“Coupled cation and charge ordering in the CaMn306 tunnel structure”. Hadermann J, Abakumov AM, Gillie LJ, Martin C, Hervieu M, Chemistry of materials 18, 5530 (2006). http://doi.org/10.1021/cm0618998
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 9.466
Times cited: 33
DOI: 10.1021/cm0618998
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“Highly disordered crystal structure and thermoelectric properties of Sn3P4”. Zaikina JV, Kovnir KA, Sobolev AN, Presniakov IA, Kytin VG, Kulbachinskii VA, Olenev AV, Lebedev OI, Van Tendeloo G, Dikarev EV, Shevelkov AV, Chemistry of materials 20, 2476 (2008). http://doi.org/10.1021/cm702655g
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 9.466
Times cited: 33
DOI: 10.1021/cm702655g
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“Mn(I) in an extended oxide : the synthesis and characterization of La1-xCaxMnO2+\delta (0.6\leq x\leq1)”. Dixon E, Hadermann J, Ramos S, Goodwin AL, Hayward MA, Journal of the American Chemical Society 133, 18397 (2011). http://doi.org/10.1021/ja207616c
Abstract: Reduction of La1xCaxMnO3 (0.6 ≤ x ≤ 1) perovskite phases with sodium hydride yields materials of composition La1xCaxMnO2+δ. The calcium-rich phases (x = 0.9, 1) adopt (La0.9Ca0.1)0.5Mn0.5O disordered rocksalt structures. However local structure analysis using reverse Monte Carlo refinement of models against pair distribution functions obtained from neutron total scattering data reveals lanthanum-rich La1xCaxMnO2+δ (x = 0.6, 0.67, 0.7) phases adopt disordered structures consisting of an intergrowth of sheets of MnO6 octahedra and sheets of MnO4 tetrahedra. X-ray absorption data confirm the presence of Mn(I) centers in La1xCaxMnO2+δ phases with x < 1. Low-temperature neutron diffraction data reveal La1xCaxMnO2+δ (x = 0.6, 0.67, 0.7) phases become antiferromagnetically ordered at low temperature.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 13.858
Times cited: 33
DOI: 10.1021/ja207616c
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“Multimodal zeolite-beta-based catalysts with a hierarchical, three-level pore structure”. Chen L-H, Li X-Y, Tian G, Li Y, Tan H-Y, Van Tendeloo G, Zhu G-S, Qiu S-L, Yang X-Y, Su B-L, Chemsuschem 4, 1452 (2011). http://doi.org/10.1002/cssc.201100181
Abstract: Hole diggers: The hierarchically structured porous solid-acid catalyst described in this report possess a remarkable pore system, encompassing well-defined macrochannels, interconnected mesopores, intracrystalline mesopores, and tunable zeolite micropores. Importantly, the catalyst exhibits very strong acidity and superior catalytic activity for esterification reactions.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 7.226
Times cited: 33
DOI: 10.1002/cssc.201100181
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“The fine structure of YCuO2+x delafossite determined by synchrotron powder diffraction and electron microscopy”. Van Tendeloo G, Garlea O, Darie C, Bougerol-Chaillout C, Bordet P, Journal of solid state chemistry 156, 428 (2001). http://doi.org/10.1006/jssc.2000.9018
Abstract: YCuO2 delafossite crystallizes into two stacking variants; hexagonal 2H or rhombohedral 3R, depending on the preparation conditions. The structure of the fully oxygenated material YCuO2.50 has been determined as orthorhombic (a(O) = 6.1961 Angstrom; b(O) = 11.2158 Angstrom; c(O) = 7.1505 Angstrom; space group Pnma). The structure is based on the hexagonal 2H structure (a(O) = a(H)root3; b(O) = c(H); c(O) = 2a(H)). Upon incomplete oxidation, a different YCuOZ phase with ideal composition YCuO2.33 and lattice parameters a(H root)3, a(H)root3, c(H) is also formed. Diffraction patterns are often very complex because of the presence of planar defects and intergrowth of both phases. Under electron beam irradiation, oxygen is released from the structure and one phase gradually transforms into the other. (C) 2001 Academic Press.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.299
Times cited: 33
DOI: 10.1006/jssc.2000.9018
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“1D-2D-3D Transformation Synthesis of Hierarchical Metal-Organic Framework Adsorbent for Multicomponent Alkane Separation”. Wee LH, Meledina M, Turner S, Van Tendeloo G, Zhang K, Marleny Rodriguez-Albelo L, Masala A, Bordiga S, Jiang J, Navarro JAR, Kirschhock CEA, Martens JA, Journal of the American Chemical Society 139, 819 (2017). http://doi.org/10.1021/JACS.6B10768
