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“Three-dimensional elemental mapping at the atomic scale in bimetallic nanocrystals”. Goris B, de Backer A, Van Aert S, Gómez-Graña S, Liz-Marzán LM, Van Tendeloo G, Bals S, Nano letters 13, 4236 (2013). http://doi.org/10.1021/nl401945b
Abstract: A thorough understanding of the three-dimensional (3D) atomic structure and composition of coreshell nanostructures is indispensable to obtain a deeper insight on their physical behavior. Such 3D information can be reconstructed from two-dimensional (2D) projection images using electron tomography. Recently, different electron tomography techniques have enabled the 3D characterization of a variety of nanostructures down to the atomic level. However, these methods have all focused on the investigation of nanomaterials containing only one type of chemical element. Here, we combine statistical parameter estimation theory with compressive sensing based tomography to determine the positions and atom type of each atom in heteronanostructures. The approach is applied here to investigate the interface in coreshell Au@Ag nanorods but it is of great interest in the investigation of a broad range of nanostructures.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 12.712
Times cited: 90
DOI: 10.1021/nl401945b
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“Exploring different inelastic projection mechanisms for electron tomography”. Goris B, Bals S, van den Broek W, Verbeeck J, Van Tendeloo G, Ultramicroscopy 111, 1262 (2011). http://doi.org/10.1016/j.ultramic.2011.02.007
Abstract: Several different projection mechanisms that all make use of inelastically scattered electrons are used for electron tomography. The advantages and the disadvantages of these methods are compared to HAADFSTEM tomography, which is considered as the standard electron tomography technique in materials science. The different inelastic setups used are energy filtered transmission electron microscopy (EFTEM), thickness mapping based on the log-ratio method and bulk plasmon mapping. We present a comparison that can be used to select the best inelastic signal for tomography, depending on different parameters such as the beam stability and nature of the sample. The appropriate signal will obviously also depend on the exact information which is requested.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Impact Factor: 2.843
Times cited: 21
DOI: 10.1016/j.ultramic.2011.02.007
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“Atomic-scale determination of surface facets in gold nanorods”. Goris B, Bals S, van den Broek W, Carbó-Argibay E, Gómez-Graña S, Liz-Marzán LM, Van Tendeloo G, Nature materials 11, 930 (2012). http://doi.org/10.1038/NMAT3462
Abstract: It is widely accepted that the physical properties of nanostructures depend on the type of surface facets1, 2. For Au nanorods, the surface facets have a major influence on crucial effects such as reactivity and ligand adsorption and there has been controversy regarding facet indexing3, 4. Aberration-corrected electron microscopy is the ideal technique to study the atomic structure of nanomaterials5, 6. However, these images correspond to two-dimensional (2D) projections of 3D nano-objects, leading to an incomplete characterization. Recently, much progress was achieved in the field of atomic-resolution electron tomography, but it is still far from being a routinely used technique. Here we propose a methodology to measure the 3D atomic structure of free-standing nanoparticles, which we apply to characterize the surface facets of Au nanorods. This methodology is applicable to a broad range of nanocrystals, leading to unique insights concerning the connection between the structure and properties of nanostructures.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 39.737
Times cited: 261
DOI: 10.1038/NMAT3462
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“Comparative Hall studies in the electron- and hole-doped manganites La0.33Ca0.67MnO3 and La0.70Ca0.30MnO3”. Gordon I, Wagner P, Das A, Vanacken J, Moshchalkov VV, Bruynseraede Y, Schuddinck W, Van Tendeloo G, Ziese M, Borghs G, Physical review : B : condensed matter and materials physics 62, 11633 (2000). http://doi.org/10.1103/PhysRevB.62.11633
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.836
Times cited: 18
DOI: 10.1103/PhysRevB.62.11633
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“Nitrogen fixation with water vapor by nonequilibrium plasma : toward sustainable ammonia production”. Gorbanev Y, Vervloessem E, Nikiforov A, Bogaerts A, Acs Sustainable Chemistry &, Engineering 8, 2996 (2020). http://doi.org/10.1021/ACSSUSCHEMENG.9B07849
