“Highly-translucent, strong and aging-resistant 3Y-TZP ceramics for dental restoration by grain boundary segregation”. Zhang F, Vanmeensel K, Batuk M, Hadermann J, Inokoshi M, Van Meerbeek B, Naert I, Vleugels J, Acta biomaterialia 16, 215 (2015). http://doi.org/10.1016/j.actbio.2015.01.037
Abstract: Latest trends in dental restorative ceramics involve the development of full-contour 3Y-TZP ceramics which can avoid chipping of veneering porcelains. Among the challenges are the low translucency and the hydrothermal stability of 3Y-TZP ceramics. In this work, different trivalent oxides (Al2O3, Sc2O3, Nd2O3 and La2O3) were selected to dope 3Y-TZP ceramics. Results show that dopant segregation was a key factor to design hydrothermally stable and high-translucent 3Y-TZP ceramics and the cation dopant radius could be used as a controlling parameter. A large trivalent dopant, oversized as compared to Zr4+, exhibiting strong segregation at the ZrO2 grain boundary was preferred. The introduction of 0.2 mol% La2O3 in conventional 0.10.25 wt.% Al2O3-doped 3Y-TZP resulted in an excellent combination of high translucency and superior hydrothermal stability, while retaining excellent mechanical properties.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 6.319
Times cited: 54
DOI: 10.1016/j.actbio.2015.01.037
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“Octahedral-shaped perovskite nanocrystals and their visible-light photocatalytic activity”. Yin S, Tian H, Ren Z, Wei X, Chao C, Pei J, Li X, Xu G, Shen G, Han G, Chemical communications 50, 6027 (2014). http://doi.org/10.1039/c4cc01118j
Abstract: Octahedral-shaped perovskite PbTiO3 nanocrystals (PT OCT) with well-defined {111} facets exposed have been successfully synthesized via a facile hydrothermal method by using LiNO3 as an ion surfactant. The Li-O bond on the surface of PT OCT nanocrystals is essential to the stability of such nanocrystals and also results in a dramatic high visible-light photocatalytic activity.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 6.319
Times cited: 19
DOI: 10.1039/c4cc01118j
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“Positive graphene by chemical design : tuning supramolecular strategies for functional surfaces”. Hadad C, Ke X, Carraro M, Sartorel A, Bittencourt C, Van Tendeloo G, Bonchio M, Quintana M, Prato M, Chemical communications 50, 885 (2014). http://doi.org/10.1039/c3cc47056c
Abstract: A diazonium based-arylation reaction was efficiently used for the covalent addition of 4-amino-N,N,N-trimethylbenzene ammonium to stable dispersions of few layer graphene (FLG) yielding an innovative FLG platform with positive charges to immobilize inorganic polyanions.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 6.319
Times cited: 19
DOI: 10.1039/c3cc47056c
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“A protecting group approach toward synthesis of Au-silica Janus nanostars”. Rodríguez-Fernández D, Altantzis T, Heidari H, Bals S, Liz-Marzan LM, Chemical communications 50, 79 (2014). http://doi.org/10.1039/c3cc47531j
Abstract: The concept of protecting groups, widely used in organic chemistry, has been applied for the synthesis of Au-silica Janus stars, in which gold branches protrude from one half of Au-silica Janus spheres. This configuration opens up new possibilities to apply the plasmonic properties of gold nanostars, as well as a variety of chemical functionalizations on the silica component.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 6.319
Times cited: 26
DOI: 10.1039/c3cc47531j
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“Lewis base mediated efficient synthesis and solvation-like host-guest chemistry of covalent organic framework-1”. Kalidindi SB, Wiktor C, Ramakrishnan A, Weßing J, Schneemann A, Van Tendeloo G, Fischer RA, Chemical communications 49, 463 (2013). http://doi.org/10.1039/c2cc37183a
Abstract: N-Lewis base mediated room temperature synthesis of covalent organic frameworks (COFs) starting from a solution of building blocks instead of partially soluble building blocks was developed. This protocol shifts COF synthetic chemistry from sealed tubes to open beakers. Non-conventional inclusion compounds of COF-1 were obtained by vapor phase infiltration of ferrocene and azobenzene, and solvation like effects were established.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 6.319
Times cited: 17
DOI: 10.1039/c2cc37183a