Abstract: A new hierarchical MOF consisting of Cu(II) centers connected by benzene-tricarboxylates (BTC) is prepared by thermoinduced solid transformation of a dense CuBTC precursor phase. The mechanism of the material formation has been thoroughly elucidated and revealed a transformation of a ribbon-like 1D building unit into 2D layers and finally a 3D network. The new phase contains excess copper, charge compensated by systematic hydroxyl groups, which leads to an open microporous framework with tunable permanent mesoporosity. The new phase is particularly attractive for molecular separation. Energy consumption of adsorptive separation processes can be lowered by using adsorbents that discriminate molecules based on adsorption entropy rather than enthalpy differences. In separation of a 11-component mixture of C-1-C-6 alkanes, the hierarchical phase outperforms the structurally related microporous HKUST-1 as well as silicate-based hierarchical materials. Grand canonical Monte Carlo (GCMC) simulation provides microscopic insight into the structural host-guest interaction, confirming low adsorption enthalpies and significant entropic contributions to the molecular separation. The unique three-dimensional hierarchical structure as well as the systematic presence of Cu(II) unsaturated coordination sites cause this exceptional behavior.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 13.858
Times cited: 33
DOI: 10.1021/JACS.6B10768
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“Mono- and Multilayer Silicene-Type Honeycomb Lattices by Oriented Attachment of PbSe Nanocrystals: Synthesis, Structural Characterization, and Analysis of the Disorder”. Peters JL, Altantzis T, Lobato I, Jazi MA, van Overbeek C, Bals S, Vanmaekelbergh D, Sinai SB, Chemistry of materials 30, 4831 (2018). http://doi.org/10.1021/acs.chemmater.8b02178
Abstract: Nanocrystal (NC) solids are commonly prepared from nonpolar organic NC suspensions. In many cases, the capping on the NC surface is preserved and forms a barrier between the NCs. More recently, superstructures with crystalline connections between the NCs, implying the removal of the capping, have been reported, too. Here, we present large-scale uniform superstructures of attached PbSe NCs with a silicene-type honeycomb geometry, resulting from solvent evaporation under nearly reversible conditions. We also prepared multilayered silicene honeycomb structures by using larger amounts of PbSe NCs. We show that the two-dimensional silicene superstructures can be seen as a crystallographic slice from a 3-D simple cubic structure. We describe the disorder in the silicene lattices in terms of the nanocrystals position and their atomic alignment. The silicene honeycomb sheets are large enough to be used in transistors and optoelectronic devices.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 9.466
Times cited: 33
DOI: 10.1021/acs.chemmater.8b02178
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“Atomic spectroscopy”. Bings NH, Bogaerts A, Broekaert JAC, Analytical chemistry 76, 3313 (2004). http://doi.org/10.1021/ac040052x
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 6.32
Times cited: 32
DOI: 10.1021/ac040052x
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“Hyperthermal oxidation of Si(100)2x1 surfaces : effect of growth temperature”. Khalilov U, Pourtois G, van Duin ACT, Neyts EC, The journal of physical chemistry: C : nanomaterials and interfaces 116, 8649 (2012). http://doi.org/10.1021/jp300506g
Abstract: Using reactive molecular dynamics simulations based on the ReaxFF potential, we studied the growth mechanism of ultrathin silica (SiO2) layers during hyperthermal oxidation as a function of temperature in the range 100-1300 K. Oxidation of Si(100){2 x 1} surfaces by both atomic and molecular oxygen was investigated for hyperthermal impact energies in the range of 1 to 5 eV. Two different growth mechanisms are found, corresponding to a low temperature oxidation and a high temperature one. The transition temperature between these mechanisms is estimated to be about 700 K. Also, the initial step of the Si oxidation process is analyzed in detail. Where possible, we validated our results with experimental and ab initio data, and good agreement was obtained. This study is important for the fabrication of silica-based devices in the micro- and nanoelectronics industry and, more specifically, for the fabrication of metal oxide semiconductor devices.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.536
