“Two-dimensional halide Pb-perovskite-double perovskite epitaxial heterostructures”. Singh A, Yuan B, Rahman MH, Yang H, De A, Park JY, Zhang S, Huang L, Mannodi-Kanakkithodi A, Pennycook TJ, Dou L, Journal of the American Chemical Society 145, 19885 (2023). http://doi.org/10.1021/JACS.3C06127
Abstract: Epitaxial heterostructures of two-dimensional (2D) halide perovskites offer a new platform for studying intriguing structural, optical, and electronic properties. However, difficulties with the stability of Pb- and Sn-based heterostructures have repeatedly slowed the progress. Recently, Pb-free halide double perovskites are gaining a lot of attention due to their superior stability and greater chemical diversity, but they have not been successfully incorporated into epitaxial heterostructures for further investigation. Here, we report epitaxial core-shell heterostructures via growing Pb-free double perovskites (involving combinations of Ag(I)-Bi(III), Ag-Sb, Ag-In, Na-Bi, Na-Sb, and Na-In) around Pb perovskite 2D crystals. Distinct from Pb-Pb and Pb-Sn perovskite heterostructures, growths of the Pb-free shell at 45 degrees on the (100) surface of the lead perovskite core are observed in all Pb-free cases. The in-depth structural analysis carried out with electron diffraction unequivocally demonstrates the growth of the Pb-free shell along the [110] direction of the Pb perovskite, which is likely due to the relatively lower surface energy of the (110) surface. Furthermore, an investigation of anionic interdiffusion across heterostructure interfaces under the influence of heat was carried out. Interestingly, halide anion diffusion in the Pb-free 2D perovskites is found to be significantly suppressed as compared to Pb-based 2D perovskites. The great structural tunability and excellent stability of Pb-free perovskite heterostructures may find uses in electronic and optoelectronic devices in the near future.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 15
DOI: 10.1021/JACS.3C06127
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“Hematite iron oxide nanorod patterning inside COK-12 mesochannels as an efficient visible light photocatalyst”. Wee LH, Meledina M, Turner S, Custers K, Kerkhofs S, Van Tendeloo G, Martens JA, Journal of materials chemistry A : materials for energy and sustainability 3, 19884 (2015). http://doi.org/10.1039/C5TA05075H
Abstract: The uniform dispersion of functional oxide nanoparticles on the walls of ordered mesoporous silica to tailor optical, electronic, and magnetic properties for biomedical and environmental applications is a scientific challenge. Here, we demonstrate homogeneous confined growth of 5 nanometer-sized hematite iron oxide (α-Fe2O3) inside mesochannels of ordered mesoporous COK-12 nanoplates. The three-dimensional inclusion of the α-Fe2O3 nanorods in COK-12 particles is studied using high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM), energy-dispersive X-ray (EDX) spectroscopy and electron tomography. High resolution imaging and EDX spectroscopy provide information about the particle size, shape and crystal phase of the loaded α-Fe2O3 material, while electron tomography provides detailed information on the spreading of the nanorods throughout the COK-12 host. This nanocomposite material, having a semiconductor band gap energy of 2.40 eV according to diffuse reflectance spectroscopy, demonstrates an improved visible light photocatalytic degradation activity with rhodamine 6G and 1-adamantanol model compounds.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 8.867
Times cited: 9
DOI: 10.1039/C5TA05075H
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“Exploring machine learning methods for absolute configuration determination with vibrational circular dichroism”. Vermeyen T, Brence J, Van Echelpoel R, Aerts R, Acke G, Bultinck P, Herrebout W, Physical Chemistry Chemical Physics 23, 19781 (2021). http://doi.org/10.1039/D1CP02428K
Abstract: The added value of supervised Machine Learning (ML) methods to determine the Absolute Configuration (AC) of compounds from their Vibrational Circular Dichroism (VCD) spectra was explored. Among all ML methods considered, Random Forest (RF) and Feedforward Neural Network (FNN) yield the best performance for identification of the AC. At its best, FNN allows near-perfect AC determination, with accuracy of prediction up to 0.995, while RF combines good predictive accuracy (up to 0.940) with the ability to identify the spectral areas important for the identification of the AC. No loss in performance of either model is observed as long as the spectral sampling interval used does not exceed the spectral bandwidth. Increasing the sampling interval proves to be the best method to lower the dimensionality of the input data, thereby decreasing the computational cost associated with the training of the models.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Molecular Spectroscopy (MolSpec)
