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“Improved multislice calculations for including higher-order Laue zones effects”. Lobato I, van Dyck D, Ultramicroscopy 119, 63 (2012). http://doi.org/10.1016/j.ultramic.2012.01.003
Abstract: A new method for including higher-order Laue zones (HOLZs) effects in an efficient way in electron scattering simulations has been developed and tested by detail calculations. The calculated results by the conventional multislice (CMS) method and the improved conventional multislice (ICMS) method using a large dynamical aperture to avoid numerical errors are compared with accurate results. We have found that the zero-order Laue zones (ZOLZs) reflection cannot be properly described only using the projected potential in the whole unit cell; in general, we need to subslice the electrostatic potential inside the unit cell. It is shown that the ICMS method has higher accuracy than the CMS method for the calculation of the ZOLZ, HOLZ and Pseudo-HOLZ reflections. Hence, ICMS method allows to use a larger slice thickness than the CMS method and reduces the calculation time. (C) 2012 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Impact Factor: 2.843
Times cited: 6
DOI: 10.1016/j.ultramic.2012.01.003
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“Ti4O7 supported Ru@Pt core–shell catalyst for CO-tolerance in PEM fuel cell hydrogen oxidation reaction”. L Zhang J Kim J Zhang F Nan N Gauquelin GA Botton P He R Bashyam S Knights, Applied Energy 103, 507 (2013). http://doi.org/10.1016/j.apenergy.2012.10.017
Abstract: A new method is developed for synthesizing Ti4O7 supported Ru@Pt core–shell catalyst (Ru@Pt/Ti4O7) through pyrolysis followed by microwave irradiation. The purpose is to improve the Ru durability of PtRu from core–shell structure and strong bonding to Ti4O7 oxide. In this method, the first step is to co-reduce the mixture of ruthenium precursor and TiO2 in a H2 reducing atmosphere under heat-treatment to obtain a Ru core on Ti4O7 support, and the second step is to create a shell of platinum via microwave irradiation. Energy dispersive X-ray spectrometry, X-ray Diffraction, High-resolution Scanning Transmission Electron Microscopy with the high-angle annular dark-field method and Electron Energy-Loss Spectroscopy are used to demonstrate that this catalyst with larger particles has a core–shell structure with a Ru core and a Pt shell. Electrochemical measurements show Ru@Pt/Ti4O7 catalyst has a higher CO-tolerance capability than that of PtRu/C alloy catalyst.
Keywords: A1 Journal Article; Electron Microscopy for Materials Science (EMAT) ;
Times cited: 33
DOI: 10.1016/j.apenergy.2012.10.017
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“Element Specific Atom Counting at the Atomic Scale by Combining High Angle Annular Dark Field Scanning Transmission Electron Microscopy and Energy Dispersive X‐ray Spectroscopy”. De Backer A, Zhang Z, van den Bos KHW, Bladt E, Sánchez‐Iglesias A, Liz‐Marzán LM, Nellist PD, Bals S, Van Aert S, Small methods , 2200875 (2022). http://doi.org/10.1002/smtd.202200875
Abstract: A new methodology is presented to count the number of atoms in multimetallic nanocrystals by combining energy dispersive X-ray spectroscopy (EDX) and high angle annular dark field scanning transmission electron microscopy (HAADF STEM). For this purpose, the existence of a linear relationship between the incoherent HAADF STEM and EDX images is exploited. Next to the number of atoms for each element in the atomic columns, the method also allows quantification of the error in the obtained number of atoms, which is of importance given the noisy nature of the acquired EDX signals. Using experimental images of an Au@Ag core–shell nanorod, it is demonstrated that 3D structural information can be extracted at the atomic scale. Furthermore, simulated data of an Au@Pt core–shell nanorod show the prospect to characterize heterogeneous nanostructures with adjacent atomic numbers.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 12.4
Times cited: 5
DOI: 10.1002/smtd.202200875
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“A new mixed-valence ferrite with a cubic structure, YBaFe4O7: spin-glass-like behavior”. Caignaert V, Abakumov AM, Pelloquin D, Pralong V, Maignan A, Van Tendeloo G, Raveau B, Chemistry of materials 21, 1116 (2009). http://doi.org/10.1021/cm803312f
Abstract: A new mixed-valence ferrite, YBaFe4O7, has been synthesized. Its unique cubic structure, with a = 8.9595(2) Å, is closely related to that of the hexagonal 114 oxides YBaCo4O7 and CaBaFe4O7. It consists of corner-sharing FeO4 tetrahedra, forming triangular and kagome layers parallel to (111)C. In fact, the YBaFe4O7 and CaBaFe4O7 structures can be described as two different ccc and chch close packings of [BaO3]∞ and [O4]∞ layers, respectively, whose tetrahedral cavities are occupied by Fe2+/Fe3+ cations. The local structure of YBaFe4O7 is characterized by a large amount of stacking faults originating from the presence of hexagonal layers in the ccc cubic close-packed YBaFe4O7 structure. In this way, they belong to the large family of spinels and hexagonal ferrites studied for their magnetic properties. Differently from all the ferrites and especially from CaBaFe4O7, which are ferrimagnetic, YBaFe4O7 is an insulating spin glass with Tg = 50 K.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 9.466
Times cited: 39
DOI: 10.1021/cm803312f
