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Author De Gryse, O.; Clauws, P.; Vanhellemont, J.; Lebedev, O.; van Landuyt, J.; Simoen, E.; Claeys, C.
Title Chemical and structural characterization of oxide precipitates in heavily boron doped silicon by infrared spectroscopy and transmission electron microscopy Type P1 Proceeding
Year 2002 Publication Abbreviated Journal
Volume Issue Pages 183-194
Keywords P1 Proceeding; Electron microscopy for materials research (EMAT)
Abstract (up) Infrared absorption spectra of oxygen precipitates in boron doped silicon with a boron concentration between 10(17) and 10(19) cm(-3) are analyzed, applying the spectral function theory of the composite precipitates. The aspect ratio of the platelet precipitates has been determined by transmission electron microscopy measurements. Our analysis shows that in samples with moderate doping levels (<10(18) B cm(-3)) SiOgamma precipitates are formed with stoichiometry as in the lightly doped case. In the heavily (>10(18) cm(-3)) boron doped samples, however, the measured spectra of the precipitates are consistent with a mixture of SiO2 and B2O3. with a volume fraction of B2O3 as high as 0.41 in the most heavily doped case.
Address
Corporate Author Thesis
Publisher Place of Publication S.l. Editor
Language Wos Publication Date 0000-00-00
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1-56677-344-X ISBN Additional Links UA library record; WoS full record;
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ lucian @ c:irua:94950 Serial 344
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Author de Gryse, O.; Clauws, P.; Vanhellemont, J.; Lebedev, O.I.; van Landuyt, J.; Simoen, E.; Claeys, C.
Title Characterization of oxide precipitates in heavily B-doped silicon by infrared spectroscopy Type A1 Journal article
Year 2004 Publication Journal of the electrochemical society Abbreviated Journal J Electrochem Soc
Volume 151 Issue 9 Pages G598-G605
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract (up) Infrared absorption spectra of oxygen precipitates in boron-doped silicon with a boron concentration between 10(17) and 10(19) cm(-3) are analyzed, applying the spectral function representation of composite materials. The aspect ratio of the platelet precipitates is determined by transmission electron microscopy measurements. The analysis shows that in samples with moderate doping levels (<10(18) B cm(-3)) SiOγ precipitates are formed with the same composition as in the lightly doped case. In the heavily boron-doped (>10(18) cm(-3)) samples, however, the measured spectra of the precipitates are consistent with a mixture of SiO2 and B2O3, with a volume fraction of B2O3 as high as 0.41 in the most heavily doped case. (C) 2004 The Electrochemical Society.
Address
Corporate Author Thesis
Publisher Place of Publication New York, N.Y. Editor
Language Wos 000223622000072 Publication Date 2004-08-30
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0013-4651; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.259 Times cited 13 Open Access
Notes Fwo; Iuap P5/01 Approved Most recent IF: 3.259; 2004 IF: 2.356
Call Number UA @ lucian @ c:irua:103760 Serial 330
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Author de Gryse, O.; Clauws, P.; Lebedev, O.; van Landuyt, J.; Vanhellemont, J.; Claeys, C.; Simoen, E.
Title Chemical and structural characterization of oxygen precipitates in silicon by infrared spectroscopy and TEM Type A1 Journal article
Year 2001 Publication Physica: B : condensed matter T2 – 21st International Conference on Defects in Semiconductors, JUL 16-20, 2001, GIESSEN, GERMANY Abbreviated Journal Physica B
Volume 308 Issue Pages 294-297
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract (up) Infrared absorption spectra of polyhedral and platelet oxygen precipitates are analyzed using a modified Day-Thorpe approach (J. Phys.: Condens. Matter 11 (1999) 2551). The aspect ratio has been determined by TEM measurements. The reduced spectral function and the stoichiometry are extracted from the absorption spectra and the concentration of precipitated interstitial oxygen. One set of spectra reveal a Frohlich frequency around 1100 cm(-1) and another around 1110-1120 cm(-1). It is shown that the shift in the Frohlich frequency is not due to a different stoichiometry, but due to the detailed structure in the reduced spectral function. The oxygen precipitates consist of SiO. with gammaapproximate to1.1-1.2+/-0.1. (C) 2001 Elsevier Science B.V. All rights reserved.
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Corporate Author Thesis
Publisher Elsevier science bv Place of Publication Amsterdam Editor
Language Wos 000173660100073 Publication Date 2002-10-15
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0921-4526; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.386 Times cited 3 Open Access
Notes Approved Most recent IF: 1.386; 2001 IF: 0.663
Call Number UA @ lucian @ c:irua:103389 Serial 345
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Author Gryse, O.D.; Clauws, P.; van Landuyt, J.; Lebedev, O.; Claeys, C.; Simoen, E.; Vanhellemont, J.
Title Oxide phase determination in silicon using infrared spectroscopy and transmission electron microscopy techniques Type A1 Journal article
Year 2002 Publication Journal of applied physics Abbreviated Journal J Appl Phys
Volume 91 Issue 4 Pages 2493-2498
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract (up) Infrared absorption spectra of polyhedral and platelet oxygen precipitates in silicon are analyzed using a modified Day-Thorpe approach [J. Phys.: Condens. Matter 11, 2551 (1999)]. The aspect ratio of the precipitates is determined by transmission electron microscopy analysis. The reduced spectral function and the stoichiometry of the precipitate are extracted from the absorption spectra and the amount of precipitated interstitial oxygen. The experimental absorption spectra can be divided in a set with a Frohlich frequency of around 1100 cm(-1) and in a set with a Frohlich frequency between 1110 and 1120 cm(-1). It is shown that the shift in the Frohlich frequency is not due to a differing stoichiometry, but to the detailed structure of the reduced spectral function. Inverse modeling of the spectra suggests that the oxide precipitates consist of substoichiometric SiOgamma with gamma=1.17+/-0.14. (C) 2002 American Institute of Physics.
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Corporate Author Thesis
Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
Language Wos 000173553800114 Publication Date 2002-07-26
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0021-8979; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.068 Times cited 27 Open Access
Notes Approved Most recent IF: 2.068; 2002 IF: 2.281
Call Number UA @ lucian @ c:irua:103372 Serial 2542
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Author Sudheendra, L.; Moshnyaga, V.; Lebedev, O.I.; Gehrke, K.; Belenciuc, A.; Shapoval, O.; Van Tendeloo, G.; Samwer, K.
