid solution of CexZr1-xO2(CZ) that influence and are related to the oxygen release capacity of the A/CZ powders were examined. A/CZ powders were fabricated by mixing alumina (doped with zirconia)、(NH4)2Ce(NO3)6 and ZrO(NO3)2.6H2O in a stoichiometric Al2O3/Ce/Zr mole ratios of 5/0.6/0.4 and 5/0.6/0. The mixtures then treated by heating to temperature 750℃ and 900℃ for various durations. Examination then were performed by XRD for phase identification and Scherrer diameter determination. TPR (Temperature Programmed Record) techniques were used for evaluating oxygen release capacity of the thermal-treated mixtures. It is found that an increase in particle size of CZ would result in the lowering of the oxygen release capability for A/CZ. Increaing the fractions of solid solution in A/CZ eventually raises the capability. Furthermore, the oxygen release capability of A/CZ is dominated by the presence of solid solution rather than the particle of CZ.


CE:P16  Thermoelectric Properties of Hexagonal Barium Titanates
S. YASUI, Y. ISHIMOTO, T. SHIMIZU, M. ITOH, Tokyo Institute of Technology, Yokohama, Japan

Thermoelectric materials have been widely investigated for one of the green energy candidates. Bi-Te and Pb-Te based thermoelectric materials are used due to their superior property for applications. However, these materials include toxic elements and are not environmentally friendly. Therefore, a lot of alternatives have been studied. From the material science of view, one of the important parameter, thermal conductivity, is needed to be controlled for obtaining superior property. Thermal conductivity is basically dependent on phonons and electrons in the structure. In this study, we focus on conductive hexagonal BaTiO3 (h-BTO). Single crystal h-BTO was prepared by Floating-Zone (FZ) method. Stacking structure of hexagonal [001]-orientation showed smaller thermal conductivity than that of [100]-orientation. Then, oxygen vacancy in h-BTO single crystals was controlled by annealing condition. As a results, electrical and thermal conductivities increased with increasing oxygen vacancy, however Seebeck coefficient decreased. Figure of merit, ZT, increased with increasing oxygen vacancies.


CE:P17  Innovative Synthesis of Nanostructured Complex Gadolinium Ferrites with High Temperature Solid State Reactions
I.V. CHISLOVA, I.A. ZVEREVA, Saint-Petersburg University, Saint-Petersburg, Russia; T.F. SHESHKO, Peoples Friendship University of Russia, Moscow, Russia

In this report we present results for nanodispersed perovskite-like ferrites GdFeO3, GdSrFeO4, Gd2SrFe2O7 synthesized by sol-gel technology. These oxides are highly selective catalysts for the production of light olefins from carbon oxides. GdFeO3, GdSrFeO4 and Gd2SrFe2O7 were synthesized by high temperature solid state reactions and by sol-gel technology performed using citrate-nitrate techniques.
Simultaneous thermal analysis (TG and DSC) has been used for the determination of the temperature of formation of complex oxides, Powder X-ray diffraction and scanning electron microscopy - for the determination of the structure and morphology of synthesized samples, Photon correlation spectroscopy - for evaluation of average particle size and size distribution. Valent state of iron atoms have been investigated using Mössbauer spectroscopy.
The results indicate that complex ferrites obtained by sol-gel method exist not only in ultradispersed state but also in heterovalent iron state (Fe+3 and Fe+4) with oxygen vacancies that is necessary for catalysis. The possibility of producing of olefins from the mixture of hydrogen and carbon mono- and dioxides and the influence of the method of production on the activity of complex ferrites and their selectivity have been investigated.