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“Self-Assembly of Pluronic F127—Silica Spherical Core–Shell Nanoparticles in Cubic Close-Packed Structures”. Kerkhofs S, Willhammar T, Van Den Noortgate H, Kirschhock CEA, Breynaert E, Van Tendeloo G, Bals S, Martens JA, Chemistry of materials 27, 5161 (2015). http://doi.org/10.1021/acs.chemmater.5b01772
Abstract: A new ordered mesoporous silica material (COK-19) with cubic symmetry is synthesized by silicate polycondensation in a citric acid/citrate buffered micellar solution of Pluronic F127 triblock copolymer near neutral pH. SAXS, nitrogen adsorption, TEM, and electron tomography reveal the final material has a cubic close packed symmetry (Fm3̅m) with isolated spherical mesopores interconnected through micropores. Heating of the synthesis medium from room temperature to 70 °C results in a mesopore size increase from 7.0 to 11.2 nm. Stepwise addition of the silicate source allows isolation of a sequence of intermediates that upon characterization with small-angle X-ray scattering uncovers the formation process via formation and aggregation of individual silica-covered Pluronic micelles.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 9.466
Times cited: 39
DOI: 10.1021/acs.chemmater.5b01772
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“Pb5Fe3TiO11Cl : a rare example of Ti(IV) in a square pyramidal oxygen coordination”. Batuk M, Batuk D, Abakumov AM, Hadermann J, Journal of solid state chemistry 215, 245 (2014). http://doi.org/10.1016/j.jssc.2014.04.002
Abstract: A new oxychloride Pb5Fe3TiO11Cl has been synthesized using the solid state method. Its crystal and magnetic structure was investigated in the 1.5550 K temperature range using electron diffraction, high angle annular dark field scanning transmission electron microscopy, atomic resolution energy dispersive X-ray spectroscopy, neutron and X-ray powder diffraction. At room temperature Pb5Fe3TiO11Cl crystallizes in the P4/mmm space group with the unit cell parameters a=3.91803(3) Å and c=19.3345(2) Å. Pb5Fe3TiO11Cl is a new n=4 member of the oxychloride perovskite-based homologous series An+1BnO3n−1Cl. The structure is built of truncated Pb3Fe3TiO11 quadruple perovskite blocks separated by CsCl-type Pb2Cl slabs. The perovskite blocks consist of two layers of (Fe,Ti)O6 octahedra sandwiched between two layers of (Fe,Ti)O5 square pyramids. The Ti4+ cations are preferentially located in the octahedral layers, however, the presence of a noticeable amount of Ti4+ in a five-fold coordination environment has been undoubtedly proven using neutron powder diffraction and atomic resolution compositional mapping. Pb5Fe3TiO11Cl is antiferromagnetically ordered below 450(10) K. The ordered Fe magnetic moments at 1.5 K are 4.06(4) μB and 3.86(5) μB on the octahedral and square-pyramidal sites, respectively.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.299
Times cited: 4
DOI: 10.1016/j.jssc.2014.04.002
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“Oxygen vacancy ordering in the double-layered Ruddlesden-Popper cobaltite Sm2BaCo2O7-\delta”. Gillie LJ, Hadermann J, Hervieu M, Maignan A, Martin C, Chemistry of materials 20, 6231 (2008). http://doi.org/10.1021/cm8010138
Abstract: A new oxygen-deficient Ruddlesden−Popper (RP) cobaltite Sm2BaCo2O7−δ (δ ≈ 1.0) has been synthesized and the crystal structure elucidated by Rietveld analysis of X-ray powder diffraction (XRD) data and transmission electron microscopy (TEM). The phase crystallizes in a primitive orthorhombic unit cell, with lattice parameters a = 5.4371(4) Å; b = 5.4405(4) Å and c = 19.8629(6) Å, and space group Pnnm. Contrary to other oxygen-deficient cobalt RP phases, the oxygen vacancies are located in the equatorial positions of the [CoO] layers to give an intralayer structure similar to Sr2Mn2O5, which is not usually observed for cobalt-containing materials. The Sm3+ and Ba2+ cations show a strong preference for distinct sites, with the majority of the larger Ba2+ cations situated in the perovskite block layers and Sm3+ cations predominantly in the rock salt layers. Magnetic susceptibility data demonstrate the strong antiferromagnetic (AFM) character of Sm2BaCo2O7−δ.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 9.466
Times cited: 7
DOI: 10.1021/cm8010138
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“New perovskite-based manganite Pb2Mn2O5”. Hadermann J, Abakumov AM, Perkisas T, d' Hondt H, Tan H, Verbeeck J, Filonenko VP, Antipov EV, Van Tendeloo G, Journal of solid state chemistry 183, 2190 (2010). http://doi.org/10.1016/j.jssc.2010.07.032
Abstract: A new perovskite based compound Pb2Mn2O5 has been synthesized using a high pressure high temperature technique. The structure model of Pb2Mn2O5 is proposed based on electron diffraction, high angle annular dark field scanning transmission electron microscopy and high resolution transmission electron microscopy. The compound crystallizes in an orthorhombic unit cell with parameters a=5.736(1)Å≈√2a p p p (a p the parameter of the perovskite subcell) and space group Pnma. The Pb2Mn2O5 structure consists of quasi two-dimensional perovskite blocks separated by 1/2[110] p (1̄01) p crystallographic shear planes. The blocks are connected to each other by chains of edge-sharing MnO5 distorted tetragonal pyramids. The chains of MnO5 pyramids and the MnO6 octahedra of the perovskite blocks delimit six-sided tunnels accommodating double chains of Pb atoms. The tunnels and pyramidal chains adopt two mirror-related configurations (left L and right R) and layers consisting of chains and tunnels of the same configuration alternate in the structure according to an -LRLR-sequence. The sequence is sometimes locally violated by the appearance of -LL- or -RR-fragments. A scheme is proposed with a JahnTeller distortion of the MnO6 octahedra with two long and two short bonds lying in the ac plane, along two perpendicular orientations within this plane, forming a d-type pattern.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.299