Abstract: Ammonia is a crucial nutrient used for plant growth and as a building block in the pharmaceutical and chemical industry, produced via nitrogen fixation of the ubiquitous atmospheric N2. Current industrial ammonia production relies heavily on fossil resources, but a lot of work is put into developing nonfossil-based pathways. Among these is the use of nonequilibrium plasma. In this work, we investigated water vapor as a H source for nitrogen fixation into NH3 by nonequilibrium plasma. The highest selectivity toward NH3 was observed with low amounts of added H2O vapor, but the highest production rate was reached at high H2O vapor contents. We also studied the role of H2O vapor and of the plasma-exposed liquid H2O in nitrogen fixation by using isotopically labeled water to distinguish between these two sources of H2O. We show that added H2O vapor, and not liquid H2O, is the main source of H for NH3 generation. The studied catalyst- and H2-free method offers excellent selectivity toward NH3 (up to 96%), with energy consumption (ca. 95–118 MJ/mol) in the range of many plasma-catalytic H2-utilizing processes.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 8.4
Times cited: 14
DOI: 10.1021/ACSSUSCHEMENG.9B07849
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“Combining experimental and modelling approaches to study the sources of reactive species induced in water by the COST RF plasma jet”. Gorbanev Y, Verlackt CCW, Tinck S, Tuenter E, Foubert K, Cos P, Bogaerts A, Physical chemistry, chemical physics 20, 2797 (2018). http://doi.org/10.1039/C7CP07616A
Abstract: The vast biomedical potential of cold atmospheric pressure plasmas (CAPs) is governed by the formation of reactive species. These biologically active species are formed upon the interaction of CAPs with the surroundings. In biological milieu, water plays an essential role. The development of biomedical CAPs thus requires understanding of the sources of the reactive species in aqueous media exposed to the plasma. This is especially important in case of the COST RF plasma jet, which is developed as a reference microplasma system. In this work, we investigated the formation of the OH radicals, H atoms and H2O2 in aqueous solutions exposed to the COST plasma jet. This was done by combining experimental and modelling approaches. The liquid phase species were analysed using UV-Vis spectroscopy and spin trapping with hydrogen isotopes and electron paramagnetic resonance (EPR) spectroscopy. The discrimination between the species formed from the liquid phase and the gas phase molecules was performed by EPR and 1H-NMR analyses of the liquid samples. The concentrations of the reactive species in the gas phase plasma were obtained using a zero-dimensional (0D) chemical kinetics computational model. A three-dimensional (3D) fluid dynamics model was developed to provide information on the induced humidity in the plasma effluent. The comparison of the experimentally obtained trends for the formation of the species as a function of the feed gas and effluent humidity with the modelling results suggest that all reactive species detected in our system are mostly formed in the gas phase plasma inside the COST jet, with minor amounts arising from the plasma effluent humidity.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.123
Times cited: 23
DOI: 10.1039/C7CP07616A
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“Reaction of chloride anion with atomic oxygen in aqueous solutions: can cold plasma help in chemistry research?”.Gorbanev Y, Van der Paal J, Van Boxem W, Dewilde S, Bogaerts A, Physical chemistry, chemical physics 21, 4117 (2019). http://doi.org/10.1039/C8CP07550F
Abstract: Cold atmospheric plasma in contact with solutions has many applications, but its chemistry contains many unknowns such as the undescribed reactions with solutes. By combining experiments and modelling, we report the first direct demonstration of the reaction of chloride with oxygen atoms in aqueous solutions exposed to cold plasma.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.123
Times cited: 4
DOI: 10.1039/C8CP07550F
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“Analysis of Short-Lived Reactive Species in Plasma–Air–Water Systems: The Dos and the Do Nots”. Gorbanev Y, Privat-Maldonado A, Bogaerts A, Analytical Chemistry 90, 13151 (2018). http://doi.org/10.1021/acs.analchem.8b03336
Abstract: This Feature addresses the analysis of the reactive species generated by nonthermal atmospheric
pressure plasmas, which are widely employed in industrial and biomedical research, as well as first
clinical applications. We summarize the progress in detection of plasma-generated short-lived
reactive oxygen and nitrogen species in aqueous solutions, discuss the potential and limitations of
various analytical methods in plasma−liquid systems, and provide an outlook on the possible future
research goals in development of short-lived reactive species analysis methods for a general
nonspecialist audience.