Times cited: 32
DOI: 10.1021/jp300506g
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“Microprobe speciation analysis of inorganic solids by Fourier transform laser mass spectrometry”. Poels K, van Vaeck L, Gijbels R, Analytical chemistry 70, 504 (1998). http://doi.org/10.1021/ac9709108
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 6.32
Times cited: 32
DOI: 10.1021/ac9709108
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“Nanocrystals of lead chalcohalides : a series of kinetically trapped metastable nanostructures”. Toso S, Akkerman QA, Martin-Garcia B, Prato M, Zito J, Infante I, Dang Z, Moliterni A, Giannini C, Bladt E, Lobato I, Ramade J, Bals S, Buha J, Spirito D, Mugnaioli E, Gemmi M, Manna L, Journal Of The American Chemical Society 142, 10198 (2020). http://doi.org/10.1021/JACS.0C03577
Abstract: We report the colloidal synthesis of a series of surfactant-stabilized lead chalcohalide nanocrystals. Our work is mainly focused on Pb4S3Br2, a chalcohalide phase unknown to date that does not belong to the ambient-pressure PbS-PbBr2 phase diagram. The Pb4S3Br2 nanocrystals herein feature a remarkably narrow size distribution (with a size dispersion as low as 5%), a good size tunability (from 7 to similar to 30 nm), an indirect bandgap, photoconductivity (responsivity = 4 +/- 1 mA/W), and stability for months in air. A crystal structure is proposed for this new material by combining the information from 3D electron diffraction and electron tomography of a single nanocrystal, X-ray powder diffraction, and density functional theory calculations. Such a structure is closely related to that of the recently discovered high-pressure chalcohalide Pb4S3I2 phase, and indeed we were able to extend our synthesis scheme to Pb4S3I2 colloidal nanocrystals, whose structure matches the one that has been published for the bulk. Finally, we could also prepare nanocrystals of Pb3S2Cl2, which proved to be a structural analogue of the recently reported bulk Pb3Se2Br2 phase. It is remarkable that one high-pressure structure (for Pb4S3I2) and two metastable structures that had not yet been reported (for Pb4S3Br2 and Pb3S2Cl2) can be prepared on the nanoscale by wet-chemical approaches. This highlights the important role of colloidal chemistry in the discovery of new materials and motivates further exploration into metal chalcohalide nanocrystals.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 15
Times cited: 32
DOI: 10.1021/JACS.0C03577
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“Anion ordering and defect structure in Ruddlesden-Popper strontium niobium oxynitrides”. Tobías G, Beltrán-Porter D, Lebedev OI, Van Tendeloo G, Rodríguez-Carvajal J, Fuertes A, Inorganic chemistry 43, 8010 (2004). http://doi.org/10.1021/ic049236k
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.857
Times cited: 31
DOI: 10.1021/ic049236k
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“Atomic oxygen functionalization of vertically aligned carbon nanotubes”. Bittencourt C, Navio C, Nicolay A, Ruelle B, Godfroid T, Snyders R, Colomer J-F, Lagos MJ, Ke X, Van Tendeloo G, Suarez-Martinez I, Ewels CP, The journal of physical chemistry: C : nanomaterials and interfaces 115, 20412 (2011). http://doi.org/10.1021/jp2057699
Abstract: Vertically aligned multiwalled carbon nanotubes (v-MWCNTs) are functionalized using atomic oxygen generated in a microwave plasma. X-ray photoelectron spectroscopy depth profile analysis shows that the plasma treatment effectively grafts oxygen exclusively at the v-MWCNT tips. Electron microscopy shows that neither the vertical alignment nor the structure of v-MWCNTs were affected by the plasma treatment. Density functional calculations suggest assignment of XPS C 1s peaks at 286.6 and 287.5 eV, to epoxy and carbonyl functional groups, respectively.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.536
Times cited: 31
DOI: 10.1021/jp2057699
