“Modelling of synchrotron SAXS patterns of silicalite-1 zeolite during crystallization”. Aerts A, Follens LRA, Biermans E, Bals S, Van Tendeloo G, Loppinet B, Kirschhock CEA, Martens JA, Physical chemistry, chemical physics 13, 4318 (2011). http://doi.org/10.1039/c0cp01592j
Abstract: Synchrotron small angle X-ray scattering (SAXS) was used to characterize silicalite-1 zeolite crystallization from TEOS/TPAOH/water clear sol. SAXS patterns were recorded over a broad range of length scales, enabling the simultaneous monitoring of nanoparticles and crystals occurring at various stages of the synthesis. A simple two-population model accurately described the patterns. Nanoparticles were modeled by polydisperse coreshell spheres and crystals by monodisperse oblate ellipsoids. These models were consistent with TEM images. The SAXS results, in conjunction with in situ light scattering, showed that nucleation of crystals occurred in a short period of time. Crystals were uniform in size and shape and became increasingly anisotropic during growth. In the presence of nanoparticles, crystal growth was fast. During crystal growth, the number of nanoparticles decreased gradually but their size was constant. These observations suggested that the nanoparticles were growth units in an aggregative crystal growth mechanism. Crystals grown in the presence of nanoparticles developed a faceted habit and intergrowths. In the final stages of growth, nanoparticles were depleted. Concurrently, the crystal growth rate decreased significantly.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.123
Times cited: 22
DOI: 10.1039/c0cp01592j
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“Modelling molecular adsorption on charged or polarized surfaces: a critical flaw in common approaches”. Bal KM, Neyts EC, Physical chemistry, chemical physics 20, 8456 (2018). http://doi.org/10.1039/C7CP08209F
Abstract: A number of recent computational material design studies based on density functional theory (DFT) calculations have put forward a new class of materials with electrically switchable chemical characteristics that can be exploited in the development of tunable gas storage and electrocatalytic applications. We find systematic flaws in almost every computational study of gas adsorption on polarized or charged surfaces, stemming from an improper and unreproducible treatment of periodicity, leading to very large errors of up to 3 eV in some cases. Two simple corrective procedures that lead to consistent results are proposed, constituting a crucial course correction to the research in the field.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.123
Times cited: 8
DOI: 10.1039/C7CP08209F
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“Modeling the physicochemical properties of natural deep eutectic solvents : a review”. Kovács A, Billen P, Cornet I, Wijnants M, Neyts EC, Chemsuschem 13, 3789 (2020). http://doi.org/10.1002/CSSC.202000286
Abstract: Natural deep eutectic solvents (NADES) are mixtures of naturally derived compounds with a significantly decreased melting point due to the specific interactions among the constituents. NADES have benign properties (low volatility, flammability, toxicity, cost) and tailorable physicochemical properties (by altering the type and molar ratio of constituents), hence they are often considered as a green alternative to common organic solvents. Modeling the relation between their composition and properties is crucial though, both for understanding and predicting their behavior. Several efforts were done to this end, yet this review aims at structuring the present knowledge as an outline for future research. First, we reviewed the key properties of NADES and relate them to their structure based on the available experimental data. Second, we reviewed available modeling methods applicable to NADES. At the molecular level, density functional theory and molecular dynamics allow interpreting density differences and vibrational spectra, and computation of interaction energies. Additionally, properties at the level of the bulk media can be explained and predicted by semi-empirical methods based on ab initio methods (COSMO-RS) and equation of state models (PC-SAFT). Finally, methods based on large datasets are discussed; models based on group contribution methods and machine learning. A combination of bulk media and dataset modeling allows qualitative prediction and interpretation of phase equilibria properties on the one hand, and quantitative prediction of melting point, density, viscosity, surface tension and refractive indices on the other hand. In our view, multiscale modeling, combining the molecular and macroscale methods, will strongly enhance the predictability of NADES properties and their interaction with solutes, yielding truly tailorable solvents to accommodate (bio)chemical reactions.