Title A-site ordering and stripe phases in manganite films Type A1 Journal article
Year 2008 Publication Physica: B : condensed matter T2 – International Conference on Strongly Correlated Electron Systems (SCES, 2007), MAY 13-18, 2007, Houston, TX Abbreviated Journal Physica B
Volume 403 Issue 5-9 Pages 1645-1646
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract (up) Insulating and metallic stripes above and below the Curie temperature, T-C, respectively, were observed by a high-resolution scanning tunneling microscopy (STM) and/or spectroscopy (STS) in A-site ordered and macroscopically strain free epitaxial La0.75Ca0.25MnO3 film grown on MgO substrate. The “insulating” stripes were found to be incommensurable to the lattice and aligned along (110) direction. Metallic stripes were commensurable with periodicity 2a(p)similar to 0.8 nm and aligned parallel to the crystallographic a/b-axis. Formation of these stripes involves competing charge, orbital, and lattice orders and is an outcome of an overlapping of electron wave functions mediated by the local lattice-strain distribution, existed even in A-site ordered film due to the difference in cation radii of La and Ca. (C) 2007 Elsevier B.V. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000254689900330 Publication Date 2007-11-06
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0921-4526; ISBN Additional Links UA library record; WoS full record
Impact Factor 1.386 Times cited Open Access
Notes Approved Most recent IF: 1.386; 2008 IF: 0.822
Call Number UA @ lucian @ c:irua:104031 Serial 26
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Author Lebedev, O.I.; Van Tendeloo, G.; Amelinckx, S.; Leibold, B.; Habermeier, H.U.; Phillipp, F.
Title Structure and magnetotransport properties of La2/3Ca1/3MnO3 thin films prepared by pulsed laser deposition Type P1 Proceeding
Year 1998 Publication Materials Research Society symposium proceedings T2 – Symposium on Advances in Laser Ablation of Materials at the 1998 MRS, Spring Meeting, April 13-16, 1998, San Francisco, Calif. Abbreviated Journal
Volume Issue Pages 219-224
Keywords P1 Proceeding; Electron microscopy for materials research (EMAT)
Abstract (up) La1-xCaxMnO3-delta (LCMO) thin films are grown by pulsed laser deposition on a (100) SrTiO3 substrate at temperatures between 530 degrees C and 890 degrees C. The magnetotransport properties show a high negative magnetoresistance and a shift of the maximum of the R(T) curve as function of temperature. The Curie temperature changes with deposition temperature and film quality in the range of 100-220K. The film quality is characterised by X-ray diffraction and transmission electron microscopy (TEM); film and target compositions were verified by atomic emission spectroscopy. The local structure of the film depends on the growth conditions and substrate temperature. TEM reveals a slight distortion of the film leading to a breakdown of the symmetry from orthorhombic to monoclinic. At the highest growth temperatures, a well defined interface is observed within the LCMO film, parallel to the substrate surface; this interface divides the film into two lamellae with a different microstructure. The lamella close to the substrate is perfectly coherent with the substrate, suggesting that it is strained as a result of the lattice parameter mismatch; the upper lamella shows a typical domain structure with unusual translation interfaces characterised by a displacement vector of the type 1/2[010](m) and 1/2[001](m) when referred ten the monoclinic lattice.
Address
Corporate Author Thesis
Publisher Materials research society Place of Publication Warrendale Editor
Language Wos 000077696000032 Publication Date 2011-04-05
Series Editor Series Title Abbreviated Series Title
Series Volume 526 Series Issue Edition
ISSN 1946-4274; ISBN Additional Links UA library record; WoS full record
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ lucian @ c:irua:95838 Serial 3283
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Author Maignan, A.; Martin, C.; Singh, K.; Simon, C.; Lebedev, O.I.; Turner, S.
Title From spin induced ferroelectricity to dipolar glasses : spinel chromites and mixed delafossites Type A1 Journal article
Year 2012 Publication Journal of solid state chemistry Abbreviated Journal J Solid State Chem
Volume 195 Issue Pages 41-49
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract (up) Magnetoelectric multiferroics showing coupling between polarization and magnetic order are attracting much attention. For instance, they could be used in memory devices. Metal-transition oxides are provided several examples of inorganic magnetoelectric multiferroics. In the present short review, spinel and delafossite chromites are described. For the former, an electric polarization is evidenced in the ferrimagnetic state for ACr2O4 polycrystalline samples (A=Ni, Fe, Co). The presence of a JahnTeller cation such as Ni2+ at the A site is shown to yield larger polarization values. In the delafossites, substitution by V3+ at the Cr or Fe site in CuCrO2 (CuFeO2) suppresses the complex antiferromagnetic structure at the benefit of a spin glass state. The presence of cation disorder, probed by transmission electron microscopy, favors relaxor-like ferroelectricity. The results on the ferroelectricity of ferrimagnets and insulating spin glasses demonstrate that, in this research field, transition-metal oxides are worth to be studied.
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Corporate Author Thesis
Publisher Place of Publication London Editor
Language Wos 000309783600006 Publication Date 2012-02-09
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0022-4596; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.299 Times cited 27 Open Access
Notes Fwo Approved Most recent IF: 2.299; 2012 IF: 2.040
Call Number UA @ lucian @ c:irua:101219 Serial 1286
Permanent link to this record
 
 
Author Afanasov, I.M.; Lebedev, O.I.; Kolozhvary, B.A.; Smirnov, A.V.,; Van Tendeloo, G.
Title Nickel/carbon composite materials based on expanded graphite Type A1 Journal article
Year 2011 Publication New carbon materials Abbreviated Journal
Volume 26 Issue 5 Pages 335-340
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract (up) Monolithic nickel/carbon (Ni/C) composites were prepared from coal tar pitch-impregnated compressed expanded graphite pre-decorated with NiO particles (EGNiO) by pyrolysis at 550 °C and subsequent steam activation at 800 °C. The microstructural arrangement of the Ni-comprising nanoparticles in the composites was investigated using transmission electron microscopy. The specific surface area and porosity of the composites were analyzed by nitrogen adsorption. The catalytic activity of the composites was compared with the material obtained by the conventional H2 treatment of EGNiO using hydrocracking of 2,2,3-trimethylpentane as a model reaction.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000296926500003 Publication Date 2011-11-12
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1872-5805; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited 7 Open Access
Notes Iap Approved Most recent IF: NA
Call Number UA @ lucian @ c:irua:93633 Serial 2340
Permanent link to this record
 
 
Author Li, Y.; Tan, H.; Lebedev, O.; Verbeeck, J.; Biermans, E.; Van Tendeloo, G.; Su, B.-L.