Times cited: 8
DOI: 10.1016/j.jssc.2010.07.032
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“Ordering of Pd2+ and Pd4+ in the mixed-valent palladate KPd2O3”. Panin RV, Khasanova NR, Bougerol C, Schnelle W, Van Tendeloo G, Antipov EV, Inorganic chemistry 49, 1295 (2010). http://doi.org/10.1021/ic902187a
Abstract: A new potassium palladate KPd2O3 was synthesized by the reaction of KO2 and PdO at elevated oxygen pressure. Its crystal structure was solved from powder X-ray diffraction data in the space group Rm (a = 6.0730(1) Å, c = 18.7770(7) Å, and Z = 6). KPd2O3 represents a new structure type, consisting of an alternating sequence of K+ and Pd2O3− layers with ordered Pd2+ and Pd4+ ions. The presence of palladium ions in di- and tetravalent low-spin states was confirmed by magnetic susceptibility measurements.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.857
Times cited: 9
DOI: 10.1021/ic902187a
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“Synthesis and structural characterization of a novel Sillén &ndash, Aurivillius bismuth oxyhalide, PbBi3VO7.5Cl, and its derivatives”. Charkin DO, Plokhikh IV, Kazakov SM, Kalmykov SN, Akinfiev VS, Gorbachev AV, Batuk M, Abakumov AM, Teterin YA, Maslakov KI, Teterin AY, Ivanov KE, Solid state sciences 75, 27 (2018). http://doi.org/10.1016/j.solidstatesciences.2017.11.006
Abstract: A new Sillen – Aurivillius family of layered bismuth oxyhalides has been designed and successfully constructed on the basis of PbBiO2X(X = halogen) synthetic perites and g-form of Bi2VO5.5 solid elec- trolyte. This demonstrates, for the first time, the ability of the latter to serve as a building block in construction of mixed-layer structures. The parent compound PbBi3VO7.5-dCl (d = 0.05) has been investigated by powder XRD, TEM, XPS methods and magnetic susceptibility measurements. An unexpected but important condition for the formation of the mixed-layer structure is partial (ca. 5%) reduction of VV into VIV which probably suppresses competitive formation of apatite-like Pb – Bi vanadates. This reduction also stabilizes the g polymorphic form of Bi2VO5.5 not only in the intergrowth structure, but in Bi2V1-xMxO5.5-y (M – Nb, Sb) solid solutions.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.811
Times cited: 1
DOI: 10.1016/j.solidstatesciences.2017.11.006
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“Novel MoVSbOx-type catalysts for selective isobutane oxidation”. Paul JS, Groothaert MH, Kirschhock CEA, Lebedev OI, Jacobs PA, Maier WF, Catalysis today
T2 –, 7th European Workshop Meeting on Selective Oxidation, AUG 31-SEP 04, 2003, Innsbruck, AUSTRIA 91-2, 265 (2004). http://doi.org/10.1016/j.cattod.2004.03.041
Abstract: A new sol-gel synthesis procedure is proposed for the preparation of MoVSbOx catalysts for the selective oxidation of isobutane. Physico-chemical characterization of the materials calcined at 400 degreesC, showed essentially amorphous catalysts, with long-range order. Increase of calcination temperature, however, resulted in the formation of small crystalline regions, confirmed through TEM. EPR measurements on the calcined samples pointed to the presence of isolated and magnetically interacting V(IV) species. The reported catalysts proved to be much more selective for partial oxidation compared to a literature reference catalyst. Furthermore, it is shown that this versatile synthesis recipe forms an excellent start for high-throughput and combinatorial studies. (C) 2004 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.636
Times cited: 12
DOI: 10.1016/j.cattod.2004.03.041
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“Lead-mercury-based superconductors –, the 1212-cuprate Pb0.7Hg0.3Sr2+xCa0.7Nd0.3-xCu2O7-\delta and the new oxycarbonate Pb0.7Hg0.3Sr4Cu2CO3O7”. Martin C, Hervieu M, Huvé, M, Michel C, Maignan A, Van Tendeloo G, Raveau B, Physica: C : superconductivity 222, 19 (1994). http://doi.org/10.1016/0921-4534(94)90109-0
Abstract: A new superconducting mercury oxycarbonate, Pb0.7Hg0.3Sr4Cu2CO3O7, has been synthesized. This tetragonal phase (a = 3.824 angstrom, c= 16.468 angstrom) consists of an intergrowth of two nonsuperconducting compounds, Sr2CuO2CO3 and Pb0.7Hg0.3Sr2CuO5. It exhibits after optimization a critical temperature of 70 K, with a sharp transition and a superconducting volume fraction of 50%. Its behavior can be compared to that of thallium oxycarbonates previously isolated. This study is completed by a reinvestigation of the 1212 cuprate of the system Hg-Pb-Sr-Ca-Nd-Cu. A superconducting phase with the 1212 structure, similar to that previously obtained but with a significantly different composition, Pb0.7Hg0.3Sr2+xCa0.7Nd0.3-xCu2O7, has been obtained, with a T(c onset) of 100 K. The behavior of the latter is compared with other lead-based 1212 cuprates.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 0.942
Times cited: 49
DOI: 10.1016/0921-4534(94)90109-0
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“A layered iron-rich 2234-type with a mixed valence of iron: the ferrimagnetic Tl-doped Fe2(Sr2-\varepsilonTl\varepsilon)Sr3Fe4O14.65”. Lepoittevin C, Malo S, Nguyen N, Hebert S, Van Tendeloo G, Hervieu M, Chemistry of materials 20, 6468 (2008). http://doi.org/10.1021/cm8014385
