| 1. |
- Adebahr, Josefina, 1973, et al.
(författare)
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Lithium coordination and mobility in gel electrolytes based on an acrylate polymer with ethylene oxide side chains
- 2003
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Ingår i: Journal of Materials Chemistry. - : Royal Society of Chemistry (RSC). - 1364-5501 .- 0959-9428. ; 13:4, s. 814-817
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Tidskriftsartikel (refereegranskat)abstract
- Multinuclear NMR has been used to investigate the structure and mobility of a series of polymer gel electrolytes. The co-polymers used as matrixes in the gels have acrylate backbones and side chains of ethylene oxide, where the length of the side chains has been varied, while the ratio of acrylate to ethylene oxide has been kept constant. The electrolyte is a mixture of lithium perchlorate and two solvents, ethylene carbonate and gamma butyrolactone. 13 C spectra of the different gel electrolytes shows that both solvents interact with the salt, and that the strength of the interaction increases with decreasing length of the polymer side chains. It also appears that the lithium ions show no selectivity between the two types of solvent. Furthermore, the lithium chemical shift moves progressively upfield with increasing length of the side chains, showing a gradual change in interaction from lithium-solvent to lithium-(ethylene oxide).
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| 2. |
- Akhtar, Farid, et al.
(författare)
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Hierarchically porous binder-free silicalite-1 discs : a novel support for all-zeolite membranes
- 2011
-
Ingår i: Journal of Materials Chemistry. - 0959-9428 .- 1364-5501. ; 21:24, s. 8822-8828
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Tidskriftsartikel (refereegranskat)abstract
- Thermal expansion mismatch between the zeolite film and the support is an important cause for the formation of defects and cracks during the fabrication and use of zeolite membranes. We have studied how silicalite-1 discs with a permeability comparable to commercially available alumina supports can be produced by pulsed current processing (PCP) as a novel substrate for all-zeolite membranes. Hierarchically porous and mechanically strong membrane supports where the surface area and crystallography of the silicalite-1 particles were maintained could be obtained by carefully controlling the thermal treatment during PCP consolidation. In situ X-ray diffraction and dilatometry showed that the coefficient of thermal expansion (CTE) of the silicalite-1 substrate was negative in the temperature range 200-800 degrees C while the commonly used alumina substrate displayed a positive CTE. The critical temperature variation, Delta T, and thicknesses for crack-free supported zeolite films with a negative CTE were estimated using a fracture energy model. Zeolite films with a thickness of 1 mu m can only sustain a relatively modest Delta T of 100 degrees when supported onto alumina substrates while the all-zeolite membranes can support temperature variations above 500 degrees
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| 3. |
- Akhtar, Farid, et al.
(författare)
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Hierarchically porous binder-free silicalite-1 discs : a novel support for all-zeolite membranes
- 2011
-
Ingår i: Journal of Materials Chemistry. - : Royal Society of Chemistry (RSC). - 0959-9428 .- 1364-5501. ; 21:24, s. 8822-8828
-
Tidskriftsartikel (refereegranskat)abstract
- Thermal expansion mismatch between the zeolite film and the support is an important cause for the formation of defects and cracks during the fabrication and use of zeolite membranes. We have studied how silicalite-1 discs with a permeability comparable to commercially available alumina supports can be produced by pulsed current processing (PCP) as a novel substrate for all-zeolite membranes. Hierarchically porous and mechanically strong membrane supports where the surface area and crystallography of the silicalite-1 particles were maintained could be obtained by carefully controlling the thermal treatment during PCP consolidation. In situ X-ray diffraction and dilatometry showed that the coefficient of thermal expansion (CTE) of the silicalite-1 substrate was negative in the temperature range 200-800 degrees C while the commonly used alumina substrate displayed a positive CTE. The critical temperature variation, Delta T, and thicknesses for crack-free supported zeolite films with a negative CTE were estimated using a fracture energy model. Zeolite films with a thickness of 1 mu m can only sustain a relatively modest Delta T of 100 degrees when supported onto alumina substrates while the all-zeolite membranes can support temperature variations above 500 degrees.
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| 4. |
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| 5. |
- Andersson, Nina, et al.
(författare)
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One-Pot Synthesis of Well-Ordered Mesoporous Magnetic Carriers
- 2007
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Ingår i: Journal of Materials Chemistry. - : Royal Society of Chemistry (RSC). - 0959-9428 .- 1364-5501. ; 17:26, s. 2700-2705
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Tidskriftsartikel (refereegranskat)abstract
- The facile preparation of a mesoporous magnetic carrier technology is demonstrated. The micron-sized spherical mesostructured particles are prepared using a newly-developed, one-step, combined emulsion and solvent evaporation (ESE) method. The surfactant-templated silica matrix display a well-ordered internal pore architecture. Very limited pore blocking, and only to a limited degree disordered- or worm-like structures are observed, induced by the iron oxide nanoparticles added to provide the superparamagnetic properties.The iron oxide content was precisely controlled, and the magnetic properties were well preserved during the process. Finally we demonstrate the applicability of the magnetically separable mesoporous material as an adsorbent for specific dissolved materials from dilute aqueous solutions.
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| 6. |
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| 7. |
- Andersson, N, et al.
(författare)
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Photochromic mesostructured silica pigments dispersed in latex films
- 2005
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Ingår i: Journal of Materials Chemistry. - 0959-9428 .- 1364-5501. ; 15:0149-2136, s. 3507-3513
-
Tidskriftsartikel (refereegranskat)abstract
- We have incorporated the photochromic dyes spiropyran and spirooxazine in surfactant templated mesostructured silica particles. Spherical inorganic–organic hybrid pigments with varying dye content were produced by a one-pot synthesis in an aerosol reactor where the internal mesostructure could be controlled. The mesostructured inorganic–organic hybrid pigments provide a mechanically and chemically rigid framework that protects the dyes and facilitate handling. We show that an organic latex binder can be used to prepare transparent photochromic films of varying thickness. Changing the dye loading in the pigments and the pigment content in the films provides a versatile route for tuning the photochromic response. The pigmented films show both fast and direct photochromism, where the decay time for thermal bleaching is very fast in the case of spirooxazine doped pigments (kSO= 0.094 s–1), being in the range of the best reported values for solid state composites.
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| 8. |
- Antoni, Per, et al.