Title Insight into the growth of multiple branched MnOOH nanorods Type A1 Journal article
Year 2010 Publication Crystal growth & design Abbreviated Journal Cryst Growth Des
Volume 10 Issue 7 Pages 2969-2976
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract (up) Multiple branched manganese oxide hydroxide (MnOOH) nanorods prepared by a hydrothermal process were extensively studied by transmission electron microscopy (TEM). A model of the branch formation is proposed together with a study of the interface structure. The sword-like tip plays a crucial role for the nanorods to form different shapes. Importantly, the branching occurs at an angle of around either 57 degrees or 123 degrees. Specifically, a (111) twin plane can only be formed at the interface with a 123 degrees angle. The interfaces formed with a 57 degrees angle usually contain edge dislocations. Electron energy loss spectroscopy (EELS) demonstrates that the whole crystal has a uniform chemical composition. Interestingly, an epitaxial growth of Mn3O4 at the radial surface was also observed under electron beam irradiation; this is because of the rough purification of the products. The proposed mechanism is expected to shed light on the branched/dendrite nanostructure growth and to provide opportunities for further novel nanomaterial structure growth and design.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000279422700027 Publication Date 2010-06-08
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1528-7483;1528-7505; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.055 Times cited 41 Open Access
Notes Fwo; Esteem 026019 Approved Most recent IF: 4.055; 2010 IF: 4.390
Call Number UA @ lucian @ c:irua:83886UA @ admin @ c:irua:83886 Serial 1672
Permanent link to this record
 
 
Author Krsmanovic, R.; Morozov, V.A.; Lebedev, O.I.; Polizzi, S.; Speghini, A.; Bettinelli, M.; Van Tendeloo, G.
Title Structural and luminescence investigation on gadolinium gallium garnet nanocrystalline powders prepared by solution combustion synthesis Type A1 Journal article
Year 2007 Publication Nanotechnology Abbreviated Journal Nanotechnology
Volume 18 Issue 32 Pages 325604-325609
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract (up) Nanocrystalline powders of undoped and lanthanide (Pr3+, Tm3+)- doped gadolinium gallium garnet, Gd3Ga5O12 (GGG), were prepared by propellant synthesis and studied by x-ray powder diffraction (XRD), electron diffraction (ED), high-resolution electron microscopy (HREM) and luminescence spectroscopy. The x-ray diffraction patterns of the GGG samples were analysed using the Rietveld method. The Rietveld refinement reveals the existence of two garnet-type phases: both are cubic (space group Ia $(3) over bar $d) with a slightly different lattice parameter and probably a slightly different composition. Electron diffraction and electron microscopy measurements confirm the x-ray diffraction results. EDX measurements for lanthanide-doped samples show that stable solid solutions with composition Gd(3-x)Ln(x)Ga(5)O(12), x approximate to 0.3 ( Ln = Pr; Tm) have been obtained. The luminescence properties of the Tm3+ -doped nanocrystalline GGG samples were measured and analysed.
Address
Corporate Author Thesis
Publisher Place of Publication Bristol Editor
Language Wos 000248231300010 Publication Date 2007-07-14
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0957-4484;1361-6528; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.44 Times cited 33 Open Access
Notes Iap5-01 Approved Most recent IF: 3.44; 2007 IF: 3.310
Call Number UA @ lucian @ c:irua:104042 Serial 3195
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Author Laffez, P.; Lebedev, O.I.; Ruello, P.; Desfeux, R.; Banerjee, G.; Capon, F.
Title Evidence of strain induced structural change in hetero-epitaxial NdNiO3 thin films with metal-insulator transition Type A1 Journal article
Year 2004 Publication European physical journal: applied physics Abbreviated Journal Eur Phys J-Appl Phys
Volume 25 Issue 1 Pages 25-31
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract (up) Neodymium nickelate thin films have been prepared on NdGaO3 substrates by RF magnetron sputtering and post-annealing treatment under oxygen pressure. Transport properties are found to depend strongly on film thickness. Thick films show transport properties close to bulk ceramics, while very thin films exhibit a large transition from metal to insulator which occurs over a wide temperature range with high resistivity. Structure and surface morphology of the films have been investigated by Transmission Electron Microscopy (TEM) and Atomic Force Microscopy (AFM). Thin films (approximate to17 nm) grow heteroepitaxially, while thicker films (approximate to73 nm) show a granular structure. The thinnest sample suggests a symmetry change induced by the epitaxial strain of the substrate. This paper discusses the relationship between microstructure and transport properties.
Address
Corporate Author Thesis
Publisher Place of Publication Paris Editor
Language Wos 000187286000003 Publication Date 2003-12-15
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1286-0042;1286-0050; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 0.684 Times cited 12 Open Access
Notes Approved Most recent IF: 0.684; 2004 IF: 0.745
Call Number UA @ lucian @ c:irua:103256 Serial 1096
Permanent link to this record
 
 
Author Gasparotto, A.; Barreca, D.; Bekermann, D.; Devi, A.; Fischer, R.A.; Fornasiero, P.; Gombac, V.; Lebedev, O.I.; Maccato, C.; Montini, T.; Van Tendeloo, G.; Tondello, E.
Title F-doped Co3O4 photocatalysts for sustainable H2 generation from water/ethanol Type A1 Journal article
Year 2011 Publication Journal of the American Chemical Society Abbreviated Journal J Am Chem Soc
Volume 133 Issue 48 Pages 19362-19365
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract (up) p-Type Co3O4 nanostructured films are synthesized by a plasma-assisted process and tested in the photocatalytic production of H2 from water/ethanol solutions under both near-UV and solar irradiation. It is demonstrated that the introduction of fluorine into p-type Co3O4 results in a remarkable performance improvement with respect to the corresponding undoped oxide, highlighting F-doped Co3O4 films as highly promising systems for hydrogen generation. Notably, the obtained yields were among the best ever reported for similar semiconductor-based photocatalytic processes.
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000297606500027 Publication Date 2011-11-04
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0002-7863;1520-5126; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 13.858 Times cited 114 Open Access
Notes Approved Most recent IF: 13.858; 2011 IF: 9.907
Call Number UA @ lucian @ c:irua:93628 Serial 1164
Permanent link to this record
 
 
Author Lorenz, H.; Zhao, Q.; Turner, S.; Lebedev, O.I.; Van Tendeloo, G.; Kloetzer, B.; Rameshan, C.; Pfaller, K.