Abstract: A new Tl-doped strontium ferrite Fe2(Sr2-Tl)Sr3Fe4O14.65, with an original structure, has been synthesized and structurally characterized by powder X-ray diffraction and transmission electron microscopy. The TGA and Mssbauer studies evidence a mixed valence of iron. The structure exhibits a commensurate modulation, with a F-type subcell a ≈ b ≈ 5.4 Å (≈ ap√2), c ≈ 42 Å with a modulation vector q = αa* with α = 0.4. The supercell parameters have been refined as a= 27.1101(8) Å, b= 5.5187(2) Å and c= 42.0513(9) Å, in the space group Fmmm. The electron diffraction and electron microscopy data of this novel ferrite show that it can be described as a FeTl-2234-type structure corresponding to the intergrowth of a quadruple perovskite slice [(SrFeO2.8)4], with a complex rock salt related slice [Fe2(Sr2-Tl)O3.4]∞, built up of one double iron layer [Fe2O2.4] sandwiched between two [SrO] layers. The HRTEM images show that the oxygen atoms and vacancies are randomly distributed in the perovskite layers while the HAADF STEM images evidence the absence of Tl segregation in the matrix. Fe2(Sr2-Tl)Sr3Fe4O14.65 exhibits a very large value of χ (11emu/mol) at 5 K, which remains large at 400 K; the M(H) loop presents a shape characteristic of ferrimagnetism, with a large coercive field of 0.3 T. The value of magnetization saturates at 400 K at 0.68 μB/Fe. At 10 K, the value of magnetization reaches a maximum of 2 μB/Fe. The resistivity presents a semiconducting-like behavior, with ρ 800 Ω·cm at 300 K.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 9.466
Times cited: 8
DOI: 10.1021/cm8014385
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“Exit wave reconstruction from focal series of HRTEM images, single crystal XRD and total energy studies on SbxWO3+y (x\sim0.11)”. Klingstedt M, Sundberg M, Eriksson L, Haigh S, Kirkland A, Grüner D, de Backer A, Van Aert S, Tarasaki O, Zeitschrift für Kristallographie 227, 341 (2012). http://doi.org/10.1524/zkri.2012.1517
Abstract: A new tungsten bronze in the SbWO system has been prepared in a solid state reaction from Sb2O3, WO3 and W metal powder. The average structure was determined by single crystal X-ray diffraction. SbxWO3+y (x ∼ 0.11) crystallizes in the orthorhombic space group Pm21n (no. 31), a = 27.8135(9) Å, b = 7.3659(2) Å and c = 3.8672(1) Å. The structure belongs to the (n)-ITB class of intergrowth tungsten bronzes. It contains slabs of hexagonal channels formed by six WO6 octahedra. These slabs are separated by three layers of WO6 octahedra that are arranged in a WO3-type fashion. The WO6 octahedra share all vertices to build up a three-dimensional framework. The hexagonal channels are filled with Sb atoms to ∼80% and additional O atoms. The atoms are shifted out of the center of the channels. Exit-wave reconstruction of focal series of high resolution-transmission-electron-microscope (HRTEM) images combined with statistical paramäeter estimation techniques allowed to study local ordering in the channels. Sb atoms in neighbouring channels tend to be displaced in the same direction, which is in agreement with total energy calculations on ordered structure models, but the ratio of the occupation of the two possible Sb sites varies from channel to channel. The structure of SbxWO3+y exhibits pronounced local modulations.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.179
Times cited: 4
DOI: 10.1524/zkri.2012.1517
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“Progress and new advances in simulating electron microscopy datasets using MULTEM”. Lobato I, Van Aert S, Verbeeck J, Ultramicroscopy 168, 17 (2016). http://doi.org/10.1016/j.ultramic.2016.06.003
Abstract: A new version of the open source program MULTEM is presented here. It includes a graphical user interface, tapering truncation of the atomic potential, CPU multithreading functionality, single/double precision calculations, scanning transmission electron microscopy (STEM) simulations using experimental detector sensitivities, imaging STEM (ISTEM) simulations, energy filtered transmission electron microscopy (EFTEM) simulations, STEM electron energy loss spectroscopy (EELS) simulations along with other improvements in the algorithms. We also present a mixed channeling approach for the calculation of inelastic excitations, which allows one to considerably speed up time consuming EFTEM/STEM-EELS calculations.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.843
Times cited: 43
DOI: 10.1016/j.ultramic.2016.06.003
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“Single-step alcohol-free synthesis of coreshell nanoparticles of \gamma-casein micelles and silica”. Kerkhofs S, Leroux F, Allouche L, Mellaerts R, Jammaer J, Aerts A, Kirschhock CEA, Magusin PCMM, Taulelle F, Bals S, Van Tendeloo G, Martens JA;, RSC advances 4, 25650 (2014). http://doi.org/10.1039/C4RA03252G
Abstract: A new, single-step protocol for wrapping individual nanosized β-casein micelles with silica is presented. This biomolecule-friendly synthesis proceeds at low protein concentration at almost neutral pH, and makes use of sodium silicate instead of the common silicon alkoxides. This way, formation of potentially protein-denaturizing alcohols can be avoided. The pH of the citrate-buffered synthesis medium is close to the isoelectric point of β-casein, which favours micelle formation. A limited amount of sodium silicate is added to the protein micelle suspension, to form a thin silica coating around the β-casein micelles. The size distribution of the resulting proteinsilica structures was characterized using DLS and SAXS, as well as 1H NMR DOSY with a dedicated pulsed-field gradient cryo-probehead to cope with the low protein concentration. The degree of silica-condensation was investigated by 29Si MAS NMR, and the nanostructure was revealed by advanced electron microscopy techniques such as ESEM and HAADF-STEM. As indicated by the combined characterization results, a silica shell of 2 nm is formed around individual β-casein micelles giving rise to separate protein coresilica shell nanoparticles of 17 nm diameter. This alcohol-free method at mild temperature and pH is potentially suited for packing protein molecules into bio-compatible silica nanocapsules for a variety of applications in biosensing, therapeutic protein delivery and biocatalysis.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.108