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“Indifference of superconductivity and magnetism to size-mismatched cations in the layered iron arsenides Ba1-xNaxFe2As2”. Cortes-Gil R, Parker DR, Pitcher MJ, Hadermann J, Clarke SJ, Chemistry of materials 22, 4304 (2010). http://doi.org/10.1021/cm100956k
Abstract: The evolution of the structure, magnetic ordering, and superconductivity in the series Ba(1-x)Na(x)Fe(2)As(2) is reported up to the limiting Na-rich composition with x = 0.6; the more Na-rich compositions are unstable at high temperatures with respect to competing phases. The magnetic and superconducting behaviors of the Bai,Na,Fe,As, members are similar to those of the betterinvestigated Ba(1-x)Na(x)Fe(2)As(2) analogues. This is evidently a consequence of the quantitatively similar evolution of the structure of the FeAs layers in the two series. In Ba(1-x)Na(x)Fe(2)As(2) antiferromagnetic order and an associated structural distortion are evident for x <= 0.35 and superconductivity is evident when x exceeds 0.2. For 0.4 <= x <= 0.6 bulk superconductivity is evident, and the long-range antiferromagnetically ordered state is completely suppressed. The maximum T(c) in the Ba(1-x)Na(x)Fe(2)As(2) series, as judged by the onset of diamagnetism, is 34K in Ba(0.6)Na(0.4)Fe(2)As(2). Despite the large mis-match in sizes between the two electropositive cations which separate the FeAs layers, there is no evidence for ordering of these cations on the length scale probed by electron diffraction.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 9.466
Times cited: 31
DOI: 10.1021/cm100956k
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“Synthesis and crystal structure of the Sr2Al1.07Mn0.93O5 brownmillerite”. Hadermann J, Abakumov AM, d' Hondt H, Kalyuzhnaya AS, Rozova MG, Markina MM, Mikheev MG, Tristan N, Klingeler R, Büchner B, Antipov EV, Journal of materials chemistry 17, 692 (2007). http://doi.org/10.1039/b614168d
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Times cited: 31
DOI: 10.1039/b614168d
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“Unprecedented shape selectivity in hydrogenation of triacylglycerol molecules with Pt/ZSM-5 zeolite”. Philippaerts A, Paulussen S, Breesch A, Turner S, Lebedev OI, Van Tendeloo G, Sels B, Jacobs P, Angewandte Chemie: international edition in English 50, 3947 (2011). http://doi.org/10.1002/anie.201007513
Abstract: Well tuned: ZSM-5 with platinum nanoparticles preferably hydrogenates trans fatty acids over cis isomers in model triacylglycerols for geometric reasons. The central fatty acid chain reacts faster, pointing to pore mouth adsorption in a tuning fork conformation (see picture). This conformation induces stepwise hydrogenation, resulting in fast removal of the unstable central triene, while formation of saturated chains is limited.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 11.994
Times cited: 31
DOI: 10.1002/anie.201007513
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“Gas-phase synthesis of Mg-Ti nanoparticles for solid-state hydrogen storage”. Calizzi M, Venturi F, Ponthieu M, Cuevas F, Morandi V, Perkisas T, Bals S, Pasquini L, Physical chemistry, chemical physics 18, 141 (2016). http://doi.org/10.1039/c5cp03092g
Abstract: Mg-Ti nanostructured samples with different Ti contents were prepared via compaction of nanoparticles grown by inert gas condensation with independent Mg and Ti vapour sources. The growth set-up offered the option to perform in situ hydrogen absorption before compaction. Structural and morphological characterisation was carried out by X-ray diffraction, energy dispersive spectroscopy and electron microscopy. The formation of an extended metastable solid solution of Ti in hcp Mg was detected up to 15 at% Ti in the as-grown nanoparticles, while after in situ hydrogen absorption, phase separation between MgH2 and TiH2 was observed. At a Ti content of 22 at%, a metastable Mg-Ti-H fcc phase was observed after in situ hydrogen absorption. The co-evaporation of Mg and Ti inhibited nanoparticle coalescence and crystallite growth in comparison with the evaporation of Mg only. In situ hydrogen absorption was beneficial to subsequent hydrogen behaviour, studied by high pressure differential scanning calorimetry and isothermal kinetics. A transformed fraction of 90% was reached within 100 s at 300 degrees C during both hydrogen absorption and desorption. The enthalpy of hydride formation was not observed to differ from bulk MgH2.