Impact Factor: 4.123
DOI: 10.1039/D1CP02428K
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“Structural, electrochemical and magnetic properties of a novel KFeSO4F polymorph”. Lander L, Rousse G, Abakumov AM, Sougrati M, Van Tendeloo G, Tarascon J-M, Journal of materials chemistry A : materials for energy and sustainability 3, 19754 (2015). http://doi.org/10.1039/c5ta05548b
Abstract: In the quest for sustainable and low-cost positive electrode materials for Li-ion batteries, we discovered, as reported herein, a new low temperature polymorph of KFeSO4F. Contrary to the high temperature phase crystallizing in a KTiOPO4-like structure, this new phase adopts a complex layer-like structure built on FeO4F2 octahedra and SO4 tetrahedra, with potassium cations located in between the layers, as solved using neutron and synchrotron diffraction experiments coupled with electron diffraction. The detailed analysis of the structure reveals an alternation of edge-and corner-shared FeO4F2 octahedra leading to a large monoclinic cell of 1771.774(7) angstrom(3). The potassium atoms are mobile within the structure as deduced by ionic conductivity measurements and confirmed by the bond valence energy landscape approach thus enabling a partial electrochemical removal of K+ and uptake of Li+ at an average potential of 3.7 V vs. Li+/Li-0. Finally, neutron diffraction experiments coupled with SQUID measurements reveal a long range antiferromagnetic ordering of the Fe2+ magnetic moments below 22 K with a possible magnetoelectric behavior.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 8.867
Times cited: 11
DOI: 10.1039/c5ta05548b
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“High-throughput computational screening of 2D materials for thermoelectrics”. Sarikurt S, Kocabas T, Sevik C, Journal Of Materials Chemistry A 8, 19674 (2020). http://doi.org/10.1039/D0TA04945J
Abstract: High-performance thermoelectric materials are critical in recuperating the thermal losses in various machinery and promising in renewable energy applications. In this respect, the search for novel thermoelectric materials has attracted considerable attention. In particular, low dimensional materials have been proposed as potential candidates due to their unique and controllable thermal and electronic transport properties. The considerable potential of several two-dimensional materials as thermoelectric devices has already been uncovered and many new candidates that merit further research have been suggested. In this regard, we comprehensively investigate the thermoelectric coefficients and electronic fitness function (EFF) of a large family of structurally isotropic and anisotropic two-dimensional layered materials using density functional theory combined with semi-classical Boltzmann transport theory. With this high-throughput screening, we bring to light additional 2D crystals that haven't been previously classified as favorable TE materials. We predict that Pb2Se2, GeS2, As-2, NiS2, Hf2O6, Zr2O6, AsBrS, ISbTe, ISbSe, AsISe, and AsITe are promising isotropic thermoelectric materials due to their considerably high EFF values. In addition to these materials, Hf2Br4, Zr2Br4, Hf2Cl4, Zr2Cl4, Hf2O6, Zr(2)O(6)and Os(2)O(4)exhibit strong anisotropy and possess prominently high EFF values.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Impact Factor: 11.9
DOI: 10.1039/D0TA04945J
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“Hybrid magnetic-plasmonic nanoparticle probes for multimodal bioimaging”. dela Encarnacion C, Lenzi E, Henriksen-Lacey M, Molina B, Jenkinson K, Herrero A, Colas L, Ramos-Cabrer P, Toro-Mendoza J, Orue I, Langer J, Bals S, Jimenez de Aberasturi D, Liz-Marzan LM, The journal of physical chemistry: C : nanomaterials and interfaces 126, 19519 (2022). http://doi.org/10.1021/ACS.JPCC.2C06299
Abstract: Multimodal contrast agents, which take advantage of different imaging modalities, have emerged as an interesting approach to overcome the technical limitations of individual techniques. We developed hybrid nanoparticles comprising an iron oxide core and an outer gold spiky layer, stabilized by a biocompatible polymeric shell. The combined magnetic and optical properties of the different components provide the required functionalities for magnetic resonance imaging (MRI), surface-enhanced Raman scattering (SERS), and fluorescence imaging. The fabrication of such hybrid nanoprobes comprised the adsorption of small gold nanoparticles onto premade iron oxide cores, followed by controlled growth of spiky gold shells. The gold layer thickness and branching degree (tip sharpness) can be controlled by modifying both the density of Au nanoparticle seeds on the iron oxide cores and the subsequent nanostar growth conditions. We additionally demonstrated the performance of these hybrid multifunctional nanoparticles as multimodal contrast agents for correlative imaging of in vitro cell models and ex vivo tissues.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 3.7