Times cited: 3
DOI: 10.1039/C4RA03252G
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“N-doped ordered mesoporous carbons prepared by a two-step nanocasting strategy as highly active and selective electrocatalysts for the reduction of O2 to H2O2”. Sheng X, Daems N, Geboes B, Kurttepeli M, Bals S, Breugelmans T, Hubin A, Vankelecom IFJ, Pescarmona PP, Applied catalysis : B : environmental 176-177, 212 (2015). http://doi.org/10.1016/j.apcatb.2015.03.049
Abstract: A new, two-step nanocasting method was developed to prepare N-doped ordered mesoporous carbon (NOMC) electrocatalysts for the reduction of O2 to H2O2. Our strategy involves the sequential pyrolysis of two inexpensive and readily available N and C precursors, i.e. aniline and dihydroxynaphthalene (DHN), inside the pores of a SBA-15 hard silica template to obtain N-doped graphitic carbon materials with well-ordered pores and high surface areas (764 and 877 m2g−1). By tuning the ratio of carbon sources to silica template, it was possible to achieve an optimal filling of the pores of the SBA-15 silica and to minimise carbon species outside the pores. These NOMC materials displayed outstanding electrocatalytic activity in the oxygen reduction reaction, achieving a remarkably enhanced kinetic current density compared to state-of-the-art N-doped carbon materials (−16.7 mA cm−2 at −0.35 V vs. Ag/AgCl in a 0.1 M KOH solution as electrolyte). The NOMC electrocatalysts showed high selectivity toward the two-electron reduction of oxygen to hydrogen peroxide and excellent long-term stability.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Applied Electrochemistry & Catalysis (ELCAT)
Impact Factor: 9.446
Times cited: 111
DOI: 10.1016/j.apcatb.2015.03.049
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“Measurement of specimen thickness by phase change determination in TEM”. Croitoru MD, van Dyck D, Liu YZ, Zhang Z, Ultramicroscopy 108, 1616 (2008). http://doi.org/10.1016/j.ultramic.2008.06.002
Abstract: A non-destructive method for measuring the thickness of thin amorphous films composed of light elements has been developed. The method employs the statistics of the phase of the electron exit wave function. The accuracy of this method has been checked numerically by the multislice method and compared with that based on the mean inner potential.
Keywords: A1 Journal article; Condensed Matter Theory (CMT); Electron microscopy for materials research (EMAT); Vision lab
Impact Factor: 2.843
Times cited: 2
DOI: 10.1016/j.ultramic.2008.06.002
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“Ba-3(Cr0.97(1)Te0.03(1))(2)TeO9: in Search of Jahn-Teller Distorted Cr(II) Oxide”. Li M-R, Deng Z, Lapidus SH, Stephens PW, Segre CU, Croft M, Sena RP, Hadermann J, Walker D, Greenblatt M, Inorganic chemistry 55, 10135 (2016). http://doi.org/10.1021/ACS.INORGCHEM.6B01047
Abstract: A novel 6H-type hexagonal perovskite Ba-3(Cr0.97(1)Te0.03(1))(2)TeO9 was prepared at high pressure (6 GPa) and temperature (1773 K). Both transmission electron microscopy and synchrotron powder X-ray diffraction data demonstrate that Ba-3(Cr0.97(1)Te0.03(1))(2)TeO9 crystallizes in P6(3)/mmc with face-shared (Cr0.97(1)Te0.03(1))O-6 octahedral pairs interconnected with TeO6 octahedra via corner-sharing. Structure analysis shows a mixed Cr2+/Cr3+ valence state with similar to 10% Cr2+. The existence of Cr2+ in Ba-3(Cr0.10(1)2+Cr0.87(1)3+Te0.036+)(2)TeO9 is further evidenced by X-ray absorption near-edge spectroscopy. Magnetic properties measurements show a paramagnetic response down to 4 K and a small glassy-state curvature at low temperature. In this work, the octahedral Cr2+O6 component is stabilized in an oxide material for the first time; the expected Jahn-Teller distortion of high-spin (d(4)) Cr2+ is not found, which is attributed to the small proportion of Cr2+ (similar to 10%) and the face-sharing arrangement of CrO6 octahedral pairs, which structurally disfavor axial distortion.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.857
Times cited: 2
DOI: 10.1021/ACS.INORGCHEM.6B01047
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“{110}-Layered B-cation ordering in the anion-deficient perovskite Pb2.4Ba2.6Fe2Sc2TiO13 with the crystallographic shear structure”. Tyablikov OA, Batuk D, Tsirlin AA, Batuk M, Verchenko VY, Filimonov DS, Pokholok KV, Sheptyakov DV, Rozova MG, Hadermann J, Antipov EV, Abakumov AM;, Journal of the Chemical Society : Dalton transactions 44, 10753 (2015). http://doi.org/10.1039/c4dt03867c