Keywords: A1 Journal Article; Plasma, laser ablation and surface modeling Antwerp (PLASMANT) ;
Impact Factor: 6.32
Times cited: 17
DOI: 10.1021/acs.analchem.8b03336
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“Applications of the COST Plasma Jet: More than a Reference Standard”. Gorbanev Y, Golda J, Gathen VS, Bogaerts A, Plasma 2, 316 (2019). http://doi.org/10.3390/plasma2030023
Abstract: The rapid advances in the field of cold plasma research led to the development of many plasma jets for various purposes. The COST plasma jet was created to set a comparison standard between different groups in Europe and the world. Its physical and chemical properties are well studied, and diagnostics procedures are developed and benchmarked using this jet. In recent years, it has been used for various research purposes. Here, we present a brief overview of the reported applications of the COST plasma jet. Additionally, we discuss the chemistry of the plasma-liquid systems with this plasma jet, and the properties that make it an indispensable system for plasma research.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
DOI: 10.3390/plasma2030023
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“Plasma catalysis in ammonia production and decomposition: Use it, or lose it?”.Gorbanev Y, Fedirchyk I, Bogaerts A, Current Opinion in Green and Sustainable Chemistry 47, 100916 (2024). http://doi.org/10.1016/j.cogsc.2024.100916
Abstract: The combination of plasma with catalysis for the synthesis and decomposition of NH3 is an attractive route to the production of carbon-neutral fertiliser and energy carriers and its conversion into H2. Recent years have seen fast developments in the field of plasma-catalytic NH3 life cycle. This work summarises the most recent advances in plasma-catalytic and related NH3-focussed processes, identifies some of the most important discoveries, and addresses plausible strategies for future developments in plasma-based NH3 technology.
Keywords: A1 Journal Article; Plasma Nitrogen fixation Ammonia Plasma catalysis Production and decomposition; Plasma, laser ablation and surface modeling Antwerp (PLASMANT) ;
Impact Factor: 9.3
DOI: 10.1016/j.cogsc.2024.100916
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“Al2O3-Supported Transition Metals for Plasma-Catalytic NH3 Synthesis in a DBD Plasma: Metal Activity and Insights into Mechanisms”. Gorbanev Y, Engelmann Y, van’t Veer K, Vlasov E, Ndayirinde C, Yi Y, Bals S, Bogaerts A, Catalysts 11, 1230 (2021). http://doi.org/10.3390/catal11101230
Abstract: N2 fixation into NH3 is one of the main processes in the chemical industry. Plasma catalysis is among the environmentally friendly alternatives to the industrial energy-intensive Haber-Bosch process. However, many questions remain open, such as the applicability of the conventional catalytic knowledge to plasma. In this work, we studied the performance of Al2O3-supported Fe, Ru, Co and Cu catalysts in plasma-catalytic NH3 synthesis in a DBD reactor. We investigated the effects of different active metals, and different ratios of the feed gas components, on the concentration and production rate of NH3, and the energy consumption of the plasma system. The results show that the trend of the metal activity (common for thermal catalysis) does not appear in the case of plasma catalysis: here, all metals exhibited similar performance. These findings are in good agreement with our recently published microkinetic model. This highlights the virtual independence of NH3 production on the metal catalyst material, thus validating the model and indicating the potential contribution of radical adsorption and Eley-Rideal reactions to the plasma-catalytic mechanism of NH3 synthesis.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT); Movement Antwerp (MOVANT)
Impact Factor: 3.082
Times cited: 19
DOI: 10.3390/catal11101230
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“A microanalytical study of the gills of aluminium-exposed rainbow trout (Salmo gairdneri)”. Goossenaerts C, Van Grieken R, Jacob W, Witters H, Vanderborght O, International journal of environmental analytical chemistry 34, 227 (1988). http://doi.org/10.1080/03067319808026840
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1080/03067319808026840
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“Holstein polarons near surfaces”. Goodvin GL, Covaci L, Berciu M, Physical Review Letters 103, 176402 (2009). http://doi.org/10.1103/PhysRevLett.103.176402
Abstract: We study the effects of a nearby surface on the spectral weight of a Holstein polaron, using the inhomogeneous momentum average approximation which is accurate over the entire range of electron-phonon (e-ph) coupling strengths. The broken translational symmetry is taken into account exactly. We find that the e-ph coupling gives rise to a large additional surface potential, with strong retardation effects, which may bind surface states even when they are not normally expected. The surface, therefore, has a significant effect and bulk properties are recovered only very far away from it. These results demonstrate that interpretation in terms of bulk quantities of spectroscopic data sensitive only to a few surface layers is not always appropriate.