Keywords: A1 Journal article; Engineering sciences. Technology; Intelligence in PRocesses, Advanced Catalysts and Solvents (iPRACS); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT); Biochemical Wastewater Valorization & Engineering (BioWaVE)
Impact Factor: 8.4
DOI: 10.1002/CSSC.202000286
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“Modeling plasmas in analytical chemistry—an example of cross-fertilization”. Bogaerts A, Analytical And Bioanalytical Chemistry 412, 6059 (2020). http://doi.org/10.1007/s00216-020-02587-8
Abstract: This paper gives an overview of the modeling work developed in our group in the last 25 years for various plasmas used in analytical spectrochemistry, i.e., glow discharges (GDs), inductively coupled plasmas (ICPs), and laser ablation (LA) for sample introduction in the ICP and for laser-induced breakdown spectroscopy (LIBS). The modeling approaches are briefly presented, which are different for each case, and some characteristic results are illustrated. These plasmas are used not only in analytical chemistry but also in other applications, and the insights obtained in these other fields were quite helpful for us to develop models for the analytical plasmas. Likewise, there is now a huge interest in plasma–liquid interaction, atmospheric pressure glow discharges (APGDs), and dielectric barrier discharges (DBDs) for environmental, medical, and materials applications of plasmas. The insights obtained in these fields are also very relevant for ambient desorption/ionization sources and for liquid sampling, which are nowadays very popular in analytical chemistry, and they could be very helpful in developing models for these sources as well.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.3
DOI: 10.1007/s00216-020-02587-8
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“Modeling Plasma-based CO2and CH4Conversion in Mixtures with N2, O2, and H2O: The Bigger Plasma Chemistry Picture”. Wang W, Snoeckx R, Zhang X, Cha MS, Bogaerts A, The journal of physical chemistry: C : nanomaterials and interfaces 122, 8704 (2018). http://doi.org/10.1021/acs.jpcc.7b10619
Abstract: Because of the unique properties of plasma technology, its use in gas conversion applications is gaining significant interest around the globe. Plasma-based CO2 and CH4 conversion has become a major research area. Many investigations have already been performed regarding the single-component gases, that is, CO2 splitting and CH4 reforming, as well as for two-component mixtures, that is, dry reforming of methane
(CO2/CH4), partial oxidation of methane (CH4/O2), artificial photosynthesis (CO2/H2O), CO2 hydrogenation (CO2/H2), and even first steps toward the influence of N2 impurities have been taken, that is, CO2/N2 and CH4/N2. In this Feature Article we briefly discuss the advances made in literature for these different steps from a plasma chemistry modeling point of view. Subsequently, we present a comprehensive plasma chemistry set, combining the knowledge gathered in this field so far and supported with extensive experimental data. This set can be used for chemical kinetics plasma modeling for all possible combinations of CO2, CH4, N2, O2, and H2O to investigate the bigger picture of the underlying plasmachemical pathways for these mixtures in a dielectric barrier discharge plasma. This is extremely valuable
for the optimization of existing plasma-based CO2 conversion and CH4 reforming processes as well as for investigating the influence of N2, O2, and H2O on these processes and even to support plasma-based multireforming processes.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.536
Times cited: 28
DOI: 10.1021/acs.jpcc.7b10619
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“Modeling of the sputtering process of cubic silver halide microcrystals and its relevance in depth profiling by secondary ion-mass spectrometry (SIMS)”. Lenaerts J, Verlinden G, Ignatova VA, van Vaeck L, Gijbels R, Geuens I, Fresenius' journal of analytical chemistry 370, 654 (2001). http://doi.org/10.1007/s002160100880
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Times cited: 3
DOI: 10.1007/s002160100880
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“Modeling of the plasma chemistry and plasmasurface interactions in reactive plasmas”. Bogaerts A, De Bie C, Eckert M, Georgieva V, Martens T, Neyts E, Tinck S, Pure and applied chemistry 82, 1283 (2010). http://doi.org/10.1351/PAC-CON-09-09-20
Abstract: In this paper, an overview is given of modeling activities going on in our research group, for describing the plasma chemistry and plasmasurface interactions in reactive plasmas. The plasma chemistry is calculated by a fluid approach or by hybrid Monte Carlo (MC)fluid modeling. An example of both is illustrated in the first part of the paper. The example of fluid modeling is given for a dielectric barrier discharge (DBD) in CH4/O2, to describe the partial oxidation of CH4 into value-added chemicals. The example of hybrid MCfluid modeling concerns an inductively coupled plasma (ICP) etch reactor in Ar/Cl2/O2, including also the description of the etch process. The second part of the paper deals with the treatment of plasmasurface interactions on the atomic level, with molecular dynamics (MD) simulations or a combination of MD and MC simulations.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.626
Times cited: 13