Abstract: A novel anion-deficient perovskite-based compound, Pb2.4Ba2.6Fe2Sc2TiO13, was synthesized via the citrate-based route. This compound is an n = 5 member of the A(n)B(n)O(3n-2) homologous series with unit-cell parameters related to the perovskite subcell a(p) approximate to 4.0 angstrom as a(p)root 2 x a(p) x 5a(p)root 2. The crystal structure of Pb2.4Ba2.6Fe2Sc2TiO13 consists of quasi-2D perovskite blocks with a thickness of three octahedral layers separated by the 1/2[110]((1) over bar 01)(p) crystallographic shear (CS) planes, which are parallel to the {110} plane of the perovskite subcell. The CS planes transform the corner-sharing octahedra into chains of edge-sharing distorted tetragonal pyramids. Using a combination of neutron powder diffraction, Fe-57 Mossbauer spectroscopy and atomic resolution electron energy-loss spectroscopy we demonstrate that the B-cations in Pb2.4Ba2.6Fe2Sc2TiO13 are ordered along the {110} perovskite layers with Fe3+ in distorted tetragonal pyramids along the CS planes, Ti4+ preferentially in the central octahedra of the perovskite blocks and Sc3+ in the outer octahedra of the perovskite blocks. Magnetic susceptibility and Mossbauer spectroscopy indicate a broadened magnetic transition around T-N similar to 45 K and the onset of local magnetic fields at low temperatures. The magnetic order is probably reminiscent of that in other A(n)B(n)O(3n-2) homologues, where G-type AFM order within the perovskite blocks has been observed.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.029
Times cited: 1
DOI: 10.1039/c4dt03867c
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“Novel class of nanostructured metallic glass films with superior and tunable mechanical properties”. Ghidelli M, Orekhov A, Bassi AL, Terraneo G, Djemia P, Abadias G, Nord M, Béché, A, Gauquelin N, Verbeeck J, Raskin J-p, Schryvers D, Pardoen T, Idrissi H, Acta Materialia , 116955 (2021). http://doi.org/10.1016/j.actamat.2021.116955
Abstract: A novel class of nanostructured Zr50Cu50 (%at.) metallic glass films with superior and tunable mechanical
properties is produced by pulsed laser deposition. The process can be controlled to synthetize a wide
range of film microstructures including dense fully amorphous, amorphous embedded with nanocrystals
and amorphous nano-granular. A unique dense self-assembled nano-laminated atomic arrangement
characterized by alternating Cu-rich and Zr/O-rich nanolayers with different local chemical enrichment
and amorphous or amorphous-crystalline composite nanostructure has been discovered, while
significant in-plane clustering is reported for films synthetized at high deposition pressures. This unique
nanoarchitecture is at the basis of superior mechanical properties including large hardness and elastic
modulus up to 10 and 140 GPa, respectively and outstanding total elongation to failure (>9%), leading to
excellent strength/ductility balance, which can be tuned by playing with the film architecture. These
results pave the way to the synthesis of novel class of engineered nanostructured metallic glass films
with high structural performances attractive for a number of applications in microelectronics and
coating industry.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 5.301
Times cited: 27
DOI: 10.1016/j.actamat.2021.116955
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“Accurate infrared absorption measurement of interstitial and precipitated oxygen in p+ silicon wafers”. De Gryse O, Clauws P, Rossou L, van Landuyt J, Vanhellemont J, Microelectronic engineering 45, 277 (1999). http://doi.org/10.1016/S0167-9317(99)00180-X
Abstract: A novel infrared absorption method has been developed to measure [he interstitial oxygen concentration in highly doped silicon. Thin samples of the order of 10-30 mu m are prepared in an essentially stress-free state without changing the state of the crystal. The oxygen concentration is then determined by measuring the height of the 1136-cm(-1) absorption peak due to interstitial oxygen at 5.5 K. The obtained results on as-grown samples are compared with those from gas fusion analysis. The precipitated oxygen concentration in annealed samples is also determined with the new method. It will be shown that the interstitial oxygen concentration in highly doped silicon can be determined with high accuracy and down to concentrations of 10(17) cm(-3). (C) 1999 Elsevier Science B.V. All rights reserved.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 1.806
DOI: 10.1016/S0167-9317(99)00180-X
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“LiZnNb4O11.5 : a novel oxygen deficient compound in the Nb-rich part of the Li2O-ZnO-Nb2O5 system”. Morozov VA, Arakcheeva AV, Konovalova VV, Pattison P, Chapuis G, Lebedev OI, Fomichev VV, Van Tendeloo G, Journal of solid state chemistry 183, 408 (2010). http://doi.org/10.1016/j.jssc.2009.12.008
Abstract: A novel lithium zinc niobium oxide LiZnNb(4)O(11.5) (LZNO) has been found in the Nb-rich part of Li(2)O-ZnO-Nb(2)O(5) system. LZNO, with an original alpha-PbO(2) related structure, has been synthesized by the routine ceramic technique and characterized by X-ray diffraction and transmission electron microscopy (TEM). Reflections belonging to the LZNO phase, observed in X-ray powder diffraction (XRPD) and electron diffraction, have been indexed as monoclinic with unit cell parameters a=17.8358(9)angstrom, b=15.2924(7)angstrom, c=5.0363(3)angstrom and gamma=96.607(5)degrees or as alpha-PbO(2)-like with lattice constants a=4.72420(3)angstrom, b=5.72780(3)angstrom, c=5.03320(3)angstrom, gamma=90.048(16)degrees and modulation vector q=0.3a*+1.1b* indicating a commensurately modulated alpha-PbO(2) related structure. The monoclinic cell is a supercell related to the latter. Using synchrotron powder diffraction data, the structure has been solved and refined as a commensurate modulation (superspace group P112(1)/n(alpha beta 0)00) as well as a supercell (space group P2(1)/b). The superspace description allows us to consider the LZNO structure as a member of the proposed alpha-PbO(2)-Z (3 + 1)D structure type, which unifies both incommensurately and commensurately modulated structures. HRTEM reveals several types of defects in LZNO and structural models for these defects are proposed. Two new phases in Li(2)O-ZnO-Nb(2)O(5) system are predicted on the basis of this detailed HRTEM analysis. (C) 2009 Elsevier Inc. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.299