Title Origin of different deactivation of Pd/SnO2 and Pd/GeO2 catalysts in methanol dehydrogenation and reforming: a comparative study Type A1 Journal article
Year 2010 Publication Applied catalysis : A : general Abbreviated Journal Appl Catal A-Gen
Volume 381 Issue 1/2 Pages 242-252
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract (up) Pd particles supported on SnO2 and GeO2 have been structurally investigated by X-ray diffraction, (High-Resolution) transmission and scanning electron microscopy after different reductive treatments to monitor the eventual formation of bimetallic phases and catalytically tested in methanol dehydrogenation/ reforming. For both oxides this included a thin film sample with well-defined Pd particles and a powder catalyst prepared by incipient wetness impregnation. The hexagonal and the tetragonal polymorph were studied for powder GeO2. Pd2Ge formation was observed on all GeO2-supported catalysts, strongly depending on the specific sample used. Reduction of the thin film at 573K resulted in full transformation into the bimetallic state. The partial solubility of hexagonal GeO2 in water and its thermal structural instability yielded Pd2Ge formation at 473 K, at the cost of a structurally inhomogeneous support and Ge metal formation at higher reduction temperatures. Pd on tetragonal GeO2 entered a state of strong metalsupport interaction after reduction at 573673 K, resulting in coalescing Pd2Ge particles on a sintered and re-crystallized support, apparently partially covering the bimetallic particles and decreasing the catalytic activity. Pd2Ge on amorphous thin film and hexagonal GeO2 converted methanol primarily via dehydrogenation to CO and H2. At 573 K, formation of Pd2Sn and also PdSn occurred on the Pd/SnO2 thin film. Pd3Sn2 (and to some extent Pd2Sn) were predominantly obtained on the respective powder catalyst. Strong deactivation with increasing reduction temperature was observed, likely not based on the classical strong metalsupport interaction effect, but rather on a combination of missing active structural ensembles on Sn-enriched bimetallic phases and the formation of metallic -Sn. Correlations to Pd and its bimetallics supported on ZnO, Ga2O3 and In2O3 were also discussed.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000279100700029 Publication Date 2010-04-26
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0926-860X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.339 Times cited 14 Open Access
Notes Esteem 026019 Approved Most recent IF: 4.339; 2010 IF: 3.384
Call Number UA @ lucian @ c:irua:83927 Serial 2522
Permanent link to this record
 
 
Author Lin, K.; Lebedev, O.I.; Van Tendeloo, G.; Jacobs, P.A.; Pescarmona, P.P.
Title Titanosilicate beads with hierarchical porosity : synthesis and application as epoxidation catalysts Type A1 Journal article
Year 2011 Publication Chemistry: a European journal Abbreviated Journal Chem-Eur J
Volume 16 Issue 45 Pages 13509-13518
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract (up) Porous titanosilicate beads with a diameter of 0.51.5 mm (TiSil-HPB-60) were synthesized from a preformed titanosilicate solution with a porous anion-exchange resin as template. The bead format of this material enables its straightforward separation from the reaction mixture in its application as a liquid-phase heterogeneous catalyst. The material displays hierarchical porosity (micro/mesopores) and incipient TS-1 structure building units. The titanium species are predominantly located in tetrahedral framework positions. TiSil-HPB-60 is a highly active catalyst for the epoxidation of cyclohexene with t-butyl hydroperoxide (TBHP) and aqueous H2O2. With both oxidants, TiSil-HPB-60 gave higher epoxide yields than Ti-MCM-41 and TS-1. The improved catalytic performance of TiSil-HPB-60 is mainly ascribed to the large mesopores favoring the diffusion of reagents and products to and from the titanium active sites. The epoxide yield and selectivity could be further improved by silylation of the titanosilicate beads. Importantly, TiSil-HPB-60 is a stable catalyst immune to titanium leaching, and can be easily recovered and reused in successive catalytic cycles without significant loss of activity. Moreover, TiSil-HPB-60 is active and selective in the epoxidation of a wide range of bulky alkenes.
Address
Corporate Author Thesis
Publisher Place of Publication Weinheim Editor
Language Wos 000285398400029 Publication Date 2010-10-07
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0947-6539; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 5.317 Times cited 38 Open Access
Notes Iap; Goa Approved Most recent IF: 5.317; 2011 IF: 5.925
Call Number UA @ lucian @ c:irua:88153 Serial 3668
Permanent link to this record
 
 
Author Liu, S.; Lebedev, O.I.; Mertens, M.; Meynen, V.; Cool, P.; Van Tendeloo, G.; Vansant, E.F.
Title The merging of silica-surfactant microspheres under hydrothermal conditions Type A1 Journal article
Year 2008 Publication Microporous and mesoporous materials: zeolites, clays, carbons and related materials Abbreviated Journal Micropor Mesopor Mat
Volume 116 Issue Pages 141-146
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA)
Abstract (up) Post-synthesis hydrothermal treatments have been used to improve the quality of MCM-41 materials. In our latest work, merging of surfactant-containing silica microspheres during the hydrothermal treatments was observed. Mechanistic insights and the different stages that are involved in the merging process can be summarized as follows. First, the surfaces of the starting microspheres open up due to the dissolution of silica. Then the dissolved silica species provide mass source for the formation of particle necks connecting two neighboring microspheres. Gradually, surfaces of the starting microspheres are flattened to meet the needs of further growth of the necks. Finally, some chain-like highly-ordered mesoporous structures up to several micrometers are formed. The observed merging of the surfactant-containing microspheres is a re-assembling process, which is under the control of electrostatic force between the dissolved silica species and the surfactant cations. The occluded surfactant cations in the precursor spheres play important roles in the merging process.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000261133600021 Publication Date 2008-04-13
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1387-1811; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.615 Times cited 5 Open Access
Notes Fwo; Goa Approved Most recent IF: 3.615; 2008 IF: 2.555
Call Number UA @ lucian @ c:irua:72021 Serial 1997
Permanent link to this record
 
 
Author Gao, J.; Lebedev, O.I.; Turner, S.; Li, Y.F.; Lu, Y.H.; Feng, Y.P.; Boullay, P.; Prellier, W.; Van Tendeloo, G.; Wu, T.
Title Phase selection enabled formation of abrupt axial heterojunctions in branched oxide nanowires Type A1 Journal article
Year 2012 Publication Nano letters Abbreviated Journal Nano Lett
Volume 12 Issue 1 Pages 275-280
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract (up) Rational synthesis of nanowires via the vaporliquidsolid (VLS) mechanism with compositional and structural controls is vitally important for fabricating functional nanodevices from bottom up. Here, we show that branched indium tin oxide nanowires can be in situ seeded in vapor transport growth using tailored AuCu alloys as catalyst. Furthermore, we demonstrate that VLS synthesis gives unprecedented freedom to navigate the ternary InSnO phase diagram, and a rare and bulk-unstable cubic phase can be selectively stabilized in nanowires. The stabilized cubic fluorite phase possesses an unusual almost equimolar concentration of In and Sn, forming a defect-free epitaxial interface with the conventional bixbyite phase of tin-doped indium oxide that is the most employed transparent conducting oxide. This rational methodology of selecting phases and making abrupt axial heterojunctions in nanowires presents advantages over the conventional synthesis routes, promising novel composition-modulated nanomaterials.
Address
Corporate Author Thesis
Publisher Place of Publication Washington Editor
Language Wos 000298943100048 Publication Date 2011-12-05
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1530-6984;1530-6992; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 12.712 Times cited 25 Open Access
Notes Fwo Approved Most recent IF: 12.712; 2012 IF: 13.025
Call Number UA @ lucian @ c:irua:94209 Serial 2587
Permanent link to this record
 
 
Author Simoen, E.; Loo, R.; Claeys, C.; de Gryse, O.; Clauws, P.; van Landuyt, J.; Lebedev, O.