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“Production of large graphene sheets by exfoliation of graphite under high power ultrasound in the presence of tiopronin”. Quintana M, Grzelczak M, Spyrou K, Kooi B, Bals S, Van Tendeloo G, Rudolf P, Prato M, Chemical communications 48, 12159 (2012). http://doi.org/10.1039/c2cc35298b
Abstract: Under ultrasonication, the production of high quality graphene layers by exfoliation of graphite was achieved via addition of tiopronin as an antioxidant.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 6.319
Times cited: 39
DOI: 10.1039/c2cc35298b
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“Selective organic functionalization of graphene bulk or graphene edges”. Quintana M, Montellano A, Esau del Rio Castillo A, Van Tendeloo G, Bittencourt C, Prato M, Chemical communications 47, 9330 (2011). http://doi.org/10.1039/c1cc13254g
Abstract: Graphene sheets have been functionalized with a PAMAM dendron, finding that graphene can be efficiently functionalized all over the surface, or only at the edges, depending on the reactions used in the functionalization process.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 6.319
Times cited: 84
DOI: 10.1039/c1cc13254g
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“Stability of Ni in nitinol oxide surfaces”. Tian H, Schryvers D, Liu D, Jiang Q, van Humbeeck J, Acta biomaterialia 7, 892 (2011). http://doi.org/10.1016/j.actbio.2010.09.009
Abstract: The stability of Ni in titanium oxide surface layers on nitinol wires known to release certain amounts of Ni was investigated by first principles density functional theory and transmission electron microscopy. The oxides were identified as a combination of TiO and TiO2 depending on the thickness of the layer. The calculations indicate that free Ni atoms can exist in TiO at ambient temperature while Ni particles form in TiO2, which was confirmed by the transmission electron microscopy observations. The results are discussed with respect to surface stability and Ni release due to free Ni atoms and Ni particles.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 6.319
Times cited: 39
DOI: 10.1016/j.actbio.2010.09.009
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“Molecular sieve properties of mesoporous silica with intraporous nanocarbon”. de Clippel F, Harkiolakis A, Ke X, Vosch T, Van Tendeloo G, Baron GV, Jacobs PA, Denayer JFM, Sels BF, Chemical communications 46, 928 (2010). http://doi.org/10.1039/b918864a
Abstract: Biporous carbonsilica materials (CSM) with molecular sieve properties and high sorption capacity were developed by synthesizing nano-sized carbon crystallites in the mesopores of Al-MCM-41.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 6.319
Times cited: 21
DOI: 10.1039/b918864a
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“Synthesis of highly stable pure-silica thin-walled hexagonally ordered mesoporous material”. Verlooy P, Aerts A, Lebedev OI, Van Tendeloo G, Kirschhock C, Martens JA, Chemical communications , 4287 (2009). http://doi.org/10.1039/b901796h
Abstract: Hexagonally ordered mesoporous silica with a very narrow mesopore size distribution and exceptionally high stability paired with unusually thin pore walls was prepared using piperidine and cetyltrimethylammonium bromide.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 6.319
Times cited: 17
DOI: 10.1039/b901796h
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“Bundles of identical double-walled carbon nanotubes”. Colomer J-F, Henrard L, Launois P, Van Tendeloo G, Lucas AA, Lambin P, Chemical communications , 2592 (2004). http://doi.org/10.1039/b410930a
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 6.319
Times cited: 13
DOI: 10.1039/b410930a
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“Post-synthesis deposition of V-Zeolitic nanoparticles in SBA-15”. Meynen V, Beyers E, Cool P, Vansant EF, Mertens M, Weyten H, Lebedev OI, Van Tendeloo G, Chemical communications , 898 (2004). http://doi.org/10.1039/b400636d
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA)
Impact Factor: 6.319
Times cited: 22
DOI: 10.1039/b400636d
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“Synthesis of single wall carbon nanotubes by catalytic decomposition of hydrocarbons”. Colomer J-F, Bister G, Willems I, Konya Z, Fonseca A, Van Tendeloo G, Nagy JB, Chemical communications , 1343 (1999). http://doi.org/10.1039/a903142a
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 6.319
Times cited: 110
DOI: 10.1039/a903142a