(författare)
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Europium confined cyclen dendrimers with photophysically active triazoles
- 2008
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Ingår i: Journal of Materials Chemistry. - : Royal Society of Chemistry (RSC). - 0959-9428 .- 1364-5501. ; 18:22, s. 2545-2554
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Tidskriftsartikel (refereegranskat)abstract
- Dendrimers up to the fourth generation (G1-G4) were successfully synthesized via the efficient copper catalyzed 1,3-dipolar cycloaddition between primary alkynes and azides (CuAAC), also referred to as a click reaction. The synthetic protocol involved the preparation of presynthesized dendron wedges that subsequently were attached to a tetra-valent alkyne functional cyclen core. These constructed structures integrated stable triazole groups "intra-locked'' between the cyclen and dendron wedges. The incorporation of a lanthanide metal ion, europium, into the interior of all cyclen dendrimers was monitored by FT-IR. Interestingly, the photophysical results showed that the proximate triazole not only acts as a stable linker but also as a sensitizers, transferring its singlet-singlet excitation in the ultraviolet region (270-290 nm) to the partially filled luminescent lanthanide 4f shell. An increase of luminescence decay time from the lanthanide D-5(0) -> F-7(2) emission was observed with increasing dendrimer size, indicating that the shielding effect of the dendron wedges is important for the relaxation of the photo-excitation and energy transfer. To the best of our knowledge, this is the first time a set of dendron wedges have successfully been attached to a cyclen metal ion cage via the versatile click reaction. Furthermore, the produced triazoles intra-locked in close proximity to the macrocycle core elucidated an interesting photophysical function.
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| 9. |
- Asfaw, Habtom Desta, et al.
(författare)
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Emulsion-templated bicontinuous carbon network electrodes for use in 3D microstructured batteries
- 2013
-
Ingår i: Journal of Materials Chemistry. - United Kingdom. - 0959-9428 .- 1364-5501. ; 1:44, s. 13750-13758
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Tidskriftsartikel (refereegranskat)abstract
- High surface area carbon foams were prepared and characterized for use in 3D structured batteries. Twopotential applications exist for these foams: firstly as an anode and secondly as a current collector supportfor electrode materials. The preparation of the carbon foams by pyrolysis of a high internal phase emulsionpolymer (polyHIPE) resulted in structures with cage sizes of 25 mm and a surface area enhancement pergeometric area of approximately 90 times, close to the optimal configuration for a 3D microstructuredbattery support. The structure was probed using XPS, SEM, BET, XRD and Raman techniques; revealingthat the foams were composed of a disordered carbon with a pore size in the <100 nm range resultingin a BET measured surface area of 433 m2 g-1. A reversible capacity exceeding 3.5 mA h cm2 at acurrent density of 0.37 mA cm-2 was achieved. SEM images of the foams after 50 cycles showed thatthe structure suffered no degradation. Furthermore, the foams were tested as a current collector bydepositing a layer of polyaniline cathode over their surface. High footprint area capacities of500 mA h cm-2 were seen in the voltage range 3.8 to 2.5 V vs. Li and a reasonable rate performancewas observed.
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| 10. |
- Babushkin, Oleg, et al.
(författare)
-
Thermal expansion of hot isostatically pressed hydroxyapatite
- 1994
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Ingår i: Journal of Materials Chemistry. - 0959-9428 .- 1364-5501. ; 4:3, s. 413-415
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Tidskriftsartikel (refereegranskat)abstract
- A dense and transparent hydroxyapatite produced by hot isostatic pressing was investigated with respect to its stability and thermal expansion behaviour in the range 20–1150 °C. The evaluation was made by high-temperature X-ray diffraction in a reconstructed test chamber with a BN sample holder and Pt as an internal (in situ) reference. No degradation of the hydroxyapatite was detected in the range investigated. The lattice parameters, a and c, were determined as a function of temperature. The linear thermal expansion coefficient, determined by dilatometry, was 17.1 × 10–6°C–1, which agreed well with the value 17.3 × 10–6°C–1 obtained by X-ray diffraction.
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| 11. |
- Bhatt, Aarti Sripathi, et al.
(författare)
-
Chitosan/NiO nanocomposites : a potential new dielectric material
- 2011
-
Ingår i: Journal of Materials Chemistry. - : Royal Society of Chemistry (RSC). - 0959-9428 .- 1364-5501. ; 21:35, s. 13490-13497
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Tidskriftsartikel (refereegranskat)abstract
- The study of electrochemical behavior of organic-inorganic nanocomposite materials remains a major challenge for application in energy storage devices. Here, new composite materials of chitosan and NiO nanoparticles have been fabricated. The NiO nanoparticles are well characterized by infrared spectroscopy, X-ray diffraction and transmission electron microscopy. The electrical properties of the films are studied by impedance spectroscopy at different temperatures; and thereby permittivity, electric modulus and conductivity data are obtained. By studying the variations in permittivity and electric modulus spectra with respect to applied frequency signal and temperature, the ionic conductivity of the material is investigated. The Correlated Barrier Hopping model is employed to understand the conduction mechanism. An admirable conductivity of 1.4 x 10(-2) S cm(-1) is obtained for a nanocomposite with 4 wt% NiO content. The activation energies of the composite films decrease with increase in NiO content, from 16.5 to 4.8 kJ mol(-1).
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| 12. |
- Bhatt, Pramod, et al.
(författare)
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Ferromagnetism above room temperature in nickel-tetracyanoethylene thin films
- 2009
-
Ingår i: Journal of Materials Chemistry. - : Royal Society of Chemistry (RSC). - 0959-9428 .- 1364-5501. ; 19:36, s. 6610-6615
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Tidskriftsartikel (refereegranskat)abstract
- Room temperature ferromagnetic ordering is reported in Ni-tetracyanoethylene (TCNE) thin films fabricated on Au substrates using physical vapor deposition (PVD) under ultra high vacuum conditions. This technique enables the preparation of very clean films without having any kind of contamination from oxygen-containing species, solvents or precursor molecules. Film stoichiometry was obtained from X-ray photoelectron spectroscopy (XPS) measurements. XPS derived stoichiometry points to a similar to 1 : 2 ratio between Ni and TCNE resulting in Ni(TCNE)(x), x approximate to 2. No evidence of pure Ni metal in the in situ grown films was present in the XPS or the ultraviolet photoelectron spectroscopy (UPS) measurements within the detection limits of the techniques.
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| 13. |
- Björk, Per, et al.
(författare)
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Biomolecular nanowires decorated by organic electronic polymers
- 2010
-
Ingår i: JOURNAL OF MATERIALS CHEMISTRY. - : Royal Society of Chemistry (RSC). - 0959-9428 .- 1364-5501. ; 20:12, s. 2269-2276
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate the shaping and forming of organic electronic polymers into designer nanostructures using biomacromolecules. In order to create nanowires, nanohelixes and assemblies of these, we coordinate semiconducting or metallic polymers to biomolecular polymers in the form of DNA and misfolded proteins. Optoelectronic and electrochemical devices utilizing these shaped materials are discussed.