DOI: 10.1351/PAC-CON-09-09-20
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“Modeling of CO2Splitting in a Microwave Plasma: How to Improve the Conversion and Energy Efficiency”. Berthelot A, Bogaerts A, The journal of physical chemistry: C : nanomaterials and interfaces 121, 8236 (2017). http://doi.org/10.1021/acs.jpcc.6b12840
Abstract: Microwave plasmas are one of the most promising techniques for CO2 conversion into value-added chemicals and fuels since they are very energy efficient. Nevertheless, experiments show that this high energy efficiency is only reached at low pressures and significantly drops toward atmospheric pressure, which is a clear limitation for industrial applications. In this paper, we use a zerodimensional reaction kinetics model to simulate a CO2 microwave plasma in a pressure range from 50 mbar to 1 bar, in order to evaluate the reasons for this decrease in energy efficiency at atmospheric pressure. The code includes a detailed description of the vibrational kinetics of CO2, CO, and O2 as well as the energy exchanges between them because the vibrational kinetics is known to be crucial for energy efficient CO2 splitting. First, we use a self-consistent gas temperature calculation in order to assess the key performance indicators for CO2 splitting, i.e., the CO2 conversion and corresponding energy efficiency. Our results indicate that lower pressures and higher power densities lead to more vibrational excitation, which is beneficial for the conversion. We also demonstrate the key role of the gas temperature. The model predicts the highest conversion and energy efficiencies at pressures around 300 mbar, which is in agreement with experiments from the literature. We also show the beneficial aspect of fast gas cooling in the afterglow at high pressure. In a second step, we study in more detail the effects of pressure, gas temperature, and power density on the vibrational distribution function and on the dissociation and recombination mechanisms of CO2, which define the CO2 splitting efficiency. This study allows us to identify the limiting factors of CO2 conversion and to propose potential solutions to improve the process.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.536
Times cited: 47
DOI: 10.1021/acs.jpcc.6b12840
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“Modeling and experimental study of trichloroethylene abatement with a negative direct current corona discharge”. Vandenbroucke AM, Aerts R, Van Gaens W, De Geyter N, Leys C, Morent R, Bogaerts A, Plasma chemistry and plasma processing 35, 217 (2015). http://doi.org/10.1007/s11090-014-9584-7
Abstract: In this work, we study the abatement of dilute trichloroethylene (TCE) in air with a negative direct current corona discharge. A numerical model is used to theoretically investigate the underlying plasma chemistry for the removal of TCE, and a reaction pathway for the abatement of TCE is proposed. The Cl atom, mainly produced by dissociation of COCl, is one of the controlling species in the TCE destruction chemistry and contributes to the production of chlorine containing by-products. The effect of humidity on the removal efficiency is studied and a good agreement is found between experiments and the model for both dry (5 % relative humidity (RH)) and humid air (50 % RH). An increase of the relative humidity from 5 % to 50 % has a negative effect on the removal efficiency, decreasing by ±15 % in humid air. The main loss reactions for TCE are with ClO·, O· and CHCl2. Finally, the by-products and energy cost of TCE abatement are discussed.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.355
Times cited: 9
DOI: 10.1007/s11090-014-9584-7
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“Mo2C as a high capacity anode material: a first-principles study”. Çakir D, Sevik C, Gulseren O, Peeters FM, Journal of materials chemistry A : materials for energy and sustainability 4, 6029 (2016). http://doi.org/10.1039/C6TA01918H
Abstract: The adsorption and diffusion of Li, Na, K and Ca atoms on a Mo2C monolayer are systematically investigated by using first principles methods. We found that the considered metal atoms are strongly bound to the Mo2C monolayer. However, the adsorption energies of these alkali and earth alkali elements decrease as the coverage increases due to the enhanced repulsion between the metal ions. We predict a significant charge transfer from the ad-atoms to the Mo2C monolayer, which indicates clearly the cationic state of the metal atoms. The metallic character of both pristine and doped Mo2C ensures a good electronic conduction that is essential for an optimal anode material. Low migration energy barriers are predicted as small as 43 meV for Li, 19 meV for Na and 15 meV for K, which result in the very fast diffusion of these atoms on Mo2C. For Mo2C, we found a storage capacity larger than 400 mA h g(-1) by the inclusion of multilayer adsorption. Mo2C expands slightly upon deposition of Li and Na even at high concentrations, which ensures the good cyclic stability of the atomic layer. The calculated average voltage of 0.68 V for Li and 0.30 V for Na ions makes Mo2C attractive for low charging voltage applications.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Impact Factor: 8.867
Times cited: 202
DOI: 10.1039/C6TA01918H