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“Janus Gold Nanoparticles Obtained via Spontaneous Binary Polymer Shell Segregation”. Percebom AMM, Giner-casares JJ, Claes N, Bals S, Loh W, Liz-Marzan LM, Chemical communications 52, 4278 (2016). http://doi.org/10.1039/C5CC10454H
Abstract: Janus gold nanoparticles are of high interest because they allow directed self-assembly and display plasmonic properties. We succeeded in coating gold nanoparticles with two different polymers that form a Janus shell. The spontaneous segregation of two immiscible polymers at the surface of the nanoparticles was verified by NOESY NMR and most importantly by electron microscopy analysis in two and three dimensions. The Janus structure is additionally shown to affect the aggregation behavior of the nanoparticles.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 6.319
Times cited: 44
DOI: 10.1039/C5CC10454H
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“High viscosity to highly dispersed PtPd bimetallic nanocrystals for enhanced catalytic activity and stability”. Ying J, Hu Z-Y, Yang X-Y, Wei H, Xiao Y-X, Janiak C, Mu S-C, Tian G, Pan M, Van Tendeloo G, Su B-L, Chemical communications 52, 8219 (2016). http://doi.org/10.1039/c6cc00912c
Abstract: A facile high-viscosity-solvent method is presented to synthesize PtPd bimetallic nanocrystals highly dispersed in different mesostructures (2D and 3D structures), porosities (large and small pore sizes), and compositions (silica and carbon). Further, highly catalytic activity, stability and durability of the nanometals have been proven in different catalytic reactions.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 6.319
Times cited: 19
DOI: 10.1039/c6cc00912c
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“Polydopamine nanocoated whole-cell asymmetric biocatalysts”. Wang L, Hu Z-Y, Yang X-Y, Zhang B-B, Geng W, Van Tendeloo G, Su B-L, Chemical communications 53, 6617 (2017). http://doi.org/10.1039/C7CC01283G
Abstract: Our whole-cell biocatalyst with a polydopamine nanocoating shows high catalytic activity (5 times better productivity than the native cell) and reusability (84% of the initial yield after 5 batches, 8 times higher than the native cell) in asymmetric reduction. It also integrates with titania, silica, and magnetic nanoparticles for multi-functionalization.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 6.319
Times cited: 15
DOI: 10.1039/C7CC01283G
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“Disentangling the effect of seed size and crystal habit on gold nanoparticle seeded growth”. González-Rubio G, de Oliveira TM, Altantzis T, La Porta A, Guerrero-Martínez A, Bals S, Scarabelli L, Liz-Marzán LM, Chemical communications 53, 11360 (2017). http://doi.org/10.1039/C7CC06854A
Abstract: Oxidative etching was used to produce gold seeds of different sizes and crystal habits. Following detailed characterization, the seeds were grown under different conditions. Our results bring new insights toward understanding the effect of size and crystallinity on the growth of anisotropic particles, whilst identifying guidelines for the optimisation of new synthetic protocols of predesigned seeds.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 6.319
Times cited: 29
DOI: 10.1039/C7CC06854A
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“The design of magneto-plasmonic nanostructures formed by magnetic Prussian Blue-type nanocrystals decorated with Au nanoparticles”. Sanchis-Gual R, Susic I, Torres-Cavanillas R, Arenas-Esteban D, Bals S, Mallah T, Coronado-Puchau M, Coronado E, Chemical Communications 57, 1903 (2021). http://doi.org/10.1039/D0CC08034A
Abstract: We have developed a general protocol for the preparation of hybrid nanostructures formed by nanoparticles (NPs) of molecule-based magnets based on Prussian Blue Analogues (PBAs) decorated with plasmonic Au NPs of different shapes. By adjusting the pH, Au NPs can be attached preferentially along the edges of the PBA or randomly on the surface. The protocol allows tuning the plasmonic properties of the hybrids in the whole visible spectrum.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 6.319
Times cited: 5
DOI: 10.1039/D0CC08034A
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“Optical encoding of luminescent carbon nanodots in confined spaces”. Bartholomeeusen E, De Cremer G, Kennes K, Hammond C, Hermans I, Lu J-B, Schryvers D, Jacobs PA, Roeffaers MBJ, Hofkens J, Sels BF, Coutino-Gonzalez E, Chemical Communications 57, 11952 (2021). http://doi.org/10.1039/D1CC04777A