Title Optical spectroscopy of oxygen precipitates in heavily doped p-type silicon Type A1 Journal article
Year 2002 Publication Journal of physics : condensed matter T2 – Conference on Extended Defects in Semiconductors (EDS 2002), JUN 01-06, 2002, BOLOGNA, ITALY Abbreviated Journal J Phys-Condens Mat
Volume 14 Issue 48 Pages 13185-13193
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract (up) Results are presented on the photoluminescence (PL) characterization of heavily doped p(+) Czochralski silicon, which has been subjected to a two-step, oxygen precipitation heat treatment. It will be shown that the presence of oxygen precipitates gives rise to the D1, D2 and D5 lines, where the energy of the D1 line shifts to lower values for a stronger degree of precipitation. The occurrence of these PL features is also a function of the boron concentration in the p(+) material. The PL results are compared with Fourier transform infrared absorption data and with transmission electron microscope, results. From this, it is concluded that PL has a good potential for use in the assessment of oxygen precipitation in heavily doped silicon.
Address
Corporate Author Thesis
Publisher Place of Publication London Editor
Language Wos 000180091100068 Publication Date 2002-11-23
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0953-8984; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.649 Times cited 3 Open Access
Notes Approved Most recent IF: 2.649; 2002 IF: 1.775
Call Number UA @ lucian @ c:irua:103326 Serial 2477
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Author Morozov, V.A.; Lazoryak, B.I.; Shmurak, S.Z.; Kiselev, A.P.; Lebedev, O.I.; Gauquelin, N.; Verbeeck, J.; Hadermann, J.; Van Tendeloo, G.
Title Influence of the structure on the properties of NaxEuy(MoO4)z red phosphors Type A1 Journal article
Year 2014 Publication Chemistry of materials Abbreviated Journal Chem Mater
Volume 26 Issue 10 Pages 3238-3248
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract (up) Scheelite related compounds (A',A '')(n)[(B',B '')O-4](m) with B', B '' = W and/or Mo are promising new materials for red phosphors in pc-WLEDs (phosphor-converted white-light-emitting-diode) and solid-state lasers. Cation substitution in CaMoO4 of Ca2+ by the combination of Na+ and Eu3+, with the creation of A cation vacancies, has been investigated as a factor for controlling the scheelite-type structure and the luminescent properties. Na5Eu(MoO4)(4) and NaxEu(2-x)/33+square(2-x)/3MoO4 (0.138 <= x <= 0.5) phases with a scheelite-type structure were synthesized by the solid state method; their structural characteristics were investigated using transmission electron microscopy. Contrary to powder synchrotron X-ray diffraction before, the study by electron diffraction and high resolution transmission electron microscopy in this paper revealed that Na0.286Eu0.571MoO4 has a (3 + 2)D incommensurately modulated structure and that (3 + 2)D incommensurately modulated domains are present in Na0.200Eu0.600MoO4. It also confirmed the (3 + 1)D incommensurately modulated character of Na(0.138)Eu(0.621)Mo04. The luminescent properties of all phases under near-ultraviolet (n-UV) light have been investigated. The excitation spectra of these phosphors show the strongest absorption at about 395 nm, which matches well with the commercially available n-UV-emitting GaN-based LED chip. The emission spectra indicate an intense red emission due to the D-5(0) -> F-7(2) transition of Eu3+, with local minima in the intensity at Na0.286Eu0.571MoO4 and Na0.200Eu0.600MoO4 for similar to 613 nm and similar to 616 nm bands. The phosphor Na5Eu(MoO4)(4) shows the brightest red light emission among the phosphors in the Na2MoO4-Eu2/3MoO4 system and the maximum luminescence intensity of Na5Eu(MoO4)(4) (lambda(ex) = 395 nm) in the D-5(0) -> F-7(2) transition region is close to that of the commercially used red phosphor YVO4:Eu3+ (lambda(ex) = 326 nm). Electron energy loss spectroscopy measurements revealed the influence of the structure and Na/Eu cation distribution on the number and positions of bands in the UV-optical-infrared regions of the EELS spectrum.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000336637000028 Publication Date 2014-05-01
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0897-4756;1520-5002; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 9.466 Times cited 53 Open Access
Notes Fwo G039211n; Fwo G004413n; 278510 Vortex ECASJO_; Approved Most recent IF: 9.466; 2014 IF: 8.354
Call Number UA @ lucian @ c:irua:117765UA @ admin @ c:irua:117765 Serial 1652
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Author Morozov, V.; Arakcheeva, A.; Redkin, B.; Sinitsyn, V.; Khasanov, S.; Kudrenko, E.; Raskina, M.; Lebedev, O.; Van Tendeloo, G.
Title Na2/7Gd4/7MoO4 : a modulated scheelite-type structure and conductivity properties Type A1 Journal article
Year 2012 Publication Inorganic chemistry Abbreviated Journal Inorg Chem
Volume 51 Issue 9 Pages 5313-5324
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract (up) Scheelite-type compounds with the general formula (A1,A2)n[(B1,B2)O4]m (2/3 ≤ n/m ≤ 3/2) are the subject of large interest owing to their stability, relatively simple preparation, and optical properties. The creation of cation vacancies (□) in the scheelite-type framework and the ordering of A cations and vacancies can be a new factor in controlling the scheelite-type structure and properties. For a long time, cation-deficient Nd3+:M2/7Gd4/7□1/7MoO4 (M = Li, Na) compounds were considered as potential lasers with diode pumping. They have a defect scheelite-type 3D structure (space group I41/a) with a random distribution of Li+(Na+), Gd3+, and vacancies in the crystal. A Na2/7Gd4/7MoO4 single crystal with scheelite-type structure has been grown by the Czochralski method. Transmission electron microscopy revealed that Na2/7Gd4/7MoO4 has a (3 + 2)D incommensurately modulated structure. The (3 + 2)D incommensurately modulated scheelite-type cation-deficient structure of Na2/7Gd4/7MoO4 [super space group I4̅ (αβ0,βα0)00] has been solved from single-crystal diffraction data. The solution of the (3 + 2)D incommensurately modulated structure revealed the partially disordered distribution of vacancies and Na and Gd cations. High-temperature conductivity measurements performed along the [100] and [001] orientation of the single crystal revealed that the conductivity of Na2/7Gd4/7MoO4 at T = 973 K equals σ = 1.13 × 105 Ω1 cm1.
Address
Corporate Author Thesis
Publisher Place of Publication Easton, Pa Editor
Language Wos 000303952900055 Publication Date 2012-04-19
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0020-1669;1520-510X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.857 Times cited 37 Open Access
Notes Approved Most recent IF: 4.857; 2012 IF: 4.593
Call Number UA @ lucian @ c:irua:98385 Serial 3547
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Author Xu, T.; Nys, J.-P.; Addad, A.; Lebedev, O.I.; Urbieta, A.; Salhi, B.; Berthe, M.; Grandidier, B.; Stievenard, D.