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“MnFe0.5Ru0.5O3 : an above-room-temperature antiferromagnetic semiconductor”. Tan X, McCabe EE, Orlandi F, Manuel P, Batuk M, Hadermann J, Deng Z, Jin C, Nowik I, Herber R, Segre CU, Liu S, Croft M, Kang C-J, Lapidus S, Frank CE, Padmanabhan H, Gopalan V, Wu M, Li M-R, Kotliar G, Walker D, Greenblatt M, Journal of materials chemistry C : materials for optical and electronic devices 7, 509 (2019). http://doi.org/10.1039/C8TC05059G
Abstract: A transition-metal-only MnFe0.5Ru0.5O3 polycrystalline oxide was prepared by a reaction of starting materials MnO, MnO2, Fe2O3, RuO2 at 6 GPa and 1873 K for 30 minutes. A combination of X-ray and neutron powder diffraction refinements indicated that MnFe0.5Ru0.5O3 adopts the corundum (alpha-Fe2O3) structure type with space group R (3) over barc, in which all metal ions are disordered. The centrosymmetric nature of the MnFe0.5Ru0.5O3 structure is corroborated by transmission electron microscopy, lack of optical second harmonic generation, X-ray absorption near edge spectroscopy, and Mossbauer spectroscopy. X-ray absorption near edge spectroscopy of MnFe0.5Ru0.5O3 showed the oxidation states of Mn, Fe, and Ru to be 2+/3+, 3+, and similar to 4+, respectively. Resistivity measurements revealed that MnFe0.5Ru0.5O3 is a semiconductor. Magnetic measurements and magnetic structure refinements indicated that MnFe0.5Ru0.5O3 orders antiferromagnetically around 400 K, with magnetic moments slightly canted away from the c axis. Fe-57 Mossbauer confirmed the magnetic ordering and Fe3+ (S = 5/2) magnetic hyperfine splitting. First principles calculations are provided to understand the electronic structure more thoroughly. A comparison of synthesis and properties of MnFe0.5Ru0.5O3 and related corundum Mn2BB'O-6 derivatives is discussed.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 5.256
Times cited: 1
DOI: 10.1039/C8TC05059G
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“Mn(I) in an extended oxide : the synthesis and characterization of La1-xCaxMnO2+\delta (0.6\leq x\leq1)”. Dixon E, Hadermann J, Ramos S, Goodwin AL, Hayward MA, Journal of the American Chemical Society 133, 18397 (2011). http://doi.org/10.1021/ja207616c
Abstract: Reduction of La1xCaxMnO3 (0.6 ≤ x ≤ 1) perovskite phases with sodium hydride yields materials of composition La1xCaxMnO2+δ. The calcium-rich phases (x = 0.9, 1) adopt (La0.9Ca0.1)0.5Mn0.5O disordered rocksalt structures. However local structure analysis using reverse Monte Carlo refinement of models against pair distribution functions obtained from neutron total scattering data reveals lanthanum-rich La1xCaxMnO2+δ (x = 0.6, 0.67, 0.7) phases adopt disordered structures consisting of an intergrowth of sheets of MnO6 octahedra and sheets of MnO4 tetrahedra. X-ray absorption data confirm the presence of Mn(I) centers in La1xCaxMnO2+δ phases with x < 1. Low-temperature neutron diffraction data reveal La1xCaxMnO2+δ (x = 0.6, 0.67, 0.7) phases become antiferromagnetically ordered at low temperature.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 13.858
Times cited: 33
DOI: 10.1021/ja207616c
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“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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“Mixed tellurides Ni3-xGaTe2 (0\leq x\leq0.65): crystal and electronic structures, properties, and nickel deficiency effects on vacancy ordering”. Isaeva AA, Makarevich ON, Kutznetsov AN, Doert T, Abakumov AM, Van Tendeloo G, European journal of inorganic chemistry , 1395 (2010). http://doi.org/10.1002/ejic.200901027
Abstract: The Ni3-xGaTe2 series of compounds (0 x 0.65) was synthesized by a high-temperature ceramic technique at 750 °C. Crystal structures of three compounds in the series were determined by X-ray powder diffraction: Ni2.98(1)GaTe2 (RI = 0.042, Rp = 0.023, Rwp = 0.035), Ni2.79(1)GaTe2 (RI = 0.053, Rp = 0.028, Rwp = 0.039), Ni2.58(1)GaTe2 (RI = 0.081, Rp = 0.037, Rwp = 0.056); the structures were verified by electron diffraction and, for the former compound, high-resolution electron microscopy. The compounds crystallize in a hexagonal lattice with P63/mmc, and the structures can be regarded as a hexagonal close-packed array with a -Ga-Te-Te- stacking sequence. The octahedral and trigonal bipyramidal voids in the hcp structure are selectively filled with Ni atoms to form one entirely occupied and two partially occupied sites, thus allowing variations in the nickel content in the series of compounds Ni3-xGaTe2 (0 x 0.65). A superstructure with asup = 2asub (P63/mmc) has been identified for Ni3-xGaTe2 (0.5 x 0.65) by electron diffraction. Real-space, high-resolution images confirm an ordering of Ni atoms and vacancies inthe ab plane. Quantum-chemical calculations performed forNi3-xGaTe2 (x = 0, 0.25, 0.75, 1) suggest anisotropic metallic conductivity and Pauli paramagnetic behavior that are experimentally confirmed for Ni3GaTe2.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.444
Times cited: 8
DOI: 10.1002/ejic.200901027
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“Mixed hemi/ad-micelle sodium dodecyl sulfate-coated magnetic iron oxide nanoparticles for the efficient removal and trace determination of rhodamine-B and rhodamine-6G”. Ranjbari E, Hadjmohammadi MR, Kiekens F, De Wael K, Analytical chemistry 87, 7894 (2015). http://doi.org/10.1021/ACS.ANALCHEM.5B01676