Abstract: Stable emissive carbon nanodots were generated in zeolite crystals using near infrared photon irradiation gradually converting the occluded organic template, originally used to synthesize the zeolite crystals, into discrete luminescent species consisting of nano-sized carbogenic fluorophores, as ascertained using Raman microscopy, and steady-state and time-resolved spectroscopic techniques. Photoactivation in a confocal laser fluorescence microscope allows 3D resolved writing of luminescent carbon nanodot patterns inside zeolites providing a cost-effective and non-toxic alternative to previously reported metal-based nanoclusters confined in zeolites, and opens up opportunities in bio-labelling and sensing applications.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 6.319
DOI: 10.1039/D1CC04777A
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“Occupancy of lattice positions probed by X-ray photoelectron diffraction : a case study of tetradymite topological insulators”. Vladimirova NV, Frolov AS, Sanchez-Barriga J, Clark OJ, Matsui F, Usachov DY, Muntwiler M, Callaert C, Hadermann J, Neudachina VS, Tamm ME, Yashina LV, Surfaces and interfaces 36, 102516 (2023). http://doi.org/10.1016/J.SURFIN.2022.102516
Abstract: Occupancy of different structural positions in a crystal lattice often seems to play a key role in material prop-erties. Several experimental techniques have been developed to uncover this issue, all of them being mostly bulk sensitive. However, many materials including topological insulators (TIs), which are among the most intriguing modern materials, are intended to be used in devices as thin films, for which the sublattice occupancy may differ from the bulk. One of the possible approaches to occupancy analysis is X-ray Photoelectron Diffraction (XPD), a structural method in surface science with chemical sensitivity. We applied this method in a case study of Sb2(Te1-xSex)3 mixed crystals, which belong to prototypical TIs. We used high-angle annular dark field (HAADF) scanning transmission electron microscopy (STEM) as a reference method to verify our analysis. We revealed that the XPD data for vacuum cleaved bulk crystals are in excellent agreement with the reference ones. Also, we demonstrate that the anion occupancy near a naturally formed surface can be rather different from that of the bulk. The present results are relevant for a wide range of compositions where the system remains a topological phase, as we ultimately show by probing the transiently occupied topological surface state above the Fermi level by ultrafast photoemission.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 6.2
DOI: 10.1016/J.SURFIN.2022.102516
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“Spinel nanoparticles on stick-like Freudenbergite nanocomposites as effective smart-removal photocatalysts for the degradation of organic pollutants under visible light”. Ciocarlan R-G, Seftel EM, Gavrila R, Suchea M, Batuk M, Mertens M, Hadermann J, Cool P, Journal Of Alloys And Compounds 820, 153403 (2020). http://doi.org/10.1016/j.jallcom.2019.153403
Abstract: A series of mixed nanocomposite materials was synthetized, containing a Ferrite phase type Zn1-xNixFe2O4 and a Freudenbergite phase type Na2Fe2Ti6O16, where x = 0; 0.2; 0.4; 0.6; 0.8; 1. The choice for this combination is based on the good adsorption properties of Freudenbergite for dye molecules, and the small bandgap energy of Ferrite spinel, allowing activation of the catalysts under visible light irradiation. A two steps synthesis protocol was used to obtain the smart-removal nanocomposites. Firstly, the spinel structure was obtained via the co-precipitation route followed by the addition of the Ti-source and formation of the Freudenbergite system. The role of cations on the formation mechanism and an interesting interchange of cations between spinel and Freudenbergite structures was clarified by a TEM study. Part of the Ti4+ penetrated the spinel structure and, at the same time, part of the Fe3+ formed the Freudenbergite system. The photocatalytic activity was studied under visible light, reaching for the best catalysts a 67% and 40% mineralization degree for methylene blue and rhodamine 6G respectively, after 6 h of irradiation. In the same conditions, the well-known commercial P25 (Degussa) managed to mineralize only 12% and 3% of methylene blue and rhodamine 6G, respectively. Due to the remarkable magnetic properties of Ferrites, a convenient recovery and reuse of the catalysts is possible after the photocatalytic tests. Based on the excellent catalytic performance of the nanocomposites under visible light and their ease of separation out of the solution after the catalytic reaction, the newly developed composite catalysts are considered very effective for wastewater treatment.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA)