Keywords: A1 Journal article; Engineering Management (ENM); Electron microscopy for materials research (EMAT)
Impact Factor: 4.123
Times cited: 31
DOI: 10.1039/c5cp03092g
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“Phosphate ion functionalization of perovskite surfaces for enhanced oxygen evolution reaction”. Yang C, Laberty-Robert C, Batuk D, Cibin G, Chadwick AV, Pimenta V, Yin W, Zhang L, Tarascon J-M, Grimaud A, The journal of physical chemistry letters 8, 3466 (2017). http://doi.org/10.1021/ACS.JPCLETT.7B01504
Abstract: Recent findings revealed that surface oxygen can participate in the oxygen evolution reaction (OER) for the most active catalysts, which eventually triggers a new mechanism for which the deprotonation of surface intermediates limits the OER activity. We propose in this work a “dual strategy” in which tuning the electronic properties of the oxide, such as La1-xSrxCoO3-delta, can be dissociated from the use of surface functionalization with phosphate ion groups (P-i) that enhances the interfacial proton transfer. Results show that the P-i functionalized La0.5Sr0.5CoO3-delta gives rise to a significant enhancement of the OER activity when compared to La0.5Sr0.5Co3-delta and LaCoO3. We further demonstrate that the P-i surface functionalization selectivity enhances the activity when the OER kinetics is limited by the proton transfer. Finally, this work suggests that tuning the catalytic activity by such a “dual approach” may be a new and largely unexplored avenue for the design of novel high-performance catalysts.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 9.353
Times cited: 31
DOI: 10.1021/ACS.JPCLETT.7B01504
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“Electrochemical determination of hydrogen peroxide with cytochrome c peroxidase and horse heart cytochrome c entrapped in a gelatin hydrogel”. De Wael K, Bashir Q, van Vlierberghe S, Dubruel P, Heering HA, Adriaens A, Bioelectrochemistry: an international journal devoted to electrochemical aspects of biology and biological aspects of electrochemistry 83, 15 (2012). http://doi.org/10.1016/J.BIOELECHEM.2011.07.001
Abstract: A novel and versatile method, based on a membrane-free enzyme electrode in which both the enzyme and a mediator protein are entrapped in a gelatine hydrogel was developed for the fabrication of biosensors. As a proof of principle, we prepared a hydrogen peroxide biosensor by successfully entrapping both horse heart cytochrome c (HHC) and Saccharomyces cerevisae cytochrome c peroxidase (CCP) in a gelatin matrix which is immobilized on a gold electrode. This electrode was first pretreated with 6-mercaptohexanol. The biosensor displayed a rapid response and an expanded linear response range from 0 to 0.3 mM (R = 0.987) with a detection limit of 1 × 10− 5 M in a HEPES buffer solution (pH 7.0). This method of encapsulation is now further investigated for industrial biosensor applications.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 3.346
Times cited: 31
DOI: 10.1016/J.BIOELECHEM.2011.07.001
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“Electron microscopy of a family of hexagonal perovskites: one-dimensional structures related to Sr4Ni3O9”. Huvé, M, Renard C, Abraham F, Van Tendeloo G, Amelinckx S, Journal of solid state chemistry 135, 1 (1998). http://doi.org/10.1006/jssc.1997.7522
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.299
Times cited: 30
DOI: 10.1006/jssc.1997.7522
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“Electronic properties of graphene nano-flakes : energy gap, permanent dipole, termination effect, and Raman spectroscopy”. Singh SK, Neek-Amal M, Peeters FM, The journal of chemical physics 140, 074304 (2014). http://doi.org/10.1063/1.4865414
Abstract: The electronic properties of graphene nano-flakes (GNFs) with different edge passivation are investigated by using density functional theory. Passivation with F and H atoms is considered: C-Nc X-Nx (X = F or H). We studied GNFs with 10 < N-c < 56 and limit ourselves to the lowest energy configurations. We found that: (i) the energy difference Delta between the highest occupied molecular orbital and the lowest unoccupied molecular orbital decreases with N-c, (ii) topological defects (pentagon and heptagon) break the symmetry of the GNFs and enhance the electric polarization, (iii) the mutual interaction of bilayer GNFs can be understood by dipole-dipole interaction which were found sensitive to the relative orientation of the GNFs, (iv) the permanent dipoles depend on the edge terminated atom, while the energy gap is independent of it, and (v) the presence of heptagon and pentagon defects in the GNFs results in the largest difference between the energy of the spin-up and spin-down electrons which is larger for the H-passivated GNFs as compared to F-passivated GNFs. Our study shows clearly the effect of geometry, size, termination, and bilayer on the electronic properties of small GNFs. This study reveals important features of graphene nano-flakes which can be detected using Raman spectroscopy. (C) 2014 AIP Publishing LLC.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.965