Abstract: Mixed hemi/ad-micelle sodium dodecyl sulfate (SDS)-coated magnetic iron oxide nanoparticles (MHAMS-MIONPs) were used as an efficient adsorbent for both removal and preconcentration of two important carcinogenic xanthine dyes named rhodamine-B (RB) and rhodamine-6G (RG). To gain insight in the configuration of SDS molecules on the surface of MIONPs, zeta potential measurements were performed in different [SDS]/[MIONP] ratios. Zeta potential data indicated that mixed hemi/ad-micelle MHAM was formed in [SDS]/[MIONP] ratios over the range of 1.1 to 7.3. Parameters affecting the adsorption of dyes were optimized as removal efficiency by one variable at-a-time and response surface methodology; the obtained removal efficiencies were ∼100%. Adsorption kinetic and equilibrium studies, under the optimum condition (pH = 2; amount of MIONPs = 87.15 mg; [SDS]/[MIONP] ratio = 2.9), showed that adsorption of both dyes are based on the pseudo-second-order and the Langmuir isotherm models, respectively. The maximum adsorption capacities for RB and RG were 385 and 323 mg g1, respectively. MHAMS-MIONPs were also applied for extraction of RB and RG. Under optimum conditions (pH = 2; amount of damped MHAMS-MIONPs = 90 mg; eluent solvent volume = 2.6 mL of 3% acetic acid in acetonitrile), extraction recoveries for 0.5 mg L1 of RB and RG were 98% and 99%, with preconcentration factors of 327 and 330, respectively. Limit of detection obtained for rhodamine dyes were <0.7 ng mL1. Finally, MHAMS-MIONPs were successfully applied for both removal and trace determination of RB and RG in environmental and wastewater samples.
Keywords: A1 Journal article; Pharmacology. Therapy; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 6.32
Times cited: 36
DOI: 10.1021/ACS.ANALCHEM.5B01676
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“Mitigation strategies for radiation damage in the analysis of ancient materials”. Bertrand L, Schoeeder S, Anglos D, Breese MBH, Janssens K, Moini M, Simon A, Trends in analytical chemistry 66, 128 (2015). http://doi.org/10.1016/J.TRAC.2014.10.005
Abstract: The study of materials in cultural heritage artifacts and micro-samples benefits from diagnostic techniques based on intense radiation sources, such as synchrotrons, ion-beam accelerators and lasers. While most of the corresponding techniques are classified as non-destructive, investigation with photons or charged particles entails a number of fundamental processes that may induce changes in materials. These changes depend on irradiation parameters, properties of materials and environmental factors. In some cases, radiation-induced damage may be detected by visual inspection. When it is not, irradiation may still lead to atomic and molecular changes resulting in immediate or delayed alteration and bias of future analyses. Here we review the effects of radiation reported on a variety of cultural heritage materials and describe the usual practice for assessing short-term and long-term effects. This review aims to raise awareness and encourage subsequent research activities to limit radiation side effects.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 8.442
Times cited: 35
DOI: 10.1016/J.TRAC.2014.10.005
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“Microwave-assisted bromination of double-walled carbon nanotubes”. Colomer J-F, Marega R, Traboulsi H, Meneghetti M, Van Tendeloo G, Bonifazi D, Chemistry of materials 21, 4747 (2009). http://doi.org/10.1021/cm902029m
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 9.466
Times cited: 46
DOI: 10.1021/cm902029m
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“Microstructural aspects of the degradation behavior of SnO2-based anodes for aluminum electrolysis”. Vassiliev SY, Laurinavichute VK, Abakumov AM, Govorov VA, Bendovskii EB, Turner S, Filatov AY, Tarasovskii VP, Borzenko AG, Alekseeva AM, Antipov EV, Journal of the electrochemical society 157, C178 (2010). http://doi.org/10.1149/1.3327903
Abstract: The performance of SnO2 ceramic anodes doped with copper and antimony oxides was examined in cryolite alumina melts under anodic polarization at different cryolite ratios, temperatures, times, and current densities. The corroded part consists of a narrow strong corrosion zone at the anode surface with damage of the intergrain contacts and a large increase in porosity, a wider moderate corrosion zone with a smaller porosity increase, and a Cu depletion zone, where the ceramic retains its initial microstructure and a slight porosity increase occurs due to the removal of the Cu-rich inclusions. Mechanical destruction of the anode was never observed in the 10100 h tests. A microstructural model of the ceramic was suggested, consisting of grains with an Sb-doped SnO2 grain core surrounded by an ~200 to 500 nm grain shell where SnO2 was simultaneously doped with Sb and Mn+ (M=Cu2+,Fe3+,Al3+). The grains were separated by a few nanometers thick Cu-enriched grain boundaries. Different secondary charge carrier (holes) concentrations and electric conductivities in the grain core and grain shell result in a higher current density at the intergrain regions that leads to their profound degradation, especially in the low temperature acidic melt.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.259
Times cited: 3
DOI: 10.1149/1.3327903