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| 14. |
- Brandell, Daniel, et al.
(författare)
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Molecular Dynamics simulation of the LiPF6∙PEO6 structure
- 2005
-
Ingår i: Journal of Materials Chemistry. - : Royal Society of Chemistry (RSC). - 0959-9428 .- 1364-5501. ; 15:14, s. 1422-1428
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Tidskriftsartikel (refereegranskat)abstract
- Molecular dynamics (MD) simulations have been performed for the crystalline LiPF6·PEO6 system at ambient temperature in an effort to model the detail of its atomic-level structure and dynamics. Start coordinates were taken from the neutron powder diffraction analysis of Gadjourova et al., Chem. Mater., 2001, 13, 1282 (ref. ). Polymer-chain conformation, Li+-ion coordination and thermal displacement parameters are compared with experimentally determined values; the differences found are rationalised in terms of differences between the infinite-chain models investigated (both experimental and theoretical) and the finite chain-length material studied.
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| 15. |
- Bäcklund, Fredrik, et al.
(författare)
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Amyloid fibrils as dispersing agents for oligothiophenes: control of photophysical properties through nanoscale templating and flow induced fibril alignment
- 2014
-
Ingår i: Journal of Materials Chemistry. - : Royal Society of Chemistry (RSC). - 1364-5501 .- 0959-9428 .- 2050-7526 .- 2050-7534. ; 2:37, s. 7811-7822
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Tidskriftsartikel (refereegranskat)abstract
- Herein we report that protein fibrils formed from aggregated proteins, so called amyloid fibrils, serve as an excellent dispersing agent for hydrophobic oligothiophenes such as alpha-sexithiophene (6T). Furthermore, the protein fibrils are capable of orienting 6T along the fibril long axis, as demonstrated by flow-aligned linear dichroism spectroscopy and polarized fluorescence microscopy. The materials are prepared by solid state mixing of 6T with a protein capable of self-assembly. This results in a water soluble composite material that upon heating in aqueous acid undergoes self-assembly into protein fibrils non-covalently functionalized with 6T, with a typical diameter of 5-10 nm and lengths in the micrometre range. The resulting aqueous fibril dispersions are a readily available source of oligothiophenes that can be processed from aqueous solvent, and we demonstrate the fabrication of macroscopic structures consisting of aligned 6T functionalized protein fibrils. Due to the fibril induced ordering of 6T these structures exhibit polarized light emission.
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| 16. |
- Börjesson, Karl, 1982, et al.
(författare)
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Photon upconversion facilitated molecular solar energy storage
- 2013
-
Ingår i: Journal of Materials Chemistry. - 1364-5501 .- 0959-9428. ; 1, s. 8521-8524
-
Tidskriftsartikel (refereegranskat)abstract
- Photon upconversion is used to facilitate the production of a solar fuel. This is done by collocating a triplet–triplet annihilation upconversion system in a microfluidic device with a molecular solar thermal energy storage system. Incoherent truncated white light is used to drive the reaction and the green part of the spectrum is upconverted to blue light, which in turn is absorbed by the solar fuel.
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| 17. |
- Carlsson, Daniel O., et al.
(författare)
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Electroactive nanofibrillated cellulose aerogel composites with tunable structural and electrochemical properties
- 2012
-
Ingår i: Journal of Materials Chemistry. - : Royal Society of Chemistry (RSC). - 0959-9428 .- 1364-5501. ; 22:36, s. 19014-19024
-
Tidskriftsartikel (refereegranskat)abstract
- This work presents conductive aerogel composites of nanofibrillated cellulose (NFC) and polypyrrole (PPy) with tunable structural and electrochemical properties. The conductive composites are prepared by chemically polymerizing pyrrole onto TEMPO-oxidized cellulose nanofibers dispersed in water and the various nanostructures are obtained employing different drying methods. Supercritical CO2 drying is shown to generate high porosity aerogel composites with the largest surface area (246 m(2) g(-1)) reported so far for a conducting polymer-paper based material, whereas composites produced by ambient drying attain high density structures with mechanical properties significantly surpassing earlier reported values for cellulose-conducting polymer composites when normalized with respect to the content of reinforcing cellulose (Young's modulus = 0.51 GPa, tensile strength = 10.93 MPa and strain to failure = 2.5%). Electrochemical measurements clearly show that differences in the porosity give rise to dramatic changes in the voltammetric and chronoamperometric behavior of the composites. This indicates that mass transport rate limitations also should be considered, in addition to the presence of a distribution of PPy redox potentials, as an explanation for the shapes of the voltammetric peaks. A specific charge capacity of similar to 220 C g(-1) is obtained for all composites in voltammetric experiments performed at a scan rate of 1 mV s(-1) and this capacity is retained also at scan rates up to 50 mV s(-1) for the high porosity composites. The composites should be applicable as electrodes in structural batteries and as membranes in ion exchange applications requiring exchange membranes of high mechanical integrity or high porosity.
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| 18. |
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| 19. |
- Cong, Jiayan, et al.
(författare)
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Bis(1,1-bis(2-pyridyl)ethane)copper(I/II) as an efficient redox couple for liquid dye-sensitized solar cells
- 2016
-
Ingår i: Journal of Materials Chemistry. - 0959-9428 .- 1364-5501. ; 4:38, s. 14550-14554
-
Tidskriftsartikel (refereegranskat)abstract
- A new redox couple, [Cu(bpye)2]+/2+, has been synthesized, and applied in dye-sensitized solar cells (DSSCs). Overall efficiencies of 9.0% at 1 sun and 9.9% at 0.5 sun were obtained, which are considerably higher than those obtained for cells containing the reference redox couple, [Co(bpy)3]2+/3+. These results represent a record for copper-based complex redox systems in liquid DSSCs. Fast dye regeneration, sluggish recombination loss processes, faster electron self-exchange reactions and suitable redox potentials are the main reasons for the observed increase in efficiency. In particular, the main disadvantage of cobalt complex-based redox couples, charge-transport problems, appears to be resolved by a change to copper complex redox couples. The results make copper complex-based redox couples very promising for further development of highly efficient DSSCs.
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| 20. |
- Dahlstedt, Emma, et al.
(författare)
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Synthesis of tetrathiafulvalenes suitable for self-assembly applications
- 2004
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Ingår i: Journal of Materials Chemistry. - : Royal Society of Chemistry (RSC). - 0959-9428 .- 1364-5501. ; 14:1, s. 81-85
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Tidskriftsartikel (refereegranskat)abstract
- A series of new tetrathiafulvalenes, with double alkylthiol or alkyldisulfide substitution, have been prepared with a synthetic procedure that allows variation of different substituents. The target compounds 6a-e and 15e-i are sparsely soluble in organic solvents, but TTFs 6d and 15g gave a relatively dense packed monolayer upon exposure to gold surfaces.