Times cited: 9
DOI: 10.1016/j.jssc.2009.12.008
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“AVPO4F (A = Li, K): A 4 V Cathode Material for High-Power Rechargeable Batteries”. Fedotov SS, Khasanova NR, Samarin AS, Drozhzhin OA, Batuk D, Karakulina OM, Hadermann J, Abakumov AM, Antipov EV, Chemistry of materials 28, 411 (2016). http://doi.org/10.1021/acs.chemmater.5b04065
Abstract: A novel potassium-based fluoride-phosphate, KVPO4F, with a KTiOPO4 (KTP) type structure is synthesized and characterized. About 85% of potassium has been electrochemically extracted on oxidation producing a cathode material with attractive performance for Li-ion batteries. The material operates at the electrode potential near 4V vs Li/Li+ exhibiting a sloping voltage profile, extremely low polarization, small volume change of about 2% and excellent rate capability, maintaining more than 75% of the initial capacity at 40C discharge rate without significant fading.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 9.466
Times cited: 46
DOI: 10.1021/acs.chemmater.5b04065
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“Mixed-valent, heteroleptic homometallic diketonates as templates for the design of volatile heterometallic precursors”. Lieberman CM, Filatov AS, Wei Z, Rogachev AY, Abakumov AM, Dikarev EV, Chemical science 6, 2835 (2015). http://doi.org/10.1039/c4sc04002c
Abstract: A novel series of mixed-valent, heteroleptic transition metal diketonates that can be utilized as prospective single-source precursors for the low-temperature preparation of oxide materials are reported. The first mixed-valent iron beta-diketonates with different Fe-III/Fe-II ratios have been synthesized by applying the mixed-ligand approach. Based on nearly quantitative reaction yields and analysis of iron-oxygen bonds, these compounds were formulated as [Fe-III(acac)(3)][Fe-II(hfac)(2)] (1) and [Fe-II(hfac)(2)][Fe-III(acac)(3)][Fe-II(hfac)(2)] (2). In the above heteroleptic complexes, the Lewis acidic, coordinatively unsaturated Fe-II centers chelated by two hfac (hexafluoroacetylacetonate) ligands with electron-withdrawing substituents maintain bridging interactions with oxygen atoms of electron-donating acac (acetylacetonate) groups that chelate the neighboring Fe-III atoms. Switching the ligands on Fe-III and Fe-II atoms in starting reagents resulted in the instant ligand exchange between iron centers and in yet another polynuclear homometallic diketonate [Fe-II(hfac)(2)][Fe-III(acac)(2)(hfac)][Fe-II(hfac)(2)] (3) that adheres to the same bonding pattern as in complexes 1 and 2. The proposed synthetic methodology has been extended to design heterometallic diketonates with different M : M' ratios. Homometallic parent molecules have been used as templates to obtain heterometallic mixed-valent [Fe-III(acac)(3)][Mn-II(hfac)(2)] (4) and [Ni-II(hfac)(2)] – [Fe-III(acac)(3)][Ni-II(hfac)(2)] (5) complexes. The combination of two different diketonate ligands with electron-donating and electron-withdrawing substituents was found to be crucial for maintaining the above mixed-valent heterometallic assemblies. Theoretical investigation of two possible “isomers”, [Fe-III(acac)(3)][Mn-II(hfac)(2)] (4) and [Mn-III(acac)(3)][Fe-II(hfac)(2)] (40) provided an additional support for the metal site assignment giving a preference of 9.78 kcal mol(-1) for the molecule 4. Heterometallic complexes obtained in the course of this study have been found to act as effective single-source precursors for the synthesis of mixed-transition metal oxide materials MxM2-xO3 and MxMi-xO. The title highly volatile precursors can be used for the low-temperature preparation of both amorphous and crystalline heterometallic oxides in the form of thin films or nanosized particles that are known to operate as efficient catalysts in oxygen evolution reaction.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 8.668
Times cited: 13
DOI: 10.1039/c4sc04002c
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“Heterometallic molecular complexes act as messenger building units to encode desired metal-atom combinations to multivariate metal-organic frameworks”. Lopez-Garcia C, Canossa S, Hadermann J, Gorni G, Oropeza FE, de la Pena O'Shea VA, Iglesias M, Monge MA, Gutierrez-Puebla E, Gandara F, Journal of the American Chemical Society 144, 16262 (2022). http://doi.org/10.1021/JACS.2C06142
Abstract: A novel synthetic approach is described for the targeted preparation of multivariate metal-organic frameworks (MTV-MOFs) with specific combinations of metal elements. This methodology is based on the use of molecular complexes that already comprise desired metal-atom combinations, as building units for the MTV-MOF synthesis. These units are transformed into the MOF structural constituents through a ligand/linker exchange process that involves structural modifications while preserving their origina l l y encoded atomic combination. Thus, through the use of heterometalli c ring-shaped molecules combining gallium and nickel or cobalt, we have obtained MOFs with identical combinations of the metal elements, now incorporated in the rod-shaped secondary building unit, as confirmed with a combination of X-ray and electron diffraction, electron microscopy, and X-ray absorption spectroscopy techniques.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 15