Keywords: A1 Journal article
Impact Factor: 8.462
Times cited: 8
DOI: 10.1103/PhysRevLett.103.176402
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“Controlled Alloying of Au@Ag Core–Shell Nanorods Induced by Femtosecond Laser Irradiation”. González‐Rubio G, Díaz‐Núñez P, Albrecht W, Manzaneda‐González V, Bañares L, Rivera A, Liz‐Marzán LM, Peña‐Rodríguez O, Bals S, Guerrero‐Martínez A, Advanced Optical Materials , 2002134 (2021). http://doi.org/10.1002/adom.202002134
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 6.875
Times cited: 10
DOI: 10.1002/adom.202002134
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“Micelle-directed chiral seeded growth on anisotropic gold nanocrystals”. González-Rubio G, Mosquera J, Kumar V, Pedrazo-Tardajos A, Llombart P, Solís DM, Lobato I, Noya EG, Guerrero-Martínez A, Taboada JM, Obelleiro F, MacDowell LG, Bals S, Liz-Marzán LM, Science 368, 1472 (2020). http://doi.org/10.1126/science.aba0980
Abstract: Surfactant-assisted seeded growth of metal nanoparticles (NPs) can be engineered to produce anisotropic gold nanocrystals with high chiroptical activity through the templating effect of chiral micelles formed in the presence of dissymmetric cosurfactants. Mixed micelles adsorb on gold nanorods, forming quasihelical patterns that direct seeded growth into NPs with pronounced morphological and optical handedness. Sharp chiral wrinkles lead to chiral plasmon modes with high dissymmetry factors (~0.20). Through variation of the dimensions of chiral wrinkles, the chiroptical properties can be tuned within the visible and near-infrared electromagnetic spectrum. The micelle-directed mechanism allows extension to other systems, such as the seeded growth of chiral platinum shells on gold nanorods. This approach provides a reproducible, simple, and scalable method toward the fabrication of NPs with high chiral optical activity.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 56.9
Times cited: 187
DOI: 10.1126/science.aba0980
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“Formation of Hollow Gold Nanocrystals by Nanosecond Laser Irradiation”. González-Rubio G, Milagres de Oliveira T, Albrecht W, Díaz-Núñez P, Castro-Palacio JC, Prada A, González RI, Scarabelli L, Bañares L, Rivera A, Liz-Marzán LM, Peña-Rodríguez O, Bals S, Guerrero-Martínez A, Journal Of Physical Chemistry Letters 11, 670 (2020). http://doi.org/10.1021/acs.jpclett.9b03574
Abstract: The irradiation of spherical gold nanoparticles (AuNPs) with nanosecond laser pulses induces shape transformations yielding nanocrystals with an inner cavity. The concentration of the stabilizing surfactant, the use of moderate pulse fluences, and the size of the irradiated AuNPs determine the efficiency of the process and the nature of the void. Hollow nanocrystals are obtained when molecules from the surrounding medium (e.g., water and organic matter derived from the surfactant) are trapped during laser pulse irradiation. These experimental observations suggest the existence of a subtle balance between the heating and cooling processes experienced by the nanocrystals, which induce their expansion and subsequent recrystallization keeping exogenous matter inside. The described approach provides valuable insight into the mechanism of interaction of pulsed nanosecond laser with AuNPs, along with interesting prospects for the development of hollow plasmonic nanoparticles with potential applications related to gas and liquid storage at the nanoscale.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 5.7
Times cited: 15
DOI: 10.1021/acs.jpclett.9b03574
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“Disconnecting Symmetry Breaking from Seeded Growth for the Reproducible Synthesis of High Quality Gold Nanorods”. Gonzalez-Rubio G, Kumar V, Llombart P, Diaz-Nunez P, Bladt E, Altantzis T, Bals S, Pena-Rodriguez O, Noya EG, MacDowell LG, Guerrero-Martinez A, Liz-Marzan LM, ACS nano 13, 4424 (2019). http://doi.org/10.1021/ACSNANO.8B09658
Abstract: One of the major difficulties hindering the widespread application of colloidal anisotropic plasmonic nanoparticles is the limited robustness and reproducibility of multistep synthetic methods. We demonstrate herein that the reproducibility and reliability of colloidal gold nanorod (AuNR) synthesis can be greatly improved by disconnecting the symmetry-breaking event from the seeded growth process. We have used a modified silver-assisted seeded growth method in the presence of the surfactant hexadecyltrimethylammonium bromide and n-decanol as a co-surfactant to prepare small AuNRs in high yield, which were then used as seeds for the growth of high quality AuNR colloids. Whereas the use of n-decanol provides a more-rigid micellar system, the growth on anisotropic seeds avoids sources of irreproducibility during the symmetry breaking step, yielding uniform AuNR colloids with narrow plasmon bands, ranging from 600 to 1270 nm, and allowing the fine-tuning of the final dimensions. This method provides a robust route for the preparation of high quality AuNR colloids with tunable morphology, size, and optical response in a reproducible and scalable manner.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Applied Electrochemistry & Catalysis (ELCAT)