Times cited: 10
DOI: 10.1021/ACS.JPCC.2C06299
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“Atomic layer deposition of ruthenium on a titanium nitride surface : a density functional theory study”. Phung QM, Vancoillie S, Pourtois G, Swerts J, Pierloot K, Delabie A, The journal of physical chemistry: C : nanomaterials and interfaces 117, 19442 (2013). http://doi.org/10.1021/jp405489w
Abstract: Because of its excellent properties in nanotechnology applications, atomic layer deposition of ruthenium (Ru) has been the subject of numerous experimental studies. Recently, two different Ru precursors were compared for plasma-enhanced atomic layer deposition (PEALD) of Ru, and their reactivity was found to be different. Inhibition was observed for bis(ethylcyclopentadienyl)ruthenium (Ru(EtCp)(2)), while nearly linear growth behavior was observed for (methylcyclopentadienyl-pyrrolyl)ruthenium (Ru(MeCp)Py). To understand this difference in reactivity, we investigate the adsorption of RuCp, and RuCpPy (i.e., without substituents) on a TiN surface using calculations based on periodic boundary conditions density functional theory (DFT) combined with experiments based on Rutherford backscattering spectroscopy (RBS). The calculations demonstrate that the RuCpPy precursor chemisorbs on the TiN(100) surface while the RuCp2 precursor only physisorbs. We propose a reaction mechanism for the chemisorption of RuCpPy. The area density of the calculated RuCpPy surface species is compared with the experimental values from RBS. The impact of a H-plasma is also investigated. The DFT calculations and experimental results from RBS provide insight into the adsorption processes of the RuCpPy and RuCp2 precursors on the TiN(100) surface.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.536
Times cited: 6
DOI: 10.1021/jp405489w
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“F-doped Co3O4 photocatalysts for sustainable H2 generation from water/ethanol”. Gasparotto A, Barreca D, Bekermann D, Devi A, Fischer RA, Fornasiero P, Gombac V, Lebedev OI, Maccato C, Montini T, Van Tendeloo G, Tondello E, Journal of the American Chemical Society 133, 19362 (2011). http://doi.org/10.1021/ja210078d
Abstract: p-Type Co3O4 nanostructured films are synthesized by a plasma-assisted process and tested in the photocatalytic production of H2 from water/ethanol solutions under both near-UV and solar irradiation. It is demonstrated that the introduction of fluorine into p-type Co3O4 results in a remarkable performance improvement with respect to the corresponding undoped oxide, highlighting F-doped Co3O4 films as highly promising systems for hydrogen generation. Notably, the obtained yields were among the best ever reported for similar semiconductor-based photocatalytic processes.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 13.858
Times cited: 114
DOI: 10.1021/ja210078d
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“How membrane lipids influence plasma delivery of reactive oxygen species into cells and subsequent DNA damage : an experimental and computational study”. Van der Paal J, Hong S-H, Yusupov M, Gaur N, Oh J-S, Short RD, Szili EJ, Bogaerts A, Physical chemistry, chemical physics 21, 19327 (2019). http://doi.org/10.1039/C9CP03520F
Abstract: The mechanisms of plasma in medicine are broadly attributed to plasma-derived reactive oxygen and nitrogen species (RONS). In order to exert any intracellular effects, these plasma-derived RONS must first traverse a major barrier in the cell membrane. The cell membrane lipid composition, and thereby the magnitude of this barrier, is highly variable between cells depending on type and state (e.g. it is widely accepted that healthy and cancerous cells have different membrane lipid compositions). In this study, we investigate how plasma-derived RONS interactions with lipid membrane components can potentially be exploited in the future for treatment of diseases. We couple phospholipid vesicle experiments, used as simple cell models, with molecular dynamics (MD) simulations of the lipid membrane to provide new insights into how the interplay between phospholipids and cholesterol may influence the response of healthy and diseased cell membranes to plasma-derived RONS. We focus on the (i) lipid tail saturation degree, (ii) lipid head group type, and (iii) membrane cholesterol fraction. Using encapsulated molecular probes, we study the influence of the above membrane components on the