Times cited: 30
DOI: 10.1063/1.4865414
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“Existence of superstructures due to large amounts of Fe vacancies in the LiFePO4-type framework”. Hamelet S, Casas-Cabanas M, Dupont L, Davoisne C, Tarascon JM, Masquelier C, Chemistry of materials 23, 32 (2011). http://doi.org/10.1021/cm102511m
Abstract: LiFePO4 has been under intense scrutiny over the past decade because it stands as an attractive positive electrode material for the next generation of Li-ion batteries to power electric vehicles and hybrid electric vehicles, hence the importance of its thermal behavior. The reactivity of LiFePO4 with air at moderate temperatures is shown to be dependent on its particle size. For nanosized materials, a progressive displacement of Fe from the core structure leading to a composite made of nanosize Fe2O3 and highly defective, oxidized LixFeyPO4 compositions, among which the “ideal” formula LiFe2/3PO4. Herein we report, from both temperature-controlled X-ray diffraction and electronic diffraction microscopy, that these off-stoichiometry olivine-type compounds show a defect ordering resulting in the formation of a superstructure. Such a finding shows striking similarities with the temperature-driven oxidation of fayalite Fe2SiO4 (another olivine) to structurally defective laihunite, reported in the literature three decades ago.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 9.466
Times cited: 30
DOI: 10.1021/cm102511m
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“Ferromagnetism and magnetoresistance in monolayered manganites Ca2-xLnxMnO4”. Maignan A, Martin C, Van Tendeloo G, Hervieu M, Raveau B, Journal of materials chemistry 8, 2411 (1998). http://doi.org/10.1039/a805393f
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Times cited: 30
DOI: 10.1039/a805393f
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“Ordered end-member of ZSM-48 zeolite family”. Kirschhock CEA, Liang D, Van Tendeloo G, Fécant A, Hastoye G, Vanbutsele G, Bats N, Guillon E, Martens JA, Chemistry of materials 21, 371 (2009). http://doi.org/10.1021/cm802614x
Abstract: ZSM-48 and related zeolites are considered to be highly disordered structures. Different polytypes can be clearly distinguished by simulation of high-resolution electron microscopy images. Synthesis of phase-pure polytypes was attempted. One of the investigated samples crystallized via seeding designated as COK-8 consisted of nanoscopic, needlelike crystals with a very large length/width ratio, growing along the pore direction. These specimens are phase-pure polytype 6 (PT6, numbering according to Lobo and van Koningsveld). Aggregates of these nanoneedles occasionally contained a second polytype: PT1. The latter polytype occurred more abundantly in larger crystal rods in an IZM-1 sample crystallized in ethylene glycol. Here too, the isolated crystallites mainly consist of large, defect-free regions of PT6. A simulation of polytype lattice energies offers a rational explanation for the observed polytypical intergrowth formation.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 9.466
Times cited: 30
DOI: 10.1021/cm802614x
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“Synthesis and structure of Bi14O20(SO4), a new bismuth oxide sulfate”. Francesconi MG, Kirbyshire AL, Greaves C, Richard O, Van Tendeloo G, Chem. mater. 10, 626 (1998). http://doi.org/10.1021/cm9706255
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 9.466
Times cited: 30
DOI: 10.1021/cm9706255
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“Gas phase photocatalytic spiral reactor for fast and efficient pollutant degradation”. Blommaerts N, Asapu R, Claes N, Bals S, Lenaerts S, Verbruggen SW, Chemical engineering journal 316, 850 (2017). http://doi.org/10.1016/j.cej.2017.02.038