Impact Factor: 6.2
DOI: 10.1016/j.jallcom.2019.153403
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“Atomic-resolution fine structure and chemical reaction mechanism of Gd/YbAl₃, thermoelectric-magnetocaloric heterointerface”. Chen C, Sang X, Cui W, Xing L, Nie X, Zhu W, Wei P, Hu Z-Y, Zhang Q, Van Tendeloo G, Zhao W, Journal Of Alloys And Compounds 831, 154722 (2020). http://doi.org/10.1016/J.JALLCOM.2020.154722
Abstract: Thermoelectric materials and magnetocaloric materials are promising candidates for solid-state refrigeration applications. The combination of thermoelectric and magnetocaloric effects could potentially lead to more efficient refrigeration techniques. We designed and successfully synthesized Gd/YbAl3 composites using a YbAl3 matrix with good low-temperature thermoelectric performance and Gd microspheres with a high magnetocaloric performance, using a sintering condition of 750 degrees C and 50 MPa. Using aberration-corrected scanning transmission electron microscopy (STEM), it was discovered that the heterointerface between Gd and YbAl 3 is composed of five sequential interfacial layers: GdAl3, GdAl2, GdAl, Gd3Al2, and Gd3Al. The diffusion of Al atoms plays a crucial role in the formation of these interfacial layers, while Yb or Gd do not participate in the interlayer diffusion. This work provides the essential structural information for further optimizing and designing high-performance composites for thermoelectric-magnetocaloric hybrid refrigeration applications. (C) 2020 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 6.2
Times cited: 1
DOI: 10.1016/J.JALLCOM.2020.154722
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“Photocatalytic process optimisation for ethylene oxidation”. Tytgat T, Hauchecorne B, Abakumov AM, Smits M, Verbruggen SW, Lenaerts S, Chemical engineering journal 209, 494 (2012). http://doi.org/10.1016/j.cej.2012.08.032
Abstract: When studying photocatalysis it is important to consider, beside the chemical approach, the engineering part related to process optimisation. To achieve this a fixed bed photocatalytic set-up consisting of different catalyst placings, in order to vary catalyst distribution, is studied. The use of a fixed quantity of catalyst placed packed or randomly distributed in the reactor, results in an almost double degradation for the distributed catalyst. Applying this knowledge leads to an improved performance with limited use of catalyst. A reactor only half filled with catalyst leads to higher degradation performance compared to a completely filled reactor. Taking into account this simple process optimisation by better distributing the catalyst a more sustainable photocatalytic air purification process is achieved. (C) 2012 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 6.216
Times cited: 12
DOI: 10.1016/j.cej.2012.08.032
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“Smart heating profiles for the synthesis of benzene bridged periodic mesoporous organosilicas”. Smeulders G, van Oers C, Van Havenbergh K, Houthoofd K, Mertens M, Martens JA, Bals S, Maes BUW, Meynen V, Cool P, Chemical engineering journal 175, 585 (2011). http://doi.org/10.1016/j.cej.2011.09.116
Abstract: In this study the effects of the heating rate and heating time on the formation of crystal-like benzene bridged periodic mesoporous organosilicas (PMOs) are investigated. The time needed to heat up an autoclave during the hydrothermal treatment has shown to be crucial in the synthesis of PMOs, while the total duration of heating gave rise to only minor differences. By choosing a smart heating profile, superior PMO materials can be obtained in a short time. Different heating profiles in a range from one minute to one hour are adopted by microwave equipment and compared with conventional heating methods. The heating rate has a large influence on the porosity characteristics and the uniformity of the obtained particles. Moreover, two new alternative synthetic strategies to adopt the smart heating profile are presented, in order to give some possible solutions for the expensive microwave equipment.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA); Organic synthesis (ORSY)
Impact Factor: 6.216