ingress of RONS into the vesicles, and subsequent DNA damage. Our results indicate that all of the above membrane components can enhance or suppress RONS uptake, depending on their relative concentration within the membrane. Further, we show that higher RONS uptake into the vesicles does not always correlate with increased DNA damage, which is attributed to ROS reactivity and lifetime. The MD simulations indicate the multifactorial chemical and physical processes at play, including (i) lipid oxidation, (ii) lipid packing, and (iii) lipid rafts formation. The methods and findings presented here provide a platform of knowledge that could be leveraged in the development of therapies relying on the action of plasma, in which the cell membrane and oxidative stress response in cells is targeted.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.123
Times cited: 1
DOI: 10.1039/C9CP03520F
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“First-principles investigation of bilayer fluorographene”. Sivek J, Leenaerts O, Partoens B, Peeters FM, The journal of physical chemistry: C : nanomaterials and interfaces 116, 19240 (2012). http://doi.org/10.1021/jp3027012
Abstract: Ab initio calculations within the density functional theory formalism are performed to investigate the stability and electronic properties of fluorinated bilayer graphene (bilayer fluorographene). A comparison is made to previously investigated graphane, bilayer graphane, and fluorographene. Bilayer fluorographene is found to be a much more stable material than bilayer graphane. Its electronic band structure is similar to that of monolayer fluorographene, but its electronic band gap is significantly larger (about 1 eV). We also calculate the effective masses around the Gamma-point for fluorographene and bilayer fluorographene and find that they are isotropic, in contrast to earlier reports. Furthermore, it is found that bilayer fluorographene is almost as strong as graphene, as its 2D Young's modulus is approximately 300 N m(-1).
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Impact Factor: 4.536
Times cited: 39
DOI: 10.1021/jp3027012
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“Approaches to calculation of exciton interaction energies for a molecular dimer”. Howard IA, Zutterman F, Deroover G, Lamoen D, van Alsenoy C, Journal Of Physical Chemistry B 108, 19155 (2004). http://doi.org/10.1021/jp040417h
Keywords: A1 Journal article; Electron Microscopy for Materials Science (EMAT);
Impact Factor: 3.177
Times cited: 35
DOI: 10.1021/jp040417h
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“A DFT study of H-dissolution into the bulk of a crystalline Ni(111) surface: a chemical identifier for the reaction kinetics”. Shirazi M, Bogaerts A, Neyts EC, Physical chemistry, chemical physics 19, 19150 (2017). http://doi.org/10.1039/C7CP03662K
Abstract: In this study, we investigated the diffusion of H-atoms to the subsurface and their further diffusion into the bulk of a Ni(111) crystal by means of density functional theory calculations in the context of thermal and plasma-assisted catalysis. The H-atoms at the surface can originate from the dissociative adsorption of H2 or CH4 molecules, determining the surface H-coverage. When a threshold H-coverage is passed, corresponding to 1.00 ML for the crystalline Ni(111) surface, the surface-bound H-atoms start to diffuse to the subsurface. A similar threshold coverage is observed for the interstitial H-coverage. Once the interstitial sites are filled up with a coverage above 1.00 ML of H, dissolution of interstitial H-atoms to the layer below the interstitial sites will be initiated. Hence, by applying a high pressure or inducing a reactive plasma and high temperature, increasing the H-flux to the surface, a large amount of hydrogen can diffuse in a crystalline metal like Ni and can be absorbed. The formation of metal hydride may modify the entire reaction kinetics of the system. Equivalently, the H-atoms in the bulk can easily go back to the surface and release a large amount of heat. In a plasma process, H-atoms are formed in the plasma, and therefore the energy barrier for dissociative adsorption is dismissed, thus allowing achievement of the threshold coverage without applying a high pressure as in a thermal process. As a result, depending on the crystal plane and type of metal, a large number of H-atoms can be dissolved (absorbed) in the metal catalyst, explaining the high efficiency of plasma-assisted catalytic reactions. Here, the mechanism of H-dissolution is established as a chemical identifier for the investigation of the reaction kinetics of a chemical process.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.123
Times cited: 10
DOI: 10.1039/C7CP03662K