DOI: 10.1021/JACS.2C06142
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“Triple ion beam cutting of diamond/Al composites for interface characterization”. Ji G, Tan Z, Shabadi R, Li Z, Grünewald W, Addad A, Schryvers D, Zhang D, Materials characterization 89, 132 (2014). http://doi.org/10.1016/j.matchar.2014.01.008
Abstract: A novel triple ion beam cutting technique was employed to prepare high-quality surfaces of diamond/Al composites for interfacial characterization, which has been unachievable so far. Near-perfect and artifact-free surfaces were obtained without mechanical pre-polishing. Hence, the as-prepared surfaces are readily available for further study and also, ready to be employed in a focus ion beam system for preferential selection of transmission electron microscopy samples. Dramatically different diamond/Al interface configurations – sub-micrometer Al2O3 particles and clean interfaces were unambiguously revealed.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.714
Times cited: 9
DOI: 10.1016/j.matchar.2014.01.008
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“Double moiré, with a twist : supermoiré, in encapsulated graphene”. Andelkovic M, Milovanović, SP, Covaci L, Peeters FM, Nano Letters 20, 979 (2020). http://doi.org/10.1021/ACS.NANOLETT.9B04058
Abstract: A periodic spatial modulation, as created by a moire pattern, has been extensively studied with the view to engineer and tune the properties of graphene. Graphene encapsulated by hexagonal boron nitride (hBN) when slightly misaligned with the top and bottom hBN layers experiences two interfering moire patterns, resulting in a so-called supermoire (SM). This leads to a lattice and electronic spectrum reconstruction. A geometrical construction of the nonrelaxed SM patterns allows us to indicate qualitatively the induced changes in the electronic properties and to locate the SM features in the density of states and in the conductivity. To emphasize the effect of lattice relaxation, we report band gaps at all Dirac-like points in the hole doped part of the reconstructed spectrum, which are expected to be enhanced when including interaction effects. Our result is able to distinguish effects due to lattice relaxation and due to the interfering SM and provides a clear picture on the origin of recently experimentally observed effects in such trilayer heterostuctures.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
Impact Factor: 10.8
Times cited: 48
DOI: 10.1021/ACS.NANOLETT.9B04058
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“Rational synthesis of F-doped iron oxides on Al2O3(0001) single crystals”. Carraro G, Gasparotto A, Maccato C, Bontempi E, Lebedev OI, Sada C, Turner S, Van Tendeloo G, Barreca D, RSC advances 4, 52140 (2014). http://doi.org/10.1039/c4ra09021g
Abstract: A plasma enhanced-chemical vapor deposition (PE-CVD) route to Fe2O3-based materials on Al2O3(0001) single crystals at moderate growth temperatures (200-400 degrees C) is reported. The use of the fluorinated Fe(hfa)(2)TMEDA (hfa = 1,1,1,5,5,5-hexafluoro-2,4-pentanedionate; TMEDA = N,N,N',N'-tetramethylethylenediamine) molecular precursor in Ar/O-2 plasmas enabled an in situ F-doping of iron oxide matrices, with a fluorine content tunable as a function of the adopted preparative conditions. Variations of the thermal energy supply enabled control of the system phase composition, resulting in gamma-Fe2O3 at 200 degrees C and alpha-Fe2O3 nanostructures at higher deposition temperatures. Notably, at 400 degrees C the formation of highly oriented alpha-Fe2O3 nanocolumns characterized by an epitaxial relation with the Al2O3(0001) substrate was observed. Beside fluorine content, phase composition and nano-organization, even the system optical properties and, in particular, energy gap values, could be tailored by proper modifications of processing parameters.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.108
Times cited: 4
DOI: 10.1039/c4ra09021g
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“Rational synthesis of F-doped iron oxides on Al2O3(0001) single crystals”. Carraro G, Gasparotto A, Maccato C, Bontempi E, Lebedev OI, Sada C, Turner S, Van Tendeloo G, Barreca D, Rsc Advances , 52140 (2014). http://doi.org/10.1039/C4RA09021G
Abstract: A plasma enhanced-chemical vapor deposition (PE-CVD) route to Fe2O3-based materials on Al2O3(0001) single crystals at moderate growth temperatures (200400 °C) is reported. The use of the fluorinated Fe(hfa)2TMEDA (hfa = 1,1,1,5,5,5-hexafluoro-2,4-pentanedionate; TMEDA = N,N,N′,N′-tetramethylethylenediamine) molecular precursor in Ar/O2 plasmas enabled an in situ F-doping of iron oxide matrices, with a fluorine content tunable as a function of the adopted preparative conditions. Variations of the thermal energy supply enabled control of the system phase composition, resulting in γ-Fe2O3 at 200 °C and α-Fe2O3 nanostructures at higher deposition temperatures. Notably, at 400 °C the formation of highly oriented α-Fe2O3 nanocolumns characterized by an epitaxial relation with the Al2O3(0001) substrate was observed. Beside fluorine content, phase composition and nano-organization, even the system optical properties and, in particular, energy gap values, could be tailored by proper modifications of processing parameters.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.108
Times cited: 4
DOI: 10.1039/C4RA09021G
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