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| 21. |
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| 22. |
- Davis, Robert J, et al.
(författare)
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Determination of energy level alignment at interfaces of hybrid and organic solar cells under ambient environment
- 2011
-
Ingår i: JOURNAL OF MATERIALS CHEMISTRY. - : Royal Society of Chemistry. - 0959-9428. ; 21:6, s. 1721-1729
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Tidskriftsartikel (refereegranskat)abstract
- Device function in organic electronics is critically governed by the transport of charge across interfaces of dissimilar materials. Accurate measurements of energy level positions in organic electronic devices are therefore necessary for assessing the viability of new materials and optimizing device performance. In contrast to established methods that are used in solution or vacuum environments, here we combine Kelvin probe measurements performed in ambient environments to obtain work function values with photoelectron spectroscopy in air to obtain ionization potential, so that a complete energy level diagram for organic semiconductors can be determined. We apply this new approach to study commonly used electron donor and acceptor materials in organic photovoltaics (OPV), including poly(3-hexylthiophene) (P3HT), [6,6]-phenyl C61 butyric acid methyl ester (PCBM), and ZnO, as well as examine new materials. Band alignments across the entire OPV devices are constructed and compared with actual device performance. The ability to determine interfacial electronic properties in the devices enables us to answer the outstanding question: why previous attempts to make OPV devices using 6,13-bis(triisopropylsilylethynyl) (TIPS)-pentacene as the electron donor were not successful.
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| 23. |
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| 24. |
- Desroches, C, et al.
(författare)
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Synthesis, characterization and optical power limiting behaviour of phenylazo- and 4-nitrophenylazo-tetrahydroxytetrathiacalix[4]arene
- 2001
-
Ingår i: Journal of Materials Chemistry. - 0959-9428 .- 1364-5501. ; 11:12, s. 3014-3017
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Tidskriftsartikel (refereegranskat)abstract
- p-Tetrakis(4-nitrophenylazo) tetrahydroxytetrathiacalix[4] arene and p-tetrakis(phenylazo) tetrahydroxytetrathiacalix[4] arene were prepared and fully characterized using H-1 and C-13 NMR, mass spectroscopy, thermogravimetric analysis and differential scanning calorimetry. The solid-state structure of p-tetrakis(4-nitrophenylazo) tetrahydroxytetrathiacalix[4] arene was investigated by single crystal X-ray diffraction. It crystallized in the triclinic system (space group: P (1) over bar). z-Scan experiments were performed on the p-tetrakis(4-nitrophenylazo) tetrahydroxytetrathiacalix[ 4] arene showing non linear absorption due to two photon absorption with a TPA cross-section of about 50 x 10(-50) cm(4) s per photon. Optical power limiting measurements on the p-tetrakis( phenylazo) tetrahydroxytetrathiacalix[ 4] arene at 532 nm (48% linear transmission) was found to limit the energy to similar to9 muJ.
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| 25. |
- Dezelah, Charles L., et al.
(författare)
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A low valent metalorganic precursor for the growth of tungsten nitride thin films by atomic layer deposition
- 2007
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Ingår i: Journal of Materials Chemistry. - : Royal Society of Chemistry (RSC). - 0959-9428 .- 1364-5501. ; 17:11, s. 1109-1116
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Tidskriftsartikel (refereegranskat)abstract
- The atomic layer deposition growth of tungsten nitride films was demonstrated using the precursors W-2(NMe2)(6) and ammonia with substrate temperatures between 150 and 250 degrees C. At 180 degrees C, surface saturative growth was achieved with W-2(NMe2)(6) pulse lengths of >= 2.0 s. The growth rates were between 0.74 and 0.81 angstrom cycle(-1) at substrate temperatures between 180 and 210 degrees C. Growth rates of 0.57 and 0.96 angstrom cycle(-1) were observed at 150 and 220 degrees C, respectively. In a series of films deposited at 180 degrees C, the film thicknesses varied linearly with the number of deposition cycles. Films grown at 180 and 210 degrees C exhibited resistivity values between 810 and 4600 mu Omega cm. Time-of-flight elastic recoil detection analysis on tungsten nitride films containing a protective AlN overlayer demonstrated slightly nitrogen-rich films relative to W2N, with compositions of W1.0N0.82C0.13O0.26H0.33 at 150 degrees C, W1.0N0.74C0.20O0.33H0.28 at 180 degrees C, and W1.0N0.82C0.33O0.18H0.23 at 210 degrees C. In the absence of an AlN overlayer, the oxygen and hydrogen levels were much higher, suggesting that the films degrade in the presence of ambient atmosphere. The as-deposited films were amorphous. Amorphous films containing a protective AlN overlayer were annealed to 600 - 800 degrees C under a nitrogen atmosphere. X-Ray diffraction patterns suggested that crystallization does not occur at or below 800 degrees C. Similar annealing of films that did not contain the AlN overlayer afforded X-ray diffraction patterns that were consistent with orthorhombic WO3. Atomic force microscopy showed root-mean-square surface roughnesses of 0.9, 0.8, and 0.7 nm for films deposited at 150, 180, and 210 degrees C, respectively.
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| 26. |
- Ensling, David, et al.
(författare)
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A comparative XPS surface study of Li2FeSiO4/C cycled with LiTFSI- and LiPF6-based electrolytes
- 2009
-
Ingår i: Journal of Materials Chemistry. - : Royal Society of Chemistry (RSC). - 0959-9428 .- 1364-5501. ; 19, s. 82-88
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Tidskriftsartikel (refereegranskat)abstract
- X-Ray photoelectron spectroscopy (XPS) has been used to characterise the surfaces of carbon-coated Li2FeSiO4 cathodes extracted from Li-ion batteries in both a charged and discharged state. 1 M lithium bis(trifluoromethylsulfonyl)imide (LiTFSI) and lithium hexafluorophosphate (LiPF6) based electrolytes were used with ethylene carbonate (EC) and diethyl carbonate (DEC) as organic solvents. The LiTFSI-based electrolyte exhibited high salt stability and no significant formation of LiF. However, solvent reaction products from EC were found together with lithium carbonate. A LiPF6-based electrolyte, on the other hand, showed inferior salt stability with LixPFy, LixPOyFz and LiF species formed on the surface. Solvent reaction products together with lithium carbonate were also found. There are also indications that Li2FeSiO4 is degraded by the HF formed in the electrolyte by the hydrolysis of LiPF6. A better understanding of the surface chemistry of carbon-coated Li2FeSiO4 after the first cycles in a Li-ion battery has thus been achieved, thereby facilitating the optimisation of Li-ion batteries based on this potentially cheap and electrochemically most promising cathode material giving excellent capacity retention: <3% drop over 120 cycles.