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“Predicting the surface plasmon resonance wavelength of gold-silver alloy nanoparticles”. Verbruggen SW, Keulemans M, Martens JA, Lenaerts S, The journal of physical chemistry: C : nanomaterials and interfaces 117, 19142 (2013). http://doi.org/10.1021/JP4070856
Abstract: Gold-silver alloy nanoparticles display surface plasmon resonance (SPR) over a broad range of the UV-vis spectrum. We propose a model to predict the SPR wavelength of gold-silver alloy colloids based on the combined effect of alloy composition and particle size. The SPR wavelength is derived from extinction spectra simulated using available experimental dielectric constant data and accounts for particle size by applying Mie theory. Comparison of calculated values with experimental data evidences the accuracy of the model. The new SPR wavelength estimation tool will be of particular interest for developing dedicated bimetallic plasmonic nanostructures.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 4.536
Times cited: 51
DOI: 10.1021/JP4070856
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“3D porous nanostructured platinum prepared using atomic layer deposition”. Pulinthanathu Sree S, Dendooven J, Geerts L, Ramachandran RK, Javon E, Ceyssens F, Breynaert E, Kirschhock CEA, Puers R, Altantzis T, Van Tendeloo G, Bals S, Detavernier C, Martens JA, Journal of materials chemistry A : materials for energy and sustainability 5, 19007 (2017). http://doi.org/10.1039/C7TA03257A
Abstract: A robust and easy to handle 3D porous platinum structure was created via replicating the 3D channel system
of an ordered mesoporous silica material using atomic layer deposition (ALD) over micrometer distances.
After ALD of Pt in the silica material, the host template was digested using hydrogen fluoride (HF). A fully
connected ordered Pt nanostructure was obtained with morphology and sizes corresponding to that of
the pores of the host matrix, as revealed with high-resolution scanning transmission electron
microscopy and electron tomography. The Pt nanostructure consisted of hexagonal Pt rods originating
from the straight mesopores (11 nm) of the host structure and linking features resulting from Pt
replication of the interconnecting mesopore segments (2–4 nm) present in the silica host structure.
Electron tomography of partial replicas, made by incomplete infilling of Zeotile-4 material with Pt,
provided insight in the connectivity and formation mechanism of the Pt nanostructure by ALD. The Pt
replica was evaluated for its potential use as electrocatalyst for the hydrogen evolution reaction, one of
the half-reactions of water electrolysis, and as microelectrode for biomedical sensing. The Pt replica
showed high activity for the hydrogen evolution reaction and electrochemical characterization revealed
a large impedance improvement in comparison with reference Pt electrodes.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 8.867
Times cited: 9
DOI: 10.1039/C7TA03257A
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“Electrochemical evidence for neuroglobin activity on NO at physiological concentrations”. Trashin S, De Jong M, Luyckx E, Dewilde S, De Wael K, Journal of biological chemistry 291, 18959 (2016). http://doi.org/10.1074/JBC.M116.730176
Abstract: The true function of neuroglobin (Ngb) and, particularly, human Ngb (NGB) has been under debate since its discovery 15 years ago. It has been expected to play a role in oxygen binding/supply, but a variety of other functions have been put forward, including NO dioxygenase activity. However, in vitro studies that could unravel these potential roles have been hampered by the lack of an Ngb-specific reductase. In this work, we used electrochemical measurements to investigate the role of an intermittent internal disulfide bridge in determining NO oxidation kinetics at physiological NO concentrations. The use of a polarized electrode to efficiently interconvert the ferric (Fe3+) and ferrous (Fe2+) forms of an immobilized NGB showed that the disulfide bridge both defines the kinetics of NO dioxygenase activity and regulates appearance of the free ferrous deoxy-NGB, which is the redox active form of the protein in contrast to oxy-NGB. Our studies further identified a role for the distal histidine, interacting with the hexacoordinated iron atom of the heme, in oxidation kinetics. These findings may be relevant in vivo, for example in blocking apoptosis by reduction of ferric cytochrome c, and gentle tuning of NO concentration in the tissues.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 4.125
Times cited: 11
DOI: 10.1074/JBC.M116.730176
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“Novel two-dimensional AlSb and InSb monolayers with a double-layer honeycomb structure : a first-principles study”. Bafekry A, Faraji M, Fadlallah MM, Jappor HR, Karbasizadeh S, Ghergherehchi M, Sarsari IA, Ziabari AA, Physical Chemistry Chemical Physics 23, 18752 (2021). http://doi.org/10.1039/D1CP02590B