Title Faceted sidewalls of silicon nanowires: Au-induced structural reconstructions and electronic properties Type A1 Journal article
Year 2010 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 81 Issue 11 Pages 115403,1-115403,10
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract (up) Si nanowires with a ⟨111⟩ orientation, synthesized by vapor-liquid-solid process with low silane partial pressure reactant and gold as the catalyst, are known to exhibit sawtooth facets containing gold adsorbates. We report herein the study of the nanowire morphology by means of transmission electron microscopy and scanning tunneling microscopy. The nanowires consist of faceted sidewalls. The number of the sidewalls changes from 12 to 6 along the growth axis, giving rise to nanowires with an irregular hexagonal cross section at their base. The sidewalls are covered with Au-rich clusters. Their facets also exhibit atomic structures that reveal the presence of gold, resulting from the diffusion of gold during the growth. Based on these observations, the tapering of the nanowire is found to be related to two contributions: the reduction in the catalyst particle size during the growth and lateral overgrowth from the direct incorporation of Si species onto the nanowire sidewalls. Because the rearrangement of atoms at surfaces and interfaces might affect the growth kinetics, the trigonal symmetry as well as the higher lateral growth rate on the widest sidewalls are explained from the existence of an interfacial atomic structure with two inequivalent parts in the unit cell. Finally, spectroscopic measurements were performed on the major facets and revealed a metallic behavior at 77 K.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000276248800116 Publication Date 2010-03-03
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 42 Open Access
Notes Approved Most recent IF: 3.836; 2010 IF: 3.774
Call Number UA @ lucian @ c:irua:82273 Serial 1168
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Author Carraro, G.; Maccato, C.; Bontempi, E.; Gasparotto, A.; Lebedev, O.I.; Turner, S.; Depero, L.E.; Van Tendeloo, G.; Barreca, D.
Title Insights on growth and nanoscopic investigation of uncommon iron oxide polymorphs Type A1 Journal article
Year 2013 Publication European journal of inorganic chemistry Abbreviated Journal Eur J Inorg Chem
Volume Issue 31 Pages 5454-5461
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract (up) Si(100)-supported Fe2O3 nanomaterials were developed by a chemical vapor deposition (CVD) approach. The syntheses, which were performed at temperatures between 400 and 550 °C, selectively yielded the scarcely studied β- and ϵ-Fe2O3 polymorphs under O2 or O2 + H2O reaction environments, respectively. Correspondingly, the observed morphology underwent a progressive evolution from interconnected nanopyramids to vertically aligned nanorods. The present study aims to provide novel insights into Fe2O3 nano-organization by a systematic investigation of the system structure/morphology and of their interrelations with growth conditions. In particular, for the first time, the β- and ϵ-Fe2O3 preparation process has been accompanied by a thorough multitechnique investigation, which, beyond X-ray photoelectron spectroscopy (XPS) and field-emission scanning electron microscopy (FESEM), is carried out by X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDXS), atomic force microscopy (AFM), high-resolution transmission electron microscopy (HRTEM), electron diffraction (ED), scanning TEM electron energy-loss spectroscopy (STEM-EELS), and high-angle annular dark-field STEM (HAADF-STEM). Remarkably, the target materials showed a high structural and compositional homogeneity throughout the whole thickness of the nanodeposit. In particular, spatially resolved EELS chemical maps through the spectrum imaging (SI) technique enabled us to gain important information on the local Fe coordination, which is of crucial importance in determining the system reactivity. The described preparation method is in fact a powerful tool to simultaneously tailor phase composition and morphology of iron(III) oxide nanomaterials, the potential applications of which include photocatalysis, magnetic devices, gas sensors, and anodes for Li-ion batteries.
Address
Corporate Author Thesis
Publisher Place of Publication Weinheim Editor
Language Wos 000330567000009 Publication Date 2013-10-08
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1434-1948; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.444 Times cited 18 Open Access
Notes Fwo; Countatoms Approved Most recent IF: 2.444; 2013 IF: 2.965
Call Number UA @ lucian @ c:irua:110946 Serial 1676
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Author Godefroo, S.; Hayne, M.; Jivanescu, M.; Stesmans, A.; Zacharias, M.; Lebedev, O.I.; Van Tendeloo, G.; Moshchalkov, V.V.
Title Classification and control of the origin of photoluminescence from Si nanocrystals Type A1 Journal article
Year 2008 Publication Nature nanotechnology Abbreviated Journal Nat Nanotechnol
Volume 3 Issue 3 Pages 174-178
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract (up) Silicon dominates the electronics industry, but its poor optical properties mean that III-V compound semiconductors are preferred for photonics applications. Photoluminescence at visible wavelengths was observed from porous Si at room temperature in 1990, but the origin of these photons (do they arise from highly localized defect states or quantum confinement effects?) has been the subject of intense debate ever since. Attention has subsequently shifted from porous Si to Si nanocrystals, but the same fundamental question about the origin of the photoluminescence has remained. Here we show, based on measurements in high magnetic fields, that defects are the dominant source of light from Si nanocrystals. Moreover, we show that it is possible to control the origin of the photoluminescence in a single sample: passivation with hydrogen removes the defects, resulting in photoluminescence from quantum-confined states, but subsequent ultraviolet illumination reintroduces the defects, making them the origin of the light again.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000254743600017 Publication Date 2008-03-02
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1748-3387;1748-3395; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 38.986 Times cited 426 Open Access
Notes Fwo Approved Most recent IF: 38.986; 2008 IF: 20.571
Call Number UA @ lucian @ c:irua:102630 Serial 373
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Author Turner, S.; Lebedev, O.I.; Shenderova, O.; Vlasov, I.I.; Verbeeck, J.; Van Tendeloo, G.
Title Determination of size, morphology, and nitrogen impurity location in treated detonation nanodiamond by transmission electron microscopy Type A1 Journal article
Year 2009 Publication Advanced functional materials Abbreviated Journal Adv Funct Mater
Volume 19 Issue 13 Pages 2116-2124
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract (up) Size, morphology, and nitrogen impurity location, all of which are all thought to be related to the luminescent properties of detonation nanodiamonds, are determined in several detonation nanodiamond samples using a combination of transmission electron microscopy techniques. Results obtained from annealed and cleaned detonation nanodiamond samples are compared to results from conventionally purified detonation nanodiamond. Detailed electron energy loss spectroscopy combined with model-based quantification provides direct evidence for the sp3 like embedding of nitrogen impurities into the diamond cores of all the studied nanodiamond samples. Simultaneously, the structure and morphology of the cleaned detonation nanodiamond particles are studied using high resolution transmission electron microscopy. The results show that the size and morphology of detonation nanodiamonds can be modified by temperature treatment and that by applying a special cleaning procedure after temperature treatment, nanodiamond particles with clean facets almost free from sp2 carbon can be prepared. These clean facets are clear evidence that nanodiamond cores are not necessarily in coexistence with a graphitic shell of non-diamond carbon.