Impact Factor: 13.942
Times cited: 100
DOI: 10.1021/ACSNANO.8B09658
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“Femtosecond Laser-Controlled Tip-to-Tip Assembly and Welding of Gold Nanorods”. Gonzalez-Rubio G, Gonzalez-Izquierdo J, Banares L, Tardajos G, Rivera A, Altantzis T, Bals S, Pena-Rodriguez O, Guerrero-Martinez A, Liz-Marzan LM, Nano letters 15, 8282 (2015). http://doi.org/10.1021/acs.nanolett.5b03844
Abstract: Directed assembly of gold nanorods through the use of dithiolated molecular linkers is one of the most efficient methodologies for the morphologically controlled tip-to-tip assembly of this type of anisotropic nanocrystals. However, in a direct analogy to molecular polymerization synthesis, this process is characterized by difficulties in chain-growth control over nanoparticle oligomers. In particular, it is nearly impossible to favor the formation of one type of oligomer, making the methodology hard to use for actual applications in nanoplasmonics. We propose here a light-controlled synthetic procedure that allows obtaining selected plasmonic oligomers in high yield and with reaction times in the scale of minutes by irradiation with low fluence near-infrared (NIR) femtosecond laser pulses. Selective inhibition of the formation of gold nanorod n-mers (trimers) with a longitudinal localized surface plasmon in resonance with a 800 nm Ti:sapphire laser, allowed efficient trapping of the (n – 1)-mers (dimers) by hot spot mediated photothermal decomposition of the interparticle molecular linkers. Laser irradiation at higher energies produced near-field enhancement at the interparticle gaps, which is large enough to melt gold nanorod tips, offering a new pathway toward tip-to-tip welding of gold nanorod oligomers with a plasmonic response at the NIR. Thorough optical and electron microscopy characterization indicates that plasmonic oligomers can be selectively trapped and welded, which has been analyzed in terms of a model that predicts with reasonable accuracy the relative concentrations of the main plasmonic species.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 12.712
Times cited: 101
DOI: 10.1021/acs.nanolett.5b03844
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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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“Intensifying mass and heat transfer using a high-g stator-rotor vortex chamber”. Gonzalez-Quiroga A, Shtern V, Perreault P, Vandewalle L, Marin GB, Van Geem KM, Chemical Engineering And Processing 169, 108638 (2021). http://doi.org/10.1016/J.CEP.2021.108638
Abstract: Vortex reactors take advantage of the synergy between enhanced heat and mass transfer rates and multifunctional phenomena at different temporal and spatial scales. Proof-of-concept experiments with our novel and innovative STAtor-Rotor VOrtex Chamber (STARVOC) confirm its advantageous features for the sustainable production of chemicals and fuels. STARVOC is a high-g contactor that uses carrier flow (gas or liquid) tangential injection to drive a rotor attached to low-friction bearings. The vortex chamber inside the rotor contains a secondary phase or phases, such as a solids bed, a liquid layer, or a suspension. Carrier fluid passes through the perforated rotor wall and contacts a densely and uniformly distributed secondary phase with enhanced slip velocities. Experiments focused on pressure profiles, rotor angular velocity, and solids azimuthal velocity. With air as the carrier fluid and different solid particle beds as the secondary phase, STARVOC reached bed azimuthal velocities up to four-fold compared to those reached in Gas-Solid Vortex Units with fully static geometry. These results show its potential to improve interfacial heat and mass transfer rates and take advantage of flow energy and angular momentum. Due to its process intensification capabilities, STARVOC is a promising alternative for the state-of-the-art chemical industry.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 2.234
DOI: 10.1016/J.CEP.2021.108638
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“Azimuthal and radial flow patterns of 1g-Geldart B-type particles in a gas-solid vortex reactor”. Gonzalez-Quiroga A, Kulkarni SR, Vandewalle L, Perreault P, Goel C, Heynderickx GJ, van Geem KM, Marin GB, Powder technology 354, 410 (2019). http://doi.org/10.1016/J.POWTEC.2019.06.015