Abstract: In this work, motivated by the fabrication of an AlSb monolayer, we have focused on the electronic, mechanical and optical properties of AlSb and InSb monolayers with double-layer honeycomb structures, employing the density functional theory approach. The phonon band structure and cohesive energy confirm the stability of the XSb (X = Al and In) monolayers. The mechanical properties reveal that the XSb monolayers have a brittle nature. Using the GGA + SOC (HSE + SOC) functionals, the bandgap of the AlSb monolayer is predicted to be direct, while InSb has a metallic character using both functionals. We find that XSb (X = Al, In) two-dimensional bodies can absorb ultraviolet light. The present findings suggest several applications of AlSb and InSb monolayers in novel optical and electronic usages.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 4.123
DOI: 10.1039/D1CP02590B
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“DFT and microkinetic comparison of ru-doped porphyrin-like graphene and nanotubes toward catalytic formic acid decomposition and formation”. Nematollahi P, Ma H, Schneider WF, Neyts EC, Journal Of Physical Chemistry C 125, 18673 (2021). http://doi.org/10.1021/ACS.JPCC.1C03914
Abstract: Immobilization of single metal atoms on a solid host opens numerous possibilities for catalyst designs. If that host is a two-dimensional sheet, sheet curvature becomes a design parameter potentially complementary to host and metal composition. Here, we use a combination of density functional theory calculations and microkinetic modeling to compare the mechanisms and kinetics of formic acid decomposition and formation, chosen for their relevance as a potential hydrogen storage medium, over single Ru atoms anchored to pyridinic nitrogen in a planar graphene flake (RuN4-G) and curved carbon nanotube (RuN4-CNT). Activation barriers are lowered and the predicted turnover frequencies are increased over RuN4-CNT relative to RuN4-CNT. The results highlight the potential of curvature control as a means to achieve high performance and robust catalysts.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.536
DOI: 10.1021/ACS.JPCC.1C03914
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“A first-principles study of stable few-layer penta-silicene”. Aierken Y, Leenaerts O, Peeters FM, Physical chemistry, chemical physics 18, 18486 (2016). http://doi.org/10.1039/c6cp03200a
Abstract: Recently penta-graphene was proposed as a stable two-dimensional carbon allotrope consisting of a single layer of interconnected carbon pentagons [Zhang et al., PNAS, 2015, 112, 2372]. Its silicon counterpart, penta-silicene, however, is not stable. In this work, we show that multilayers of penta-silicene form stable materials with semiconducting or metallic properties, depending on the stacking mode. We demonstrate their dynamic stability through their phonon spectrum and using molecular dynamics. A particular type of bilayer penta-silicene is found to have lower energy than all of the known hexagonal silicene bilayers and forms therefore the most stable bilayer silicon material predicted so far. The electronic and mechanical properties of these new silicon allotropes are studied in detail and their behavior under strain is investigated. We demonstrate that strain can be used to tune its band gap.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 4.123
Times cited: 42
DOI: 10.1039/c6cp03200a
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“Plasma-Based CO2Conversion: To Quench or Not to Quench?”.Vermeiren V, Bogaerts A, Journal Of Physical Chemistry C 124, 18401 (2020). http://doi.org/10.1021/acs.jpcc.0c04257
Abstract: Plasma technology is gaining increasing interest for CO2 conversion. The gas temperature in (and after) the plasma reactor largely affects the performance. Therefore, we examine the effect of cooling/quenching, during and after the plasma, on the CO2 conversion and energy efficiency, for typical “warm” plasmas, by means of chemical kinetics modeling. For plasmas at low specific energy input (SEI ∼ 0.5 eV/molecule), it is best to quench at the plasma end, while for high-SEI plasmas (SEI ∼ 4 eV/molecule), quenching at maximum conversion is better. For low-SEI plasmas, quenching can even increase the conversion beyond the dissociation in the plasma, known as superideal quenching. To better understand the effects of quenching at different plasma conditions, we study the dissociation and recombination rates, as well as the vibrational distribution functions (VDFs) of CO2, CO, and O2. When a high vibrational−translational (VT) nonequilibrium exists at the moment of quenching, the dissociation and recombination reaction rates both increase. Depending on the conversion degree at the moment of quenching, this can lead to a net increase or decrease of CO2 conversion. In general, however, and certainly for equilibrium plasmas at high temperature, quenching after the plasma helps prevent recombination reactions and clearly enhances the final CO2 conversion. We also investigate the effect of different quenching cooling rates on the CO2 conversion and energy efficiency. Finally, we compare plasma-based conversion to purely thermal conversion. For warm plasmas with typical temperatures of 3000−4000 K, the conversion is roughly thermal.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.7