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| 27. |
- Eriksson, Kristofer, et al.
(författare)
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Manufacturing of Anisotropic Particles by Site Specific Oxidation of Thiols
- 2012
-
Ingår i: Journal of Materials Chemistry. - 0959-9428 .- 1364-5501. ; 22:16, s. 7681-7683
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Tidskriftsartikel (refereegranskat)abstract
- A novel method for the manufacturing of functional anisotropic particles based on an inexpensive and straightforward electrochemical approach is presented. The method enables large-scale manufacturing of anisotropic particles as well as fabrication of multifunctional beads which may be used in the design of barcodes for multiplex diagnostics.
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| 28. |
- Eriksson, Kristofer, et al.
(författare)
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Manufacturing of anisotropic particles by site specific oxidation of thiols
- 2012
-
Ingår i: Journal of Materials Chemistry. - : Royal Society of Chemistry (RSC). - 0959-9428 .- 1364-5501. ; 22:16, s. 7681-7683
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Tidskriftsartikel (refereegranskat)abstract
- A novel method for the manufacturing of functional anisotropic particles based on an inexpensive and straightforward electrochemical approach is presented. The method enables large-scale manufacturing of anisotropic particles as well as fabrication of multifunctional beads which may be used in the design of barcodes for multiplex diagnostics.
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| 29. |
- Every, Hayley A, et al.
(författare)
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Room temperature fast-ion conduction in imidazolium halide salts
- 2001
-
Ingår i: Journal of Materials Chemistry Articles. - : Royal Society of Chemistry (RSC). - 0959-9428 .- 1364-5501. ; 11:3031-6
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Tidskriftsartikel (refereegranskat)abstract
- Fast-ion conduction has been observed in the iodide and bromide salts of 1-methyl-3-ethylimidazolium at ambient temperatures. The melting point of these two compounds is above 350 K and even at 273 K the ionic conductivity in the solid-state is greater than 10–3S cm–1. Cation diffusion coefficients have been measured using fringe field gradient and/or pulse field gradient 1H NMR techniques, which indicated cation diffusion coefficients of the order of 10–10 m2 s–1 in the solid-state. Remarkably, these values are up to an order of magnitude higher than the cation diffusion coefficient in the supercooled liquid at 293 K. The activation energy for diffusion in the solid-state is extremely small, as is typical of solid-state fast-ion conductors and indicates a change in transport mechanism from the melt to the crystal. The inability to detect an 127I signal together with the modelling of the conductivity using the Nernst–Einstein equation suggests that the solid-state conduction is primarily due to cation diffusion. The solid-state fast-ion conduction is most likely related to vacancy diffusion along the cation layers in the crystal. The temperature dependence of the NMR signal intensity indicates that the number of mobile species is increasing with increasing temperature with an activation energy of approximately 20–30 kJ mol–1.
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| 30. |
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| 31. |
- Galati, R., et al.
(författare)
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The structure of superconducting RbOs2O6 between 2 K and 300 K
- 2007
-
Ingår i: Journal of Materials Chemistry. - : Royal Society of Chemistry (RSC). ; 17:2, s. 160-163
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Tidskriftsartikel (refereegranskat)abstract
- The structure of RbOs2O6 can be described fully in the Fd (3) over barm space group between 2 and 298 K and large thermal displacement factors associated with the Rb ion are probably typical of this structure type and the site occupied.
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| 32. |
- Gao, Chuanbo, 1981-
(författare)
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Molecular design of AEC tri-block anionic surfactant towards rational synthesis of targeted thick-walled mesoporous silica
- 2009
-
Ingår i: Journal of Materials Chemistry. - United Kingdom : The Royal Society of Chemistry. - 0959-9428 .- 1364-5501. ; 19, s. 3404-3411
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Tidskriftsartikel (refereegranskat)abstract
- Here we report a new synthesis strategy to synthesize thick-walled two dimensional hexagonal mesoporous silicas, using tri-block surfactant fatty alcohol ether carboxylate [AEC: CnH2n+1O(CH2CH2O)mCH2COONa] with two different hydrophilic head groups of (EO)x-block and anionic carboxylate. The unique formation of double-layer silica wall arose from two types of hydrophilic head groups via the silica source condensation led to an obvious increase in the wall thickness. The successful carbon replication proved the existence of micropores formed by imbedded (EO)x-block and electrostatic bonding of carboxylate head group and organic group of co-structuredirecting agent. The template-free mesoporous silica showed a high hydrothermal stability due to the thick wall.
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| 33. |
- Gao, Chuanbo, 1981-
(författare)
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Molecular design of the surfactant and the co-structure-directing agent (CSDA) toward rational synthesis of targeted anionic surfactant templatedmesoporous silica
- 2007
-
Ingår i: Journal of Materials Chemistry. - United Kingdom : The Royal Society of Chemistry. - 0959-9428 .- 1364-5501. ; 17, s. 3591-3602
-
Tidskriftsartikel (refereegranskat)abstract
- The formation of anionic surfactant templated mesoporous silica (AMS) is investigated from the perspective of the geometrical molecular design of the surfactant and the co-structure-directing agent (CSDA) toward the rational synthesis of the targeted mesostructure. Increasing the geometrical size of two types of head group of the anionic surfactant in the order (i) sulfonate, sulfate and phosphate, and (ii) carboxylate, N-acylalanate/N-acylglycinate and N-acylglutamate, resulted in the mesophase changing from a disordered or lamellar phase to two-dimensional (2D) hexagonal (p6mm) and three-dimensional (3D) cage-type (hexagonal and a modulated cubic phase) with increasing order of the organic/inorganic interface curvature. A change in the chain length of the surfactant also led to different surfactant packing and mesophase interfacial curvatures, and resulted in a change in mesophase from a modulated cage-type mesophase to cubic Fd-3m, cubic Pm-3n and a disordered cage-type mesophase. The geometrical change in the CSDA resulted in an increasing micellar curvature in the order: aminopropyl , N-methylaminopropyl, N,N-dimethylaminopropyl trimethoxysilane, which led to a change of mesophase from bicontinuous cubic Pn-3m to 2D-hexagonal p6mm. An increase in the CSDA/surfactant ratio in the synthesis gave rise to the mesophase change from a disordered cage-type mesophase to cubic Fm-3m or from lamellar to 2D-hexagonal p6mm, and elemental analysis results showed that the mesoporous silicas have an increased loading of organic moieties using the CSDA method.
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| 34. |
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| 35. |
- Goncalves, Gil, et al.