Abstract: Photocatalytic reactors for the degradation of gaseous organic pollutants often suffer from major limitations such as small reaction area, sub-optimal irradiation conditions and thus limited reaction rate. In this work, an alternative solution is presented that involves a glass tube coated on the inside with (silvermodified) TiO2 and spiraled around a UVA lamp. First, the spiral reactor is coated from the inside with TiO2 using an experimentally verified procedure that is optimized toward UV light transmission. This procedure is kept as simple as possible and involves a single casting step of a 1 wt% suspension of TiO2 in ethanol through the spiral. This results in a coated tube that absorbs nearly all incident UV light under the experimental conditions used. The optimized coated spiral reactor is then benchmarked to a conventional annular photoreactor of the same outer dimensions and total catalyst loading over a broad range of experimental conditions. Although residence time distribution experiments indicate slightly longer dwelling of molecules in the spiral reactor, no significant difference in by-passing of gas between the spiral reactor and the annular reactor can be claimed. Acetaldehyde degradation efficiency of 100% is obtained with the spiral reactor for a residence time as low as 60 s, whereas the annular reactor could not achieve full degradation even at 1000 s residence time. In a final case study, addition of long-term stable silver nanoparticles, protected by an ultra-thin polymer shell applied via the layer-by-layer (LbL) method, to the spiral reactor coating is shown to double the degradation efficiency and provides an interesting strategy to cope with higher pollutant concentrations without changing the overall dimensions.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 6.216
Times cited: 30
DOI: 10.1016/j.cej.2017.02.038
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“Bottom-Up Mechanical Nanometrology of Granular Ag Nanoparticles Thin Films”. Benetti G, Caddeo C, Melis C, Ferrini G, Giannetti C, Winckelmans N, Bals S, J Van Bael M, Cavaliere E, Gavioli L, Banfi F, The journal of physical chemistry: C : nanomaterials and interfaces 121, 22434 (2017). http://doi.org/10.1021/acs.jpcc.7b05795
Abstract: Ultrathin metal nanoparticles coatings, synthesized by gas-phase deposition, are emerging as go-to materials in a variety of fields ranging from pathogens control, sensing to energy storage. Predicting their morphology and mechanical properties beyond a trial-and-error approach is a crucial issue limiting their exploitation in real-life applications. The morphology and mechanical properties of Ag nanoparticles ultrathin films, synthesized by supersonic cluster beam deposition, are here assessed adopting a bottom-up, multi-technique approach. A virtual film model is proposed merging high resolution scanning transmission electron microscopy, supersonic cluster beam dynamics and molecular dynamics simulations. The model is validated against mechanical nanometrology measurements and is readily extendable to metals other than Ag. The virtual film is shown to be a flexible and reliable predictive tool to access morphology-dependent properties such as mesoscale gas-dynamics and elasticity of ultrathin films synthesized by gas-phase deposition.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 4.536
Times cited: 30
DOI: 10.1021/acs.jpcc.7b05795
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“Study on the impregnation of archaeological waterlogged wood with consolidation treatments using synchrotron radiation microtomography”. Bugani S, Modugno F, Lucejko JJ, Giachi G, Cagno S, Cloetens P, Janssens K, Morselli L, Analytical and bioanalytical chemistry 395, 1977 (2009). http://doi.org/10.1007/S00216-009-3101-5
Abstract: In favourable conditions of low temperature and low oxygen concentration, archaeological waterlogged wooden artefacts, such as shipwrecks, can survive with a good state of preservation. Nevertheless, anaerobic bacteria can considerably degrade waterlogged wooden objects with a significant loss in polysaccharidic components. Due to these decay processes, wood porosity and water content increase under ageing. In such conditions, the conservation treatments of archaeological wooden artefacts often involve the replacement of water with substances which fill the cavities and help to prevent collapse and stress during drying. The treatments are very often expensive and technically difficult, and their effectiveness very much depends on the chemical and physical characteristics of the substances used for impregnation. Also important are the degree of cavity-filling, penetration depth and distribution in the structure of the wood. In this study, the distribution in wood cavities of some mixtures based on polyethylene glycols and colophony, used for the conservation of waterlogged archaeological wood, was investigated using synchrotron radiation X-ray computed microtomography (SR-A mu CT). This non-destructive imaging technique was useful for the study of the degraded waterlogged wood and enabled us to visualise the morphology of the wood and the distribution of the materials used in the wood treatments. The study has shown how deposition is strictly related to the dimension of the wooden cavities. The work is currently proceeding with the comparison of synchrotron observations with the data of the solutions viscosity and with those of the properties imparted to the wood by the treatments.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 3.431