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“Microprobe speciation analysis of inorganic solids by Fourier transform laser mass spectrometry”. Poels K, van Vaeck L, Gijbels R, Analytical chemistry 70, 504 (1998). http://doi.org/10.1021/ac9709108
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 6.32
Times cited: 32
DOI: 10.1021/ac9709108
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“Mg8Rh4B: a new type of boron stabilized Ti2Ni structure”. Alekseeva AM, Abakumov AM, Leithe-Jasper A, Schnelle W, Prots Y, Van Tendeloo G, Antipov EV, Grin Y, Journal of solid state chemistry 179, 2751 (2006). http://doi.org/10.1016/j.jssc.2005.11.029
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.299
Times cited: 11
DOI: 10.1016/j.jssc.2005.11.029
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“Mg1-xRhB, a new boridometallide with 2D polyanion”. Alekseeva AM, Abakumov AM, Leithe-Jasper A, Schnelle W, Prots Y, Hadermann J, Van Tendeloo G, Antipov EV, Grin Y, Zeitschrift für anorganische und allgemeine Chemie 631, 1047 (2005). http://doi.org/10.1002/zaac.200400479
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.144
Times cited: 13
DOI: 10.1002/zaac.200400479
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“Metals@MOFs –, loading MOFs with metal nanoparticles for hybrid functions”. Meilikhov M, Yusenko K, Esken D, Turner S, Van Tendeloo G, Fischer RA, European journal of inorganic chemistry 2010, 3701 (2010). http://doi.org/10.1002/ejic.201000473
Abstract: Metalorganic frameworks (MOFs) as well as porous coordination polymers (PCPs) are porous, organicinorganic hybrid solids with zeolite-like structures and properties. Due to their extraordinarily high surface area and well defined pore structure MOFs can be used for the stabilization of metal nanoparticles with adjustable size. The embedded metal nanoparticles are still accessible for other reagents due to the high porosity of the MOF systems. This fact makes metal@MOF systems especially interesting for heterogeneous catalysis, gas storage and chemical sensing. This review compiles the cases of metal nanoparticles supported by or embedded into MOFs reported so far and the main aspects and problems associated with these novel nanocomposite systems. The determination of the dispersion and the location of the particles at the MOF support, the control of the loading degree and its effect on the catalytic activity of the system are discussed as well as the partial degradation of the MOF structure upon particle formation. Examples of the introduction of stabilizing groups into the MOF network that direct the loading and can influence the size and shape of the embedded particles are still rare and point into the possible direction of future investigations. Finally, the formation of bimetallic nanoparticles, which are stabilized and supported by a MOF network, will also be reviewed.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.444
Times cited: 366
DOI: 10.1002/ejic.201000473
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“Metal@COFs : covalent organic frameworks as templates for Pd nanoparticles and hydrogen storage properties of Pd@COF-102 hybrid material”. Kalidindi SB, Hyunchul O, Hirscher M, Esken D, Wiktor C, Turner S, Van Tendeloo G, Fischer RA, Chemistry: a European journal 18, 10848 (2012). http://doi.org/10.1002/chem.201201340
Abstract: Three-dimensional covalent organic frameworks (COFs) have been demonstrated as a new class of templates for nanoparticles. Photodecomposition of the [Pd(eta 3-C3H5)(eta 5-C5H5)]@COF-102 inclusion compound (synthesized by a gas-phase infiltration method) led to the formation of the Pd@COF-102 hybrid material. Advanced electron microscopy techniques (including high-angle annular dark-field scanning transmission electron microscopy and electron tomography) along with other conventional characterization techniques unambiguously showed that highly monodisperse Pd nanoparticles ((2.4 +/- 0.5) nm) were evenly distributed inside the COF-102 framework. The Pd@COF-102 hybrid material is a rare example of a metal-nanoparticle-loaded porous crystalline material with a very narrow size distribution without any larger agglomerates even at high loadings (30 wt %). Two samples with moderate Pd content (3.5 and 9.5 wt %) were used to study the hydrogen storage properties of the metal-decorated COF surface. The uptakes at room temperature from these samples were higher than those of similar systems such as Pd@metalorganic frameworks (MOFs). The studies show that the H2 capacities were enhanced by a factor of 2-3 through Pd impregnation on COF-102 at room temperature and 20 bar. This remarkable enhancement is not just due to Pd hydride formation and can be mainly ascribed to hydrogenation of residual organic compounds, such as bicyclopentadiene. The significantly higher reversible hydrogen storage capacity that comes from decomposed products of the employed organometallic Pd precursor suggests that this discovery may be relevant to the discussion of the spillover phenomenon in metal/MOFs and related systems.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 5.317
Times cited: 88
DOI: 10.1002/chem.201201340
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“Metal-polymer heterojunction in colloidal-phase plasmonic catalysis”. Rogolino A, Claes N, Cizaurre J, Marauri A, Jumbo-Nogales A, Lawera Z, Kruse J, Sanroman-Iglesias M, Zarketa I, Calvo U, Jimenez-Izal E, Rakovich YP, Bals S, Matxain JM, Grzelczak M, The journal of physical chemistry letters 13, 2264 (2022). http://doi.org/10.1021/ACS.JPCLETT.1C04242