Abstract: Processes requiring intensive interfacial momentum, mass and heat exchange between gases and particulate solids can be greatly enhanced by operating in a centrifugal field. This is realized in the Gas-Solid Vortex Reactor (GSVR) with centrifugal accelerations up to two orders of magnitude higher than the Earth's gravitational acceleration. Here, the flow patterns of two 1g-Geldart B-type particles are experimentally assessed, over the gas inlet velocity range 82–126 m s−1, in an 80 mm diameter and 15 mm height GSVR. The particles are monosized aluminum spheres of 0.5 mm diameter, and walnut shell in the sieve fraction 0.50–0.56 mm and aspect ratio 1.3 ± 0.2. Two dimensional Particle Image Velocimetry combined with Digital Image Analysis and pressure measurements revealed that periodic fluctuations in solids azimuthal and radial velocity between gas inlet slots are strongly related to the average solids azimuthal velocity and bed uniformity. Aluminum particles feature steeper changes in azimuthal velocity and more attenuated changes in radial velocity than walnut shell particles. Within the assessed gas inlet velocity range the solids bed of aluminum exhibits average azimuthal velocities and bed voidages 40–50% and ≈10% lower than those of walnut shell. The aerodynamic response time of the particles, i.e. ρsdp2/18μg, emerged as an important parameter to assess the influence of the carrier gas jet on the radial deflection of the particles and the interaction solids bed-outer wall. Too low aerodynamic response time relates to nonuniformity in bed voidage due to solids radial velocity fluctuations. Excessive aerodynamic response time indicates low solids azimuthal velocities due to solids bed-outer wall friction.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1016/J.POWTEC.2019.06.015
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“Emergence of coupled rotor dynamics in metal-organic frameworks via tuned steric interactions”. Gonzalez-Nelson A, Mula S, Simenas M, Balciunas S, Altenhof AR, Vojvodin CS, Canossa S, Banys J, Schurko RW, Coudert F-X, van der Veen MA, Journal Of The American Chemical Society 143, 12053 (2021). http://doi.org/10.1021/JACS.1C03630
Abstract: The organic components in metal-organic frameworks (MOFs) are unique: they are embedded in a crystalline lattice, yet, as they are separated from each other by tunable free space, a large variety of dynamic behavior can emerge. These rotational dynamics of the organic linkers are especially important due to their influence over properties such as gas adsorption and kinetics of guest release. To fully exploit linker rotation, such as in the form of molecular machines, it is necessary to engineer correlated linker dynamics to achieve their cooperative functional motion. Here, we show that for MIL-53, a topology with closely spaced rotors, the phenylene functionalization allows researchers to tune the rotors' steric environment, shifting linker rotation from completely static to rapid motions at frequencies above 100 MHz. For steric interactions that start to inhibit independent rotor motion, we identify for the first time the emergence of coupled rotation modes in linker dynamics. These findings pave the way for function-specific engineering of gear-like cooperative motion in MOFs.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 13.858
DOI: 10.1021/JACS.1C03630
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“Structural, mechanical and electronic properties of two-dimensional structure of III-arsenide (111) binary compounds: An ab-initio study”. Gonzalez-Garcia A, Lopez-Perez W, Rivera-Julio J, Peeters FM, Mendoza-Estrada V, Gonzalez-Hernandez R, Computational materials science 144, 285 (2018). http://doi.org/10.1016/J.COMMATSCI.2017.12.050
Abstract: Structural, mechanical and electronic properties of two-dimensional single-layer hexagonal structures in the (111) crystal plane of IIIAs-ZnS systems (III = B, Ga and In) are studied by first-principles calculations based on density functional theory (DFT). Elastic and phonon dispersion relation display that 2D h-IIIAs systems (III = B, Ga and In) are both mechanical and dynamically stable. Electronic structures analysis show that the semiconducting nature of the 3D-IIIAs compounds is retained by their 2D single layer counterpart. Furthermore, density of states reveals the influence of sigma and pi bonding in the most stable geometry (planar or buckled) for 2D h-IIIAs systems. Calculations of elastic constants show that the Young's modulus, bulk modulus and shear modulus decrease for 2D h-IIIAs binary compounds as we move down on the group of elements of the periodic table. In addition, as the bond length between the neighboring cation-anion atoms increases, the 2D h-IIIAs binary compounds display less stiffness and more plasticity. Our findings can be used to understand the contribution of the r and p bonding in the most stable geometry (planar or buckled) for 2D h-IIIAs systems. Structural and electronic properties of h-IIIAs systems as a function of the number of layers have been also studied. It is shown that h-BAs keeps its planar geometry while both h-GAs and h-InAs retained their buckled ones obtained by their single layers. Bilayer h-IIIAs present the same bandgap nature of their counterpart in 3D. As the number of layers increase from 2 to 4, the bandgap width for layered h-IIIAs decreases until they become semimetal or metal. Interestingly, these results are different to those found for layered h-GaN. The results presented in this study for single and few-layer h-IIIAs structures could give some physical insights for further theoretical and experimental studies of 2D h-IIIV-like systems. (C) 2017 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.292