DOI: 10.1021/acs.jpcc.0c04257
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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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“Understanding and promoting the rapid preparation of the triplite-phase of LiFeSO4F for use as a large-potential Fe cathode”. Ati M, Sathiya M, Boulineau S, Reynaud M, Abakumov A, Rousse G, Melot B, Van Tendeloo G, Tarascon J-M, Journal of the American Chemical Society 134, 18380 (2012). http://doi.org/10.1021/ja3074402
Abstract: The development of new electrode materials, which are composed of Earth-abundant elements and that can be made via eco-efficient processes, is becoming absolutely necessary for reasons of sustainable production. The 3.9 V triplite-phase of LiFeSO4F, compared to the 3.6 V tavorite-phase, could satisfy this requirement provided the currently complex synthetic pathway can be simplified. Here, we present our work aiming at better understanding the reaction mechanism that govern its formation as a way to optimize its preparation. We first demonstrate, using complementary X-ray diffraction and transmission electron microscopy studies, that triplite-LiFeSO4F can nucleate from tavorite-LiFeSO4F via a reconstructive process whose kinetics are significantly influenced by moisture and particle morphology. Perhaps the most spectacular finding is that it is possible to prepare electrochemically active triplite-LiFeSO4F from anhydrous precursors using either reactive spark plasma sintering (SPS) synthesis in a mere 20 min at 320 degrees C or room temperature ball milling for 3 h. These new pathways appear to be strongly driven by the easy formation of a disordered phase with higher entropy, as both techniques trigger disorder via rapid annealing steps or defect creation. Although a huge number of phases adopts the tavorite structure-type, this new finding offers both a potential way to prepare new compositions in the triplite structure and a wealth of opportunities for the synthesis of new materials which could benefit many domains beyond energy storage.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 13.858
Times cited: 36
DOI: 10.1021/ja3074402
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“Chemical mapping of the degradation of geranium lake in paint cross sections by MALDI-MSI”. Alvarez-Martin A, Quanico J, Scovacricchi T, Avranovich Clerici E, Baggerman G, Janssens K, Analytical chemistry 95, 18215 (2023). http://doi.org/10.1021/ACS.ANALCHEM.3C03992
Abstract: Matrix assisted laser desorption ionization-mass spectrometry imaging (MALDI-MSI) has become a powerful method to extract spatially resolved chemical information in complex materials. This study provides the first use of MALDI-MSI to define spatial–temporal changes in oil paints. Due to the highly heterogeneous nature of oil paints, the sample preparation had to be optimized to prevent molecules from delocalizing. Here, we present a new protocol for the layer-specific analysis of oil paint cross sections achieving a lateral resolution of 10 μm and without losing ionization efficiency due to topographic effects. The efficacy of this method was investigated in oil paint samples containing a mixture of two historic organic pigments, geranium lake and lead white, a mixture often employed in the work of painter Vincent Van Gogh. This methodology not only allows for spatial visualization of the molecules responsible for the pink hue of the paint but also helps to elucidate the chemical changes behind the discoloration of paintings with this composition. The results demonstrate that this approach provides valuable molecular compositional information about the degradation pathways of pigments in specific paint layers and their interaction with the binding medium and other paint components and with light over time. Since a spatial correlation between molecular species and the visual pattern of the discoloration pattern can be made, we expect that mass spectrometry imaging will become highly relevant in future degradation studies of many more historical pigments and paints.