Address
Corporate Author Thesis
Publisher Place of Publication Weinheim Editor
Language Wos 000268297800012 Publication Date 2009-05-12
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1616-301X;1616-3028; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 12.124 Times cited 100 Open Access
Notes Esteem 026019 Approved Most recent IF: 12.124; 2009 IF: 6.990
Call Number UA @ lucian @ c:irua:78261UA @ admin @ c:irua:78261 Serial 674
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Author Bekermann, D.; Gasparotto, A.; Barreca, D.; Bovo, L.; Devi, A.; Fischer, R.A.; Lebedev, O.I.; Maccato, C.; Tondello, E.; Van Tendeloo, G.
Title Highly oriented ZnO nanorod arrays by a novel plasma chemical vapor deposition process Type A1 Journal article
Year 2010 Publication Crystal growth & design Abbreviated Journal Cryst Growth Des
Volume 10 Issue 4 Pages 2011-2018
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract (up) Strongly c-axis oriented ZnO nanorod arrays were grown on Si(100) by plasma enhanced-chemical vapor deposition (PE-CVD) starting from two volatile bis(ketoiminato) zinc(II) compounds Zn[(R′)NC(CH3)═C(H)C(CH3)═O]2, with R′ = -(CH2)xOCH3 (x = 2, 3). A systematic investigation of process parameters enabled us to obtain the selective formation of ZnO nanorods with tailored features, and provided an important insight into their growth mechanism. The morphology, structure, and composition of the synthesized ZnO nanosystems were thoroughly analyzed by field emission-scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDXS), glancing incidence X-ray diffraction (GIXRD), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). Photoluminescence (PL) measurements were carried out to gain information on the optical properties. Specifically, one-dimensional (1D) ZnO architectures could be grown on Si(100) substrates at temperatures as low as 200−300 °C and radio frequency (RF)-power values of 20 W, provided that a sufficiently high mass supply to the growth surface was maintained. To the best of our knowledge, the present work reports the mildest preparation conditions ever appeared in the literature for the PE-CVD of ZnO nanorods, a key result in view of potential large-scale technological applications.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000276234500080 Publication Date 2010-03-18
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1528-7483;1528-7505; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.055 Times cited 75 Open Access
Notes Esteem 026019 Approved Most recent IF: 4.055; 2010 IF: 4.390
Call Number UA @ lucian @ c:irua:82311 Serial 1472
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Author Verbist, K.; Lebedev, O.I.; Van Tendeloo, G.; Verhoeven, M.A.J.; Rijnders, A.J.H.M.; Blank, D.H.A.
Title Study of ramp-type Josephson junctions by HREM Type A1 Journal article
Year 1997 Publication Electronic Applications; Vol 2: Large Scale And Power Applications Abbreviated Journal
Volume Issue 158 Pages 49-52
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract (up) Structural aspects of ramp-type Josephson junctions based on REBa2Cu3O7-delta high-T-c superconductors, are investigated by cross-section transmission electron microscopy and results related to fabrication process or physical properties. The barrier layer material is PrBa2Cu3-xGaxO7-delta. The ramp-geometry depends on the etching conditions. High levels of Ga doping (x>0.7) influence the microstructure of the barrier layer thereby changing the junctions properties.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000071955200012 Publication Date 0000-00-00
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0-7503-0487-1 ISBN Additional Links UA library record; WoS full record;
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ lucian @ c:irua:102941 Serial 3333
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Author Zhao, Q.; Lorenz, H.; Turner, S.; Lebedev, O.I.; Van Tendeloo, G.; Rameshan, C.; Klötzer, B.; Konzett, J.; Penner, S.
Title Catalytic characterization of pure SnO2 and GeO2 in methanol steam reforming Type A1 Journal article
Year 2010 Publication Applied catalysis : A : general Abbreviated Journal Appl Catal A-Gen
Volume 375 Issue 2 Pages 188-195
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract (up) Structural changes of a variety of different SnO, SnO2 and GeO2 catalysts upon reduction in hydrogen were correlated with associated catalytic changes in methanol steam reforming. Studied systems include SnO, SnO2 and GeO2 thin film model catalysts prepared by vapour phase deposition and growth on polycrystalline NaCl surfaces and, for comparison, the corresponding pure oxide powder catalysts. Reduction of both the SnO2 thin film and powder at around 673 K in 1 bar hydrogen leads to a substantial reduction of the bulk structure and yields a mixture of SnO2 and metallic β-Sn. On the powder catalyst this transformation is fully reversible upon oxidation in 1 bar O2 at 673 K. Strongly reduced thin films, however, can only be re-transformed to SnO2 if the reduction temperature did not exceed 573 K. For GeO2, the situation is more complex due to its polymorphism. Whereas the tetragonal phase is structurally stable during reduction, oxidation or catalytic reaction, a small part of the hexagonal phase is always transformed into the tetragonal at 673 K independent of the gas phase used. SnO2 is highly active and CO2 selective in methanol steam reforming, but the initial high activity drops considerably upon reduction between 373 and 573 K and almost complete catalyst deactivation is observed after reduction at 673 K, which is associated with the parallel formation of β-Sn. In close correlation to the structural results, the catalytic activity and selectivity can be restored upon an oxidative catalyst regeneration at 673 K. Tetragonal GeO2 exhibits only a small activity and no pronounced selectivity to either CO or CO2, at least after reduction. In its fully oxidized state release of surface/lattice oxygen results in a non-catalytic formation of CO2 by oxidation of CO originating from catalytic dehydrogenation.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000275580600002 Publication Date 2010-01-15
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0926-860X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.339 Times cited 20 Open Access
Notes Esteem 026019 Approved Most recent IF: 4.339; 2010 IF: 3.384
Call Number UA @ lucian @ c:irua:81741 Serial 292
Permanent link to this record
 
 
Author Lebedev, O.I.; Caignaert, V.; Raveau, B.; Pop, N.; Gozzo, F.; Van Tendeloo, G.; Pralong, V.
Title HRTEM and neutron diffraction study of LixMo5O17 : from the ribbon (x=5) structure to the rock salt (x=12) structure Type A1 Journal article
Year 2011 Publication Journal of solid state chemistry Abbreviated Journal J Solid State Chem
Volume 184 Issue 4 Pages 790-796
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract (up) Structure determination of the fully intercalated phase Li12Mo5O17 and of the deintercalated oxide Li5Mo5O17 has been carried out by electron microscopy and neutron powder diffraction. The reversible topotactic transformation between the ordered rock salt structure of the former and the ribbon structure of the latter (closely related to that of Li4Mo5O17) is explained on the following basis: both structures can be described as strips built up as an assembly of infinite ribbons of MoO6 octahedra that are five octahedra thick, and that differ by slight displacements of the octahedral ribbons. We show that the electrochemical behavior of the LixMo5O17 system is based on two sorts of Li+ sites; those that are located within the strips between the ribbons, and those that are located at the border of the strips. The high rate of Li intercalation in this oxide and its reversibility are discussed in terms of its peculiar structure.