Abstract: Plasmonic catalysis in the colloidal phase requires robust surface ligands that prevent particles from aggregation in adverse chemical environments and allow carrier flow from reagents to nanoparticles. This work describes the use of a water-soluble conjugated polymer comprising a thiophene moiety as a surface ligand for gold nanoparticles to create a hybrid system that, under the action of visible light, drives the conversion of the biorelevant NAD+ to its highly energetic reduced form NADH. A combination of advanced microscopy techniques and numerical simulations revealed that the robust metal-polymer heterojunction, rich in sulfonate functional groups, directs the interaction of electron-donor molecules with the plasmonic photocatalyst. The tight binding of polymer to the gold surface precludes the need for conventional transition-metal surface cocatalysts, which were previously shown to be essential for photocatalytic NAD(+) reduction but are known to hinder the optical properties of plasmonic nanocrystals. Moreover, computational studies indicated that the coating polymer fosters a closer interaction between the sacrificial electron-donor triethanolamine and the nanoparticles, thus enhancing the reactivity.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 5.7
Times cited: 1
DOI: 10.1021/ACS.JPCLETT.1C04242
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“Metal-assisted secondary ion mass spectrometry: the influence of Ag and Au deposition on molecular ion yields”. Adriaensen L, Vangaever F, Gijbels R, Analytical chemistry 76, 6777 (2004). http://doi.org/10.1021/ac049108d
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 6.32
Times cited: 67
DOI: 10.1021/ac049108d
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“Merging Metadynamics into Hyperdynamics: Accelerated Molecular Simulations Reaching Time Scales from Microseconds to Seconds”. Bal KM, Neyts EC, Journal of chemical theory and computation 11, 4545 (2015). http://doi.org/10.1021/acs.jctc.5b00597
Abstract: The hyperdynamics method is a powerful tool to simulate slow processes at the atomic level. However, the construction of an optimal hyperdynamics potential is a task that is far from trivial. Here, we propose a generally applicable implementation of the hyperdynamics algorithm, borrowing two concepts from metadynamics. First, the use of a collective variable (CV) to represent the accelerated dynamics gives the method a very large flexibility and simplicity. Second, a metadynamics procedure can be used to construct a suitable history-dependent bias potential on-the-fly, effectively turning the algorithm into a self-learning accelerated molecular dynamics method. This collective variable-driven hyperdynamics (CVHD) method has a modular design: both the local system properties on which the bias is based, as well as the characteristics of the biasing method itself, can be chosen to match the needs of the considered system. As a result, system-specific details are abstracted from the biasing algorithm itself, making it extremely versatile and transparent. The method is tested on three model systems: diffusion on the Cu(001) surface and nickel-catalyzed methane decomposition, as examples of reactive processes with a bond-length-based CV, and the folding of a long polymer-like chain, using a set of dihedral angles as a CV. Boost factors up to 109, corresponding to a time scale of seconds, could be obtained while still accurately reproducing correct dynamics.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 5.245
Times cited: 41
DOI: 10.1021/acs.jctc.5b00597
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“Melting temperatures and possible precursor plastic phases of CCl4and GeI4as a function of pressure”. Matthai CC, Lamoen D, March NH, Physics and chemistry of liquids 54, 130 (2016). http://doi.org/10.1080/00319104.2015.1068666
Abstract: The motivation for the present study is to be found in the recent experiments of Fuchizaki and Hamaya on GeI4. They observed a rapid increase in the melting temperature Tm in going from atmospheric pressure to p ~ 2.6 GPa. Tm was found to be largely independent of pressure above this value. In this paper, heuristic arguments are presented to support the idea that until some critical pressure, a crystalline phase of SnI4, CCl4 and GeI4 molecular solids melts into a low density liquid. However, at this critical pressure, a phase boundary intersects Tm(p), separating a low density liquid phase from a high density liquid. The new phase boundary is between the crystal and an amorphous molecular solid with increasing polymerisation as the pressure is increased.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.145
DOI: 10.1080/00319104.2015.1068666
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“Melting of partially fluorinated graphene : from detachment of fluorine atoms to large defects and random coils”. Singh SK, Costamagna S, Neek-Amal M, Peeters FM, The journal of physical chemistry: C : nanomaterials and interfaces 118, 4460 (2014). http://doi.org/10.1021/JP4109333