Times cited: 3
DOI: 10.1016/J.COMMATSCI.2017.12.050
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“Tunable 2D-gallium arsenide and graphene bandgaps in a graphene/GaAs heterostructure : an ab initio study”. Gonzalez-Garcia A, Lopez-Perez W, Gonzalez-Hernandez R, Rodriguez JA, Milošević, MV, Peeters FM, Journal of physics : condensed matter 31, 265502 (2019). http://doi.org/10.1088/1361-648X/AB0D70
Abstract: The bandgap behavior of 2D-GaAs and graphene have been investigated with van der Waals heterostructured into a yet unexplored graphene/GaAs bilayer, under both uniaxial stress along c axis and different planar strain distributions. The 2D-GaAs bandgap nature changes from Gamma-K indirect in isolated monolayer to Gamma-Gamma direct in graphene/GaAs bilayer. In the latter, graphene exhibits a bandgap of 5 meV. The uniaxial stress strongly affects the graphene electronic bandgap, while symmetric in-plane strain does not open the bandgap in graphene. Nevertheless, it induces remarkable changes on the GaAs bandgap-width around the Fermi level. However, when applying asymmetric in-plane strain to graphene/GaAs, the graphene sublattice symmetry is broken, and the graphene bandgap is open at the Fermi level to a maximum width of 814 meV. This value is much higher than that reported for just graphene under asymmetric strain. The Gamma-Gamma direct bandgap of GaAs remains unchanged in graphene/ GaAs under different types of applied strain. The analyses of phonon dispersion and the elastic constants yield the dynamical and mechanical stability of the graphene/GaAs system, respectively. The calculated mechanical properties for bilayer heterostructure are better than those of their constituent monolayers. This finding, together with the tunable graphene bandgap not only by the strength but also by the direction of the strain, enhance the potential for strain engineering of ultrathin group-III-V electronic devices hybridized by graphene.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.649
Times cited: 10
DOI: 10.1088/1361-648X/AB0D70
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“Two-dimensional hydrogenated buckled gallium arsenide: an ab initio study”. Gonzalez-Garcia A, Lopez-Perez W, Gonzalez-Hernandez R, Rivera-Julio J, Espejo C, Milošević, MV, Peeters FM, Journal Of Physics-Condensed Matter 32, 145502 (2020). http://doi.org/10.1088/1361-648X/AB6043
Abstract: First-principles calculations have been carried out to investigate the stability, structural and electronic properties of two-dimensional (2D) hydrogenated GaAs with three possible geometries: chair, zigzag-line and boat configurations. The effect of van der Waals interactions on 2D H-GaAs systems has also been studied. These configurations were found to be energetic and dynamic stable, as well as having a semiconducting character. Although 2D GaAs adsorbed with H tends to form a zigzag-line configuration, the energy differences between chair, zigzag-line and boat are very small which implies the metastability of the system. Chair and boat configurations display a – direct bandgap nature, while pristine 2D-GaAs and zigzag-line are indirect semiconductors. The bandgap sizes of all configurations are also hydrogen dependent, and wider than that of pristine 2D-GaAs with both PBE and HSE functionals. Even though DFT-vdW interactions increase the adsorption energies and reduce the equilibrium distances of H-GaAs systems, it presents, qualitatively, the same physical results on the stability and electronic properties of our studied systems with PBE functional. According to our results, 2D buckled gallium arsenide is a good candidate to be synthesized by hydrogen surface passivation as its group III-V partners 2D buckled gallium nitride and boron nitride. The hydrogenation of 2D-GaAs tunes the bandgap of pristine 2D-GaAs, which makes it a potential candidate for optoelectronic applications in the blue and violet ranges of the visible electromagnetic spectrum.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.7
Times cited: 2
DOI: 10.1088/1361-648X/AB6043
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“Transition-metal adatoms on 2D-GaAs: a route to chiral magnetic 2D materials by design”. González-García A, López-Pérez W, González-Hernández R, Bacaksiz C, Šabani D, Milošević, MV, Peeters FM, Journal Of Physics-Condensed Matter 33, 145803 (2021). http://doi.org/10.1088/1361-648X/abe077