Address
Corporate Author Thesis
Publisher Place of Publication London Editor
Language Wos 000289597100010 Publication Date 2011-02-12
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0022-4596; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.299 Times cited 1 Open Access
Notes Esteem 026019 Approved Most recent IF: 2.299; 2011 IF: 2.159
Call Number UA @ lucian @ c:irua:88646 Serial 1515
Permanent link to this record
 
 
Author Lorenz, H.; Zhao, Q.; Turner, S.; Lebedev, O.I.; Van Tendeloo, G.; Klötzer, B.; Rameshan, C.; Penner, S.
Title Preparation and structural characterization of SnO2 and GeO2 methanol steam reforming thin film model catalysts by (HR)TEM Type A1 Journal article
Year 2010 Publication Materials chemistry and physics Abbreviated Journal Mater Chem Phys
Volume 122 Issue 2/3 Pages 623-629
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract (up) Structure, morphology and composition of different tin oxide and germanium oxide thin film catalysts for the methanol steam reforming (MSR) reaction have been studied by a combination of (high-resolution) transmission electron microscopy, selected area electron diffraction, dark-field imaging and electron energy-loss spectroscopy. Deposition of the thin films on NaCl(0 0 1) cleavage faces has been carried out by thermal evaporation of the respective SnO2 and GeO2 powders in varying oxygen partial pressures and at different substrate temperatures. Preparation of tin oxide films in high oxygen pressures (10−1 Pa) exclusively resulted in SnO phases, at and above 473 K substrate temperature epitaxial growth of SnO on NaCl(0 0 1) leads to well-ordered films. For lower oxygen partial pressures (10−3 to 10−2 Pa), mixtures of SnO and β-Sn are obtained. Well-ordered SnO2 films, as verified by electron diffraction patterns and energy-loss spectra, are only obtained after post-oxidation of SnO films at temperatures T ≥ 673 K in 105 Pa O2. Preparation of GeOx films inevitably results in amorphous films with a composition close to GeO2, which cannot be crystallized by annealing treatments in oxygen or hydrogen at temperatures comparable to SnO/SnO2. Similarities and differences to neighbouring oxides relevant for selective MSR in the third group of the periodic system (In2O3 and Ga2O3) are also discussed with the aim of cross-correlation in formation of nanomaterials, and ultimately, also catalytic properties.
Address
Corporate Author Thesis
Publisher Place of Publication Lausanne Editor
Language Wos 000278637900054 Publication Date 2010-04-18
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0254-0584; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.084 Times cited 15 Open Access
Notes Esteem 026019 Approved Most recent IF: 2.084; 2010 IF: 2.356
Call Number UA @ lucian @ c:irua:83099 Serial 2699
Permanent link to this record
 
 
Author Canioni, R.; Roch-Marchal, C.; Sécheresse, F.; Horcajada, P.; Serre, C.; Hardi-Dan, M.; Férey, G.; Grenèche, J.-M.; Lefebvre, F.; Chang, J.-S.; Hwang, Y.-K.; Lebedev, O.; Turner, S.; Van Tendeloo, G.
Title Stable polyoxometalate insertion within the mesoporous metal organic framework MIL-100(Fe) Type A1 Journal article
Year 2011 Publication Journal of materials chemistry Abbreviated Journal J Mater Chem
Volume 21 Issue 4 Pages 1226-1233
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract (up) Successful encapsulation of polyoxometalate (POM) within the framework of a mesoporous iron trimesate MIL-100(Fe) sample has been achieved by direct hydrothermal synthesis in the absence of fluorine. XRPD, 31P MAS NMR, IR, EELS, TEM and 57Fe Mössbauer spectrometry corroborate the insertion of POM within the cavities of the MOF. The experimental Mo/Fe ratio is 0.95, in agreement with the maximum theoretical amount of POM loaded within the pores of MIL-100(Fe), based on steric hindrance considerations. The POM-MIL-100(Fe) sample exhibits a pore volume of 0.373 cm3 g−1 and a BET surface area close to 1000 m2 g−1, indicating that small gas molecules can easily diffuse inside the cavities despite the presence of heavy phosphomolybdates. These latter contribute to the decrease in the overall surface area, due to the increase in molar weight, by 65%. Moreover, the resulting Keggin containing MIL-100(Fe) solid is stable in aqueous solution with no POM leaching even after more than 2 months. In addition, no exchange of the Keggin anions by tetrabutylammonium perchlorate in organic media has been observed.
Address
Corporate Author Thesis
Publisher Place of Publication Cambridge Editor
Language Wos 000286110400042 Publication Date 2010-11-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0959-9428;1364-5501; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited 158 Open Access
Notes Approved Most recent IF: NA
Call Number UA @ lucian @ c:irua:88642 Serial 3145
Permanent link to this record
 
 
Author Carraro, G.; Maccato, C.; Gasparotto, A.; Montini, T.; Turner, S.; Lebedev, O.I.; Gombac, V.; Adami, G.; Van Tendeloo, G.; Barreca, D.; Fornasiero, P.;
Title Enhanced hydrogen production by photoreforming of renewable oxygenates through nanostructured Fe2O3 polymorphs Type A1 Journal article
Year 2014 Publication Advanced functional materials Abbreviated Journal Adv Funct Mater
Volume 24 Issue 3 Pages 372-378
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract (up) Sunlight-driven hydrogen production via photoreforming of aqueous solutions containing renewable compounds is an attractive option for sustainable energy generation with reduced carbon footprint. Nevertheless, the absence of photocatalysts combining high efficiency and stability upon solar light activation has up to date strongly hindered the development of this technology. Herein, two scarcely investigated iron(III) oxide polymorphs, β- and ε-Fe2O3, possessing a remarkable activity in sunlight-activated H2 generation from aqueous solutions of renewable oxygenates (i.e., ethanol, glycerol, glucose) are reported. For β-Fe2O3 and ε-Fe2O3, H2 production rates up to 225 and 125 mmol h−1 m−2 are obtained, with significantly superior performances with respect to the commonly investigated α-Fe2O3.
Address
Corporate Author Thesis
Publisher Place of Publication Weinheim Editor
Language Wos 000332832500011 Publication Date 2013-10-08
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1616-301X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 12.124 Times cited 95 Open Access
Notes Countatoms; Hercules; Fwo Approved Most recent IF: 12.124; 2014 IF: 11.805
Call Number UA @ lucian @ c:irua:113090 Serial 1051
Permanent link to this record