Abstract: The melting of fluorographene is very unusual and depends strongly on the degree of fluorination. For temperatures below 1000 K, fully fluorinated graphene (FFG) is thermomechanically more stable than graphene but at T-m approximate to 2800 K FFG transits to random coils which is almost 2 times lower than the melting temperature of graphene, i.e., 5300 K. For fluorinated graphene up to 30% ripples causes detachment of individual F-atoms around 2000 K, while for 40%-60% fluorination large defects are formed beyond 1500 K and beyond 60% of fluorination F-atoms remain bonded to graphene until melting. The results agree with recent experiments on the dependence of the reversibility of the fluorination process on the percentage of fluorination.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Impact Factor: 4.536
Times cited: 16
DOI: 10.1021/JP4109333
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“Mechanistic studies of gas reactions with multicomponent solids : what can we learn by combining NAP XPS and atomic resolution STEM/EDX?”.Sirotina AP, Callaert C, Volykhov AA, Frolov AS, Sanchez-Barriga J, Knop-Gericke A, Hadermann J, Yashina LV, The journal of physical chemistry: C : nanomaterials and interfaces 123, 26201 (2019). http://doi.org/10.1021/ACS.JPCC.9B05052
Abstract: Rapid development of experimental techniques has enabled real time studies of solid gas reactions at the level reaching the atomic scale. In the present paper, we focus on a combination of atomic resolution STEM/EDX, which visualizes the reaction zone, and near ambient pressure (NAP) XPS, which collects information for a surface layer of variable thickness under reaction conditions. We compare the behavior of two affined topological insulators, Bi2Te3 and Sb2Te3. We used a simple reaction with molecular oxygen occurring at 298 K, which is of practical importance to avoid material degradation. Despite certain limitations, a combination of in situ XPS and ex situ cross-sectional STEM/EDX allowed us to obtain a self-consistent picture of the solid gas reaction mechanism for oxidation of Sb2Te3 and Bi2Te3 crystals, which includes component redistribution between the oxide and the subsurface layer and Te segregation with formation of a thin ordered layer at the interface. The process is multistep in case of both compounds. At the very beginning of the oxidation process the reactivity is determined by the energy benefit of the corresponding element oxygen bond formation. Further in the oxidation process, the behavior of these two compounds becomes similar and features component redistribution between the oxide and the subsurface layer.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 4.536
DOI: 10.1021/ACS.JPCC.9B05052
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“Mechanistic Insight into the Photocatalytic Working of Fluorinated Anatase {001} Nanosheets”. Kus M, Altantzis T, Vercauteren S, Caretti I, Leenaerts O, Batenburg KJ, Mertens M, Meynen V, Partoens B, Van Doorslaer S, Bals S, Cool P, The journal of physical chemistry: C : nanomaterials and interfaces 121, 26275 (2017). http://doi.org/10.1021/acs.jpcc.7b05586
Abstract: Anatase nanosheets with exposed {001} facets
have gained increasing interest for photocatalytic applications. To
fully understand the structure-to-activity relation, combined
experimental and computational methods have been exploited.
Anatase nanosheets were prepared under hydrothermal conditions
in the presence of fluorine ions. High resolution scanning
transmission electron microscopy was used to fully characterize
the synthesized material, confirming the TiO2 nanosheet
morphology. Moreover, the surface structure and composition
of a single nanosheet could be determined by annular bright-field
scanning transmission electron microscopy (ABF-STEM) and
STEM electron energy loss spectroscopy (STEM-EELS). The photocatalytic activity was tested for the decomposition of organic
dyes rhodamine 6G and methyl orange and compared to a reference TiO2 anatase sample. The anatase nanosheets with exposed
{001} facets revealed a significantly lower photocatalytic activity compared to the reference. In order to understand the
mechanism for the catalytic performance, and to investigate the role of the presence of F−, light-induced electron paramagnetic
resonance (EPR) experiments were performed. The EPR results are in agreement with TEM, proving the presence of Ti3+
species close to the surface of the sample and allowing the analysis of the photoinduced formation of paramagnetic species.
Further, ab initio calculations of the anisotropic effective mass of electrons and electron holes in anatase show a very high effective
mass of electrons in the [001] direction, having a negative impact on the mobility of electrons toward the {001} surface and thus
the photocatalysis. Finally, motivated by the experimental results that indicate the presence of fluorine atoms at the surface, we
performed ab initio calculations to determine the position of the band edges in anatase slabs with different terminations of the
{001} surface. The presence of fluorine atoms near the surface is shown to strongly shift down the band edges, which indicates
another reason why it can be expected that the prepared samples with a large amount of {001} surface, but with fluorine atoms
near the surface, show only a low photocatalytic activity.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT); Laboratory of adsorption and catalysis (LADCA)
Impact Factor: 4.536
Times cited: 20
DOI: 10.1021/acs.jpcc.7b05586
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