Times cited: 30
DOI: 10.1007/S00216-009-3101-5
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“Analytic versus CFD approach for kinetic modeling of gas phase photocatalysis”. Verbruggen SW, Lenaerts S, Denys S, Chemical engineering journal 262, 1 (2015). http://doi.org/10.1016/J.CEJ.2014.09.041
Abstract: In this work two methods for determining the LangmuirHinshelwood kinetic parameters for a slit-shaped flat bed photocatalytic reactor are compared: an analytic mass transfer based model adapted from literature and a computational fluid dynamics (CFD) approach that was used in conjunction with a simplex optimization routine. Despite the differences between both approaches, similar values for the kinetic parameters and similar trends in terms of their UV intensity dependence were found. Using an effectiveness-NTU (number of transfer units) approach, the analytic mass transfer based method could quantify the relative contributions of the rate limiting steps through a reaction effectiveness parameter. The numeric CFD approach on the other hand could yield the two kinetic parameters that determine the photocatalytic reaction rate simultaneously. Furthermore, it proved to be more accurate as it accounts for the spatial variation of flow rate, reaction rate and concentrations at the surface of the photocatalyst. We elaborate this dual kinetic analysis with regard to the photocatalytic degradation of acetaldehyde in air over a silicon wafer coated with a layer of TiO2 P25 (Evonik) and study the usefulness and limitations of both strategies.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 6.216
Times cited: 30
DOI: 10.1016/J.CEJ.2014.09.041
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“Antiferroelectric (Pb,Bi)1-xFe1+xO3-y perovskites modulated by crystallographic shear planes”. Abakumov AM, Batuk D, Hadermann J, Rozova MG, Sheptyakov DV, Tsirlin AA, Niermann D, Waschowski F, Hemberger J, Van Tendeloo G, Antipov EV, Chemistry of materials 23, 255 (2011). http://doi.org/10.1021/cm102907h
Abstract: We demonstrate for the first time a possibility to vary the anion content in perovskites over a wide range through a long-range-ordered arrangement of crystallographic shear (CS) planes. Anion-deficient perovskites (Pb,Bi)1−xFe1+xO3−y with incommensurately modulated structures were prepared as single phases in the compositional range from Pb0.857Bi0.094Fe1.049O2.572 to Pb0.409Bi0.567Fe1.025O2.796. Using a combination of electron diffraction and high-resolution scanning transmission electron microscopy, we constructed a superspace model describing a periodic arrangement of the CS planes. The model was verified by refinement of the Pb0.64Bi0.32Fe1.04O2.675 crystal structure from neutron powder diffraction data ((3 + 1)D S.G. X2/m(α0γ), X = [1/2,1/2,1/2,1/2], a = 3.9082(1) Å, b = 3.90333(8) Å, c = 4.0900(1) Å, β = 91.936(2)°, q = 0.05013(4)a* + 0.09170(3)c* at T = 700 K, RP = 0.036, RwP = 0.048). The (Pb,Bi)1−xFe1+xO3−y structures consist of perovskite blocks separated by CS planes confined to nearly the (509)p perovskite plane. Along the CS planes, the perovskite blocks are shifted with respect to each other over the 1/2[110]p vector that transforms the corner-sharing connectivity of the FeO6 octahedra in the perovskite framework to an edge-sharing connectivity of the FeO5 pyramids at the CS plane, thus reducing the oxygen content. Variation of the chemical composition in the (Pb,Bi)1−xFe1+xO3−y series occurs mainly because of a changing thickness of the perovskite block between the interfaces, that can be expressed through the components of the q vector as Pb6γ+2αBi1−7γ−αFe1+γ−αO3−3γ−α. The Pb, Bi, and Fe atoms are subjected to strong displacements occurring in antiparallel directions on both sides of the perovskite blocks, resulting in an antiferroelectric-type structure. This is corroborated by the temperature-, frequency-, and field-dependent complex permittivity measurements. Pb0.64Bi0.32Fe1.04O2.675 demonstrates a remarkably high resistivity >0.1 T Ω cm at room temperature and orders antiferromagnetically below TN = 608(10) K.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 9.466
Times cited: 29
DOI: 10.1021/cm102907h
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