Times cited: 7
DOI: 10.1016/j.cej.2011.09.116
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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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“Simultaneous creation of metal nanoparticles in metal organic frameworks via spray drying technique”. Gholampour N, Chaemchuen S, Hu Z-Y, Mousavi B, Van Tendeloo G, Verpoort F, Chemical engineering journal 322, 702 (2017). http://doi.org/10.1016/J.CEJ.2017.04.085
Abstract: In-situ fabrication of palladium(0) nanoparticles inside zeolitic imidazolate frameworks (ZIF-8) has been established via one-step facile spray-dry technique. Crystal structures and morphologies of the Pd@ZIF-8 samples are investigated by powder XRD, TEM, SAED, STEM, and EDX techniques. High angle annular dark field scanning transmission electron microscopy (HAAD-STEM) and 3D tomographic analysis confirm the presence of palladium nanoparticles inside the ZIF-8 structure. The porosity, surface area and N-2 physisorption properties are evaluated for Pd@ZIF-8 with various palladium contents. Furthermore, Pd@ZIF-8 samples are effectively applied as heterogeneous catalysts in alkenes hydrogenation. This straightforward method is able to speed up the synthesis of encapsulation of metal nanoparticles in metal organic frameworks. (C) 2017 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 6.216
Times cited: 14
DOI: 10.1016/J.CEJ.2017.04.085
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“Tuning the turnover frequency and selectivity of photocatalytic CO2 reduction to CO and methane using platinum and palladium nanoparticles on Ti-Beta zeolites”. Blommaerts N, Hoeven N, Arenas Esteban D, Campos R, Mertens M, Borah R, Glisenti A, De Wael K, Bals S, Lenaerts S, Verbruggen SW, Cool P, Chemical Engineering Journal 410, 128234 (2021). http://doi.org/10.1016/j.cej.2020.128234
Abstract: A Ti-Beta zeolite was used in gas phase photocatalytic CO2 reduction to reduce the charge recombination rate and increase the surface area compared to P25 as commercial benchmark, reaching 607 m2 g-1. By adding Pt nanoparticles, the selectivity can be tuned toward CO, reaching a value of 92% and a turnover frequency (TOF) of 96 µmol.gcat-1.h-1, nearly an order of magnitude higher in comparison with P25. By adding Pd nanoparticles the selectivity can be shifted from CO (70% for a bare Ti-Beta zeolite), toward CH4 as the prevalent species (60%). In this way, the selectivity toward CO or CH4 can be tuned by either using Pt or Pd. The TOF values obtained in this work outperform reported state-of-the-art values in similar research. The improved activity by adding the nanoparticles was attributed to an improved charge separation efficiency, together with a plasmonic contribution of the metal nanoparticles under the applied experimental conditions.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL); Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA); AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 6.216
Times cited: 15
DOI: 10.1016/j.cej.2020.128234
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“Resistive switching in Ag₂Te semiconductor modulated by Ag+-ion diffusion and phase transition”. Guo A, Bai H, Liang Q, Feng L, Su X, Van Tendeloo G, Wu J, Advanced Electronic Materials , 2200850 (2022). http://doi.org/10.1002/AELM.202200850
Abstract: Memristors are considered to be the fourth circuit element and have great potential in areas like logic operations, information storage, and neuromorphic computing. The functional material in a memristor, which has a nonlinear resistance, is the key component to be developed. Herein, resistive switching is demonstrated and the structural evolutions in Ag2Te are examined under an external electric field. It is shown that the electroresistance effect is originating from an electronically triggered phase transition together with directional Ag+-ion diffusion. Using in situ transmission electron microscopy, the phase transition from the monoclinic alpha-Ag2Te into the face-centered cubic beta-Ag2Te, accompanied by a change in resistance, is directly observed. Diffusion of Ag+-ions modulates the localized density of Ag+-ion vacancies, leading to a change in electrical conductivity and influences the threshold voltage to trigger the phase transition. During the electric field-driven phase transition, the spontaneous and localized multiple polarizations from the low-symmetry alpha-Ag2Te (referring to an antiferroelectric structure) are vanishing in the cubic beta-Ag2Te (referring to a paraelectric structure). The abrupt resistance change of thin Ag2Te caused by the phase transition and modulated by the applied electric field demonstrates its great potential as functional material in volatile memory and memristors with a low-energy consumption.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 6.2