(författare)
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Graphene oxide modified with PMMA via ATRP as a reinforcement filler
- 2010
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Ingår i: Journal of Materials Chemistry. - : Royal Society of Chemistry (RSC). - 0959-9428 .- 1364-5501. ; 40:44, s. 9927-9934
-
Tidskriftsartikel (refereegranskat)abstract
- Graphene is a two-dimensional new allotrope of carbon, which is stimulating great curiosity due to its superior mechanical, electrical, thermal and optical properties. Particularly attractive is the availability of bulk quantities of graphene (G) which can be easily processed by chemical exfoliation, yielding graphene oxide (GO). The resultant oxygenated graphene sheets covered with hydroxyl, epoxy and carboxyl groups offer tremendous opportunities for further functionalization opening plenty of opportunities for the preparation of advanced composite materials. In this work poly(methyl methacrylate) (PMMA) chains have been grafted from the GO surface via atom transfer radical polymerization (ATRP), yielding a nanocomposite which was soluble in chloroform. The surface of the PMMA grafted GO (GPMMA) was characterized by AFM, HRTEM, Raman, FTIR and contact angle. The interest of these novel nanocomposites lies in their potential to be homogenously dispersed in polymeric dense matrices and to promote good interfacial adhesion, of particular relevance in stress transfer to the fillers. PMMA composite films were prepared using different percentages of GPMMA and pristine GO. Mechanical analysis of the resulting films showed that loadings as low as 1% (w/w) of GPMMA are effective reinforcing agents, yielding tougher films than pure PMMA films and even than composite films of PMMA prepared with GO. In fact, addition of 1% (w/w) of GPMMA fillers led to a significant improvement of the elongation at break, yielding a much more ductile and therefore tougher material. Thermal analysis showed an increase of the thermal stability properties of these films providing evidence that strong interfacial interactions between PMMA and GPMMA are achieved. In addition, AFM analysis, in friction force mode, is demonstrated to be an effective tool to analyse the surface filler distribution on polymer matrices
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| 36. |
- Grins, Jekabs, et al.
(författare)
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Phases in the ZrxTa1-x(O,N)y System, Formed by Ammonolyses of Zr-Ta Gels. Preparation of Baddeleyite Type Solid Solution Phase ZrxTa1-xO1+xN1-x, 0≤x≤1
- 1994
-
Ingår i: Journal of Materials Chemistry. - 0959-9428 .- 1364-5501. ; 4, s. 1293-1301
-
Tidskriftsartikel (refereegranskat)abstract
- Phase formation in the system ZrxTa1–x(O,N)y has been studied by ammonolysis of Zr-Ta gels, prepared by the sol–gel technique, at temperatures between 700 and 1000 °C. The starting gels and observed phases were characterised by X-ray powder diffraction (XRPD), scanning and transmission electron microscopy (SEM and TEM) and thermogravimetric (TG) analysis. Oxynitride phases of compositions ZrxTa1–xO1 +xN1–x, 0≤x≤1, with the baddeleyite-type structure, were prepared at 800 °C. The unit-cell volume increased linearly from 127.8 Å3 for TaON (x= 0) to 140.9 Å3 for ZrO2(x= 1). The structure was verified for the composition Zr0.4Ta0.6O1.6N0.4(x= 0.4) by a Rietveld refinement (RF= 3.5%) using Cu-Kα1, XRPD data. An orthorhombic oxynitride phase was observed in preparations at 700 °C for 0.26 ≤x≤ 0.90 in ZrxTa1–xO1+xN1–x. Unit-cell parameters and powder X-ray reflection intensities agree with an orthorhombic ZrO2 type structure. According to X-ray data, a cubic solid solution phase with a fluorite related subcell is present in materials prepared at 900 °C for 0.26≤x≤ 0.68. However, electron microdiffraction patterns suggest a metrically monoclinic unit cell with a = 6.1 Å, b= 14.1 Å, c= 7.1 Å and β= 125°. The Ta3N5, type of structure was found to incorporate up to ca. 18 atom% Zr at 900 and 1000 °C.
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| 37. |
- Grins, J., et al.
(författare)
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Synthesis and magnetic susceptibility of the rutile phase MnTaO4
- 2000
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Ingår i: Journal of Materials Chemistry. - : Royal Society of Chemistry (RSC). - 0959-9428 .- 1364-5501. ; 10:9, s. 2197-2200
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Tidskriftsartikel (refereegranskat)abstract
- The Mn3+-containing oxide MnTaO4 was synthesized at 1050 degrees C and 2 kbar partial oxygen gas pressure. It has a rutile-type structure, space group P4(2)/mnm, with a = 4.7189(3), c = 2.9843(3) Angstrom, and a statistical distribution of Mn/Ta. The structure was refined by the Rietveld method using both X-ray and neutron powder diffraction. The refinements, and energy-dispersive X-ray microanalysis, indicate that the phase may contain a small amount of Mn4+ and have the actual composition Mn1.08(2)Ta0.92(2)O4. The magnetic susceptibility shows a maximum at 16 K and Curie-Weiss behavior at higher temperatures, with mu(eff) = 5.11(4) mu(B) per Mn atom. The susceptibility is consistent with spin-glass behavior: (i) the temperature at the susceptibility maximum is frequency-dependent and (ii) field cooled and zero-field cooled susceptibility curves differ below the maximum. Neutron powder diffraction data collected at 10 K does not show any sharp magnetic reflections, but a very broad reflection, with a full width at half maximum height of 7 degrees, at a position corresponding to the 100 reflection is seen.
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| 38. |
- Grins, Jekabs, et al.
(författare)
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Synthesis and structural characterisation of MnWN2 prepared by ammonolysis of MnWO4
- 1995
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Ingår i: Journal of Materials Chemistry. - 0959-9428 .- 1364-5501. ; 5, s. 571-575
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Tidskriftsartikel (refereegranskat)abstract
- A new ternary transition-metal nitride, the composition of which is close to MnWN2, has been synthesized by ammonolysis of X-ray amorphous MnWO4 at 800 degrees C. The Guinier-Hagg powder pattern could be indexed with a hexagonal cell with a = 2.9213(3) Angstrom and c = 10.957(2) Angstrom. Although no superstructure reflections could be observed in the X-ray powder diffraction pattern, such reflections were revealed by electron diffraction. In most of the crystallites investigated, the relationship between supercell and the hexagonal (sub)cell was found to be a(super) = root 3a(hex). A Rietveld structure determination, based on space group P6(3)me (no. 186), showed that the metal atoms were approximately close-packed in an ABAC... sequence with Mn at site 2(a) and W at site 2(d), The lowest R(F) value (10%) was obtained for an ordered structure model with the Mn and N atoms occupying 2(a) and the W and N at sites 2(b). Measurements of the magnetic susceptibility, and of the electrical resistivity, indicated a metallic behaviour of MnWN2
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| 39. |
- Gromov, Andrei, 1959, et al.