Abstract: Using relativistic density-functional calculations, we examine the magneto-crystalline anisotropy and exchange properties of transition-metal atoms adsorbed on 2D-GaAs. We show that single Mn and Mo atom (Co and Os) strongly bind on 2D-GaAs, and induce local out-of-plane (in-plane) magnetic anisotropy. When a pair of TM atoms is adsorbed on 2D-GaAs in a close range from each other, magnetisation properties change (become tunable) with respect to concentrations and ordering of the adatoms. In all cases, we reveal presence of strong Dzyaloshinskii–Moriya interaction. These results indicate novel pathways towards two-dimensional chiral magnetic materials by design, tailored for desired applications in magneto-electronics.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.649
Times cited: 1
DOI: 10.1088/1361-648X/abe077
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“Lead(II) formate in Rembrandt's Night Watch : detection and distribution from the macro- to the micro-scale”. Gonzalez V, Fazlic I, Cotte M, Vanmeert F, Gestels A, De Meyer S, Broers F, Hermans J, van Loon A, Janssens K, Noble P, Keune K, Angewandte Chemie: international edition in English , 1 (2023). http://doi.org/10.1002/ANIE.202216478
Abstract: The Night Watch, painted in 1642 and on view in the Rijksmuseum in Amsterdam, is considered Rembrandt's most famous work. X-ray powder diffraction (XRPD) mapping at multiple length scales revealed the unusual presence of lead(II) formate, Pb(HCOO)(2), in several areas of the painting. Until now, this compound was never reported in historical oil paints. In order to get insights into this phenomenon, one possible chemical pathway was explored thanks to the preparation and micro-analysis of model oil paint media prepared by heating linseed oil and lead(II) oxide (PbO) drier as described in 17(th) century recipes. Synchrotron radiation based micro-XRPD (SR-mu-XRPD) and infrared microscopy were combined to identify and map at the micro-scale various neo-formed lead-based compounds in these model samples. Both lead(II) formate and lead(II) formate hydroxide Pb(HCOO)(OH) were detected and mapped, providing new clues regarding the reactivity of lead driers in oil matrices in historical paintings.
Keywords: A1 Journal article; Art; Antwerp X-ray Imaging and Spectroscopy (AXIS)
Impact Factor: 16.6
DOI: 10.1002/ANIE.202216478
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“X-ray diffraction mapping for cultural heritage science : a review of experimental configurations and applications”. Gonzalez V, Cotte M, Vanmeert F, de Nolf W, Janssens K, Chemistry: a European journal 26, 1703 (2019). http://doi.org/10.1002/CHEM.201903284
Abstract: X-ray diffraction (XRD) mapping consists in the acquisition of XRD patterns at each pixel (or voxel) of an area (or volume). The spatial resolution ranges from the micrometer (mu XRD) to the millimeter (MA-XRD) scale, making the technique relevant for tiny samples up to large objects. Although XRD is primarily used for the identification of different materials in (complex) mixtures, additional information regarding the crystallite size, their orientation, and their in-depth distribution can also be obtained. Through mapping, these different types of information can be located on the studied sample/object. Cultural heritage objects are usually highly heterogeneous, and contain both original and later (degradation, conservation) materials. Their structural characterization is required both to determine ancient manufacturing processes and to evaluate their conservation state. Together with other mapping techniques, XRD mapping is increasingly used for these purposes. Here, the authors review applications as well as the various configurations for XRD mapping (synchrotron/laboratory X-ray source, poly-/monochromatic beam, micro/macro beam, 2D/3D, transmission/reflection mode). On-going hardware and software developments will further establish the technique as a key tool in heritage science.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 5.317
DOI: 10.1002/CHEM.201903284
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“Padé, approximants for the groundstate energy of closed-shell quantum dots”. Gonzalez A, Partoens B, Peeters FM, Physical review : B : condensed matter and materials physics 56, 15740 (1997). http://doi.org/10.1103/PhysRevB.56.15740
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 18
DOI: 10.1103/PhysRevB.56.15740
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“Ground-state energy of confined bosons in two dimensions”. Gonzalez A, Partoens B, Matulis A, Peeters FM, Physical review : B : condensed matter and materials physics 59, 1653 (1999). http://doi.org/10.1103/PhysRevB.59.1653
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 13
DOI: 10.1103/PhysRevB.59.1653
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