DOI: 10.1002/AELM.202200850
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“Phase coexistence induced surface roughness in V2O3/Ni magnetic heterostructures”. Ignatova K, Vlasov E, Seddon SD, Gauquelin N, Verbeeck J, Wermeille D, Bals S, Hase TPA, Arnalds UB, APL Materials 12 (2024). http://doi.org/10.1063/5.0195961
Abstract: We present an investigation of the microstructure changes in V2O3 as it goes through its inherent structural phase transition. Using V2O3 films with a well-defined crystal structure deposited by reactive magnetron sputtering on r-plane Al2O3 substrates, we study the phase coexistence region and its impact on the surface roughness of the films and the magnetic properties of overlying Ni magnetic layers in V2O3/Ni hybrid magnetic heterostructures. The simultaneous presence of two phases in V2O3 during its structural phase transition was identified with high resolution x-ray diffraction and led to an increase in surface roughness observed using x-ray reflectivity. The roughness reaches its maximum at the midpoint of the transition. In V2O3/Ni hybrid heterostructures, we find a concomitant increase in the coercivity of the magnetic layer correlated with the increased roughness of the V2O3 surface. The chemical homogeneity of the V2O3 is confirmed through transmission electron microscopy analysis. High-angle annular dark field imaging and electron energy loss spectroscopy reveal an atomically flat interface between Al2O3 and V2O3, as well as a sharp interface between V2O3 and Ni.
Keywords: A1 Journal Article; Electron Microscopy for Materials Science (EMAT) ;
Impact Factor: 6.1
DOI: 10.1063/5.0195961
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“Refinement of the uranium dispersion corrections from anomalous diffraction”. Leinders G, Grendal OG, Arts I, Bes R, Prozheev I, Orlat S, Fitch A, Kvashnina K, Verwerft M, Journal of Applied Crystallography 57, 284 (2024). http://doi.org/10.1107/S1600576723010889
Abstract: The evolution of the uranium chemical state in uranium compounds, principally in the oxides, is of concern in the context of nuclear fuel degradation under storage and repository conditions, and in accident scenarios. The U–O system shows complicated phase relations between single-valence uranium dioxide (UO<sub>2</sub>) and different mixed-valence compounds (<italic>e.g.</italic>U<sub>4</sub>O<sub>9</sub>, U<sub>3</sub>O<sub>7</sub>and U<sub>3</sub>O<sub>8</sub>). To try resolving the electronic structure associated with unique atomic positions, a combined application of diffraction and spectroscopic techniques, such as diffraction anomalous fine structure (DAFS), can be considered. Reported here is the application of two newly developed routines for assessing a DAFS data set, with the aim of refining the uranium X-ray dispersion corrections. High-resolution anomalous diffraction data were acquired from polycrystalline powder samples of UO<sub>2</sub>(containing tetravalent uranium) and potassium uranate (KUO<sub>3</sub>, containing pentavalent uranium) using synchrotron radiation in the vicinity of the U<italic>L</italic><sub>3</sub>edge (17.17 keV). Both routines are based on an iterative refinement of the dispersion corrections, but they differ in either using the intensity of a selection of reflections or doing a full-pattern (Rietveld method) refinement. The uranium dispersion corrections obtained using either method are in excellent agreement with each other, and they show in great detail the chemical shifts and differences in fine structure expected for tetravalent and pentavalent uranium. This approach may open new possibilities for the assessment of other, more complicated, materials such as mixed-valence compounds. Additionally, the DAFS methodology can offer a significant resource optimization because each data set contains both structural (diffraction) and chemical (spectroscopy) information, which can avoid the requirement to use multiple experimental stations at synchrotron sources.
Keywords: A1 Journal Article; Electron Microscopy for Materials Science (EMAT) ;
Impact Factor: 6.1
DOI: 10.1107/S1600576723010889
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