(författare)
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Covalent Amino functionalisation of single walled carbon nanotubes
- 2005
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Ingår i: J. Materials Chem. - : Royal Society of Chemistry (RSC). - 0959-9428 .- 1364-5501. ; 15, s. 3334-3339
-
Tidskriftsartikel (refereegranskat)abstract
- Chemical transformation of single-wall carbon nanotubes (SWNT), edge-terminated with carboxylic groups, to SWNT species with amino groups directly attached to the tube open ends has been performed. Different synthetic approaches have been investigated. The reaction products were characterised by FTIR, Raman spectroscopy, XPS and SEM.
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| 40. |
- Gunawidjaja, Philips N., et al.
(författare)
-
Quantifying apatite formation and cation leaching from mesoporous bioactive glasses in vitro : a SEM, solid-state NMR and powder XRD study
- 2012
-
Ingår i: Journal of Materials Chemistry. - : Royal Society of Chemistry (RSC). - 0959-9428 .- 1364-5501. ; 22:15, s. 7214-7223
-
Tidskriftsartikel (refereegranskat)abstract
- By employing solid-state nuclear magnetic resonance (NMR) spectroscopy, powder X-ray diffraction (PXRD), and scanning electron microscopy coupled with energy-dispersive X-ray (EDX) spectroscopy, we compare the biomimetic growth of calcium hydroxyapatite (HA) from an ordered mesoporous bioactive glass (MBG) in simulated body fluid (SBF) and buffered water solutions. For the latter medium, we also examine the effects of using two different MBG concentrations. We evaluate the predicting powers of PXRD and P-31 NMR for directly quantifying the relative amounts of biomimetic amorphous calcium phosphate (ACP) and HA: we observe a very good agreement between the two analytical techniques. Thanks to their mesoporous channel system, fluids readily penetrate throughout sub-mm sized MBG grains, as evidenced by EDX. The latter revealed distinct element-mappings across the material after its exposure to SBF compared to water. Under our in vitro conditions involving relatively high MBG-loadings in the solutions, the HA formation reduces in SBF relative to buffered water, particularly for increasing MBG concentration. These features stem from a high [Ca2+]/[PO43-] ratio resulting in the fluid medium, which retards the HA crystallization by inducing a rapid ACP precipitation and an accompanying depletion of phosphate ions in the solution. This has bearings on the design of bioactivity comparisons of bioglasses exhibiting significantly different cation compositions.
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| 41. |
- Hagberg, Daniel, 1977-, et al.
(författare)
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Symmetric and unsymmetric donor functionalization : Comparing structural and spectral benefits of chromophores for dye-sensitized solar cells
- 2009
-
Ingår i: Journal of Materials Chemistry. - : Royal Society of Chemistry (RSC). - 0959-9428 .- 1364-5501. ; 19:39, s. 7232-7238
-
Tidskriftsartikel (refereegranskat)abstract
- A series of organic chromophores have been synthesized in order to investigate the benefits of structural versus spectral properties as well as the absorption properties and solar cell performance with unsymmetrically introduced substituents in the chromophore. Exceptionally high open-circuit voltage, Voc, was found for the symmetrical structurally benefited dye, which also gave the best overall solar cell performance.
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| 42. |
- Han, Lu, et al.
(författare)
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Carboxylic group functionalized ordered mesoporous silicas
- 2011
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Ingår i: Journal of Materials Chemistry. - : Royal Society of Chemistry (RSC). - 0959-9428 .- 1364-5501. ; 21:30, s. 11033-11039
-
Tidskriftsartikel (refereegranskat)abstract
- Many research efforts have focused on the synthesis of organic and inorganic hybrid ordered mesoporous silicas (MSs) with functionalization of the exterior and/or interior surfaces aiming for applications in separation, adsorption, catalysis, drug delivery, and nanotechnology. Among the organic groups, the carboxylic group is a particularly useful reactive group for many applications. This article provides a brief overview of the carboxylic group functionalized MSs and the recent progress in synthetic strategies and applications have been reviewed.
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| 43. |
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| 44. |
- Hao, Fuying, et al.
(författare)
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Design, crystal structures and enhanced frequency-upconverted lasing efficiencies of a new series of dyes from hybrid of inorganic polymers and organic chromophores
- 2009
-
Ingår i: Journal of Materials Chemistry. - : RSC Publishing. - 0959-9428 .- 1364-5501. ; 19:48, s. 9163-9169
-
Tidskriftsartikel (refereegranskat)abstract
- A new series of hybrid dyes, trans-4-(4′-N,N-dialkylaminostyryl)-N-methyl pyridinium [Cd(SCN)3−]n [alkyl = Me(1), Et(2), Pr(3) and n–Bu(4)] have been successfully synthesized from hybrids of inorganic polymers and organic chromophores. The structures of four new hybrid dyes were characterized by single-crystal X-ray diffraction first. The particular features of the hybrid dyes are (1) the inorganic anions form isolated polymeric one-dimensional zig-zag chains of [Cd(SCN)3−]n with an extended π-conjugation system within the polymeric –[M–S–C≡N]–M… chain and high polarizabilities; and (2) the organic cationic chromophores determine their optical properties. Experimental results revealed that the TPA cross-section values and overall energy conversion efficiencies of hybrid dyes with different alkyl pendant groups have obviously increased from 1 to 4, and in particular, have been substantially enhanced compared to their corresponding iodide analogues 1′–4′. Therefore, we speculate that such increases are attributable to arrangements of infinite anionic [Cd(SCN)3−]n chains and synergic effects with chromophore cations.
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| 45. |
- Hector, A. L., et al.
(författare)
-
An unusual magnetic structure in Sr2FeO3F and magnetic structures of K2NiF4-type iron(III) oxides and oxide halides, including the cobalt substituted series Sr2Fe 1-xCoxO3Cl
- 2005
-
Ingår i: Journal of Materials Chemistry. - : Royal Society of Chemistry (RSC). - 1364-5501 .- 0959-9428. ; 15:30, s. 3093-3103
-
Tidskriftsartikel (refereegranskat)abstract
- An unusual k = [1/2 1/2 1/2] magnetic structure is reported in Sr 2FeO3F at low temperature. The magnetic structures of LaBaFeO4, LaSrFeO4, LaCaFeO4, Ca 2FeO3Cl, Ca2FeO3Br, Sr 2FeO3F, Sr2FeO3Cl, Sr 2FeO3Br and solid solutions in the series Sr 2Fe1-xCoxO3Cl have been examined and only Sr2FeO3F exhibits this structure. The La 2CuO4-type spin arrangement dominates in all these phases, with antiferromagnetic ordering in the xy planes. The k = [1/2 1/2 1/2] magnetic phase in Sr2FeO3F occurs below 100 K and requires La2CuO4-type stacking across the SrO layers and La2NiO4-type stacking across the SrF layers. It has been possible to show that this phase grows in domains which have purely La 2CuO4-type stacking at higher temperatures. In the Sr 2Fe1-xCoxO3Cl series the La 2CuO4-type magnetic structure in Sr2FeO 3Cl and the La2NiO4-type structure in Sr 2CoO3Cl coexist and structural and magnetic behaviour indicate phase segregation into cobalt- and iron-rich regions.
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| 46. |
- Herland, Anna, et al.
(författare)
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Decoration of amyloid fibrils with luminescent conjugated polymers
- 2008
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Ingår i: Journal of Materials Chemistry. - : Royal Society of Chemistry (RSC). - 0959-9428 .- 1364-5501. ; 18:1, s. 126-132
-
Tidskriftsartikel (refereegranskat)abstract
- In this work we report the coating of a biological template with a polar, but uncharged, luminescent conjugated polymer, soluble in organic solvents but not in water, to produce a nanowire. Amyloid fibrils from bovine insulin were decorated with an alternating polyfluorene derivative. Decorated fibrils were partially aligned on hydrophobic surfaces as separate and bundled fibrils, by means of molecular combing. The single molecule spectroscopy technique utilizing excitation by rotating linearly polarized light and fluorescence detection through a rotating polarizer showed a high degree of anisotropy of the polymer chains on the individual fibrils. The high degree of polarization indicated highly oriented polymer chains with the preferential orientation of the polymer backbone along the fibrils. The anisotropy ratios are comparable with those of well-oriented polymer chains in films. © The Royal Society of Chemistry.
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| 47. |
- Hotta, Y, et al.
(författare)
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Coated polystyrene particles as templates for ordered macroporous silica structures with controlled wall thickness
- 2003
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Ingår i: Journal of Materials Chemistry. - 0959-9428 .- 1364-5501. ; 13, s. 496-501
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Tidskriftsartikel (refereegranskat)abstract
- Polystyrene (PS) colloidal particles have been used as templates to produce ordered macroporous silica structures. The silica films were deposited from ethanol solution containing acidic water and tetraethyl orthosilicate. The silica-coated PS spheres were characterized using transmission electron microscopy, and the film thickness determined by scanning electron microscopy and calculated from the relative weight of silica remaining after calcination. We found that the thickness of the silica film increased rapidly with time and reached a maximum that varied from 40 to 15 nm at pH 1.5 and 3, respectively. The data could be fitted to a simple first-order equation and the reaction rate and maximum thickness were related to the hydrolysis and condensation rate, respectively. Ordered macroporous structures were formed by centrifuging silica-coated PS spheres. Calcination of the close-packed spheres yielded a continuous silica matrix consisting of a three-dimensional well-ordered network of monodisperse pores
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| 48. |
- Hu, Guangzhi, et al.
(författare)
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Self-assembled palladium nanocrystals on helical carbon nanofibers as enhanced electrocatalysts for electro-oxidation of small molecules
- 2012
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Ingår i: Journal of Materials Chemistry. - : Royal Society of Chemistry (RSC). - 0959-9428 .- 1364-5501. ; 22:17, s. 8541-8548
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Tidskriftsartikel (refereegranskat)abstract
- We present a novel approach to prepare helical carbon nanofibers homogeneously functionalized with single crystal palladium nanoparticles via a phase-transfer method. The materials were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDX), thermogravimetric analysis (TGA) and electrochemical measurements. We find that homogeneous and small single-crystal Pd nanoparticles can be easily functionalized with phenyl mercaptan, transferred into the toluene phase from the dimethyl sulfoxide (DMSO) phase and then non-covalently self-assembled onto the surface of helical carbon nanofibers with a very good dispersion and homogeneous diameters of 4.5 +/- 0.6 nm. The palladium-helical carbon nanofiber composite exhibits significantly higher electrochemical active area and electrocatalytic activity towards the electrooxidation of formic acid, ethanol and methanol than the commercial electrocatalyst Pd/Vulcan XC-72. Our results show that the prepared material can be potentially used as an advanced nano-electrocatalyst in a direct alkaline fuel cell system.
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| 49. |
- Huang, Z. L., et al.
(författare)
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Novel heterocycle-based organic molecules with two-photon induced blue fluorescent emission
- 2003
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Ingår i: Journal of Materials Chemistry. - : Royal Society of Chemistry (RSC). - 0959-9428 .- 1364-5501. ; 13:4, s. 708-711
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Tidskriftsartikel (refereegranskat)abstract
- Two-photon absorption and two-photon induced blue emission characteristics of a series of heterocycle-based organic molecules are investigated experimentally and by quantum-chemical computations. The molecules consist of a typical A-pi-A' structure, where heterocycle, styryl and formyl groups are employed as A, pi-conjugated and A' moieties, respectively. Experimental results indicate that significant enhancements in the blue emission efficiency and two-photon absorption cross-sections can be achieved by replacing S and O atoms with an N atom in the heterocycle acceptor moiety, which is also supported by the quantum-chemical computations. Additionally, larger two-photon absorption cross-sections can be obtained by choosing appropriate solvents, as indicated by the computations.
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| 50. |
- Hörlin, Tom, et al.
(författare)
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Extended defect structures in zinc oxide doped with iron and indium
- 1998
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Ingår i: Journal of Materials Chemistry. - 0959-9428 .- 1364-5501. ; 8, s. 2465-2473
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Tidskriftsartikel (refereegranskat)abstract
- The effects of iron- and indium oxide doping on the structure: and magnetic susceptibility of ZnO have been studied. The nominal compositions were InxFe2-xO3(ZnO)n with 0 less than or equal to x less than or equal to 1 and n= 23, 48 and 98. Magnetic measurements showed the iron-doped samples to be paramagnetic, with a behaviour indicating antiferromagnetic coupling between the iron-ions. HREM studies showed that indium and iron are incorporated as layer defects of two kinds. One type forms cubic close packed (ccp) planes perpendicular to the c axis, and the other appears as-corrugated layers inserted between the former. The folds in the corrugated layers consist of alternating (114) and (11 (4) over bar) planes. Analytical transmission electron microscopy studies revealed that indium prefers the ccp layers, whereas iron can be found in both types of defects. Structural models based upon the experimental results are presented.
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