Keywords: A1 Journal article; Antwerp X-ray Imaging and Spectroscopy (AXIS); Ecosphere
Impact Factor: 7.4
DOI: 10.1021/ACS.ANALCHEM.3C03992
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“Ordered and disordered packing of coronene molecules in carbon nanotubes”. Verberck B, Okazaki T, Tarakina NV, Physical chemistry, chemical physics 15, 18108 (2013). http://doi.org/10.1039/c3cp52797b
Abstract: Monte Carlo simulations of coronene molecules in single-walled carbon nanotubes (SWCNTs) and dicoronylene molecules in SWCNTs are performed. Depending on the diameter D of the encapsulating SWCNT, regimes favoring the formation of ordered, one-dimensional (1D) stacks of tilted molecules (D <= 1.7 nm for coronene@SWCNT, 1.5 nm <= D <= 1.7 nm for dicoronylene@SWCNT) and regimes with disordered molecular arrangements and increased translational mobilities enabling the thermally induced polymerization of neighboring molecules resulting in the formation of graphene nanoribbons (GNRs) are observed. The results show that the diameter of the encapsulating nanotube is a crucial parameter for the controlled synthesis of either highly ordered 1D structures or GNR precursors.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 4.123
Times cited: 9
DOI: 10.1039/c3cp52797b
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“Origin of the extra capacity in nitrogen-doped porous carbon nanofibers for high-performance potassium ion batteries”. Liu F, Meng J, Xia F, Liu Z, Peng H, Sun C, Xu L, Van Tendeloo G, Mai L, Wu J, Journal Of Materials Chemistry A 8, 18079 (2020). http://doi.org/10.1039/D0TA05626J
Abstract: While graphite has limited capacity as an anode material for potassium-ion batteries, nitrogen-doped carbon materials are more promising as extra capacity can usually be produced. However, the mechanism behind the origin of the extra capacity remains largely unclear. Here, the potassium storage mechanisms have been systematically studied in freestanding and porous N-doped carbon nanofibers with an additional similar to 100 mA h g(-1)discharge capacity at 0.1 A g(-1). The extra capacity is generated in the whole voltage window range from 0.01 to 2 V, which corresponds to both surface/interface K-ion absorptions due to the pyridinic N and pyrrolic N induced atomic vacancies and layer-by-layer intercalation due to the effects of graphitic N. As revealed by transmission electron microscopy, the N-doped samples have a clear and enhanced K-intercalation reaction. Theoretical calculations confirmed that the micropores with pyridinic N and pyrrolic N provide extra sites to form bonds with K, resulting in the extra capacity at high voltage. The chemical absorption of K-ions occurring inside the defective graphitic layer will prompt fast diffusion of K-ions and full realization of the intercalation capacity at low voltage. The approach of preparing N-doped carbon-based materials and the mechanism revealed by this work provide directions for the development of advanced materials for efficient energy storage.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 11.9
Times cited: 2
DOI: 10.1039/D0TA05626J
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“Spatial separation of covalent, ionic, and metallic interactions in Mg11Rh18B8 and Mg3Rh5B3”. Alekseeva AM, Abakumov AM, Leither-Jasper A, Schnelle W, Prots Y, Van Tendeloo G, Antipov EV, Grin Y, Chemistry: a European journal 19, 17860 (2013). http://doi.org/10.1002/chem.201301512
Abstract: The crystal structures of Mg11Rh18B8 and Mg3Rh5B3 have been investigated by using single-crystal X-ray diffraction. Mg11Rh18B8: space group P4/mbm; a=17.9949(7), c=2.9271(1)angstrom; Z=2. Mg3Rh5B3: space group Pmma; a=8.450(2), b=2.8644(6), c=11.602(2)angstrom; Z=2. Both crystal structures are characterized by trigonal prismatic coordination of the boron atoms by rhodium atoms. The [BRh6] trigonal prisms form arrangements with different connectivity patterns. Analysis of the chemical bonding by means of the electron-localizability/electron-density approach reveals covalent BRh interactions in these arrangements and the formation of BRh polyanions. The magnesium atoms that are located inside the polyanions interact ionically with their environment, whereas, in the structure parts, which are mainly formed by Mg and Rh atoms, multicenter (metallic) interactions are observed. Diamagnetic behavior and metallic electron transport of the Mg11Rh18B8 and Mg3Rh5B3 phases are in agreement with the bonding picture and the band structure.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 5.317
Times cited: 5
DOI: 10.1002/chem.201301512
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“High throughput first-principles calculations of bixbyite oxides for TCO applications”. Sarmadian N, Saniz R, Partoens B, Lamoen D, Volety K, Huyberechts G, Paul J, Physical chemistry, chemical physics 16, 17724 (2014). http://doi.org/10.1039/c4cp02788d
Abstract: We present a high-throughput computing scheme based on density functional theory (DFT) to generate a class of oxides and screen them with the aim of identifying those that might be electronically appropriate for transparent conducting oxide (TCO) applications. The screening criteria used are a minimum band gap to ensure sufficient transparency, a band edge alignment consistent with easy n- or p-type dopability, and a minimum thermodynamic phase stability to be experimentally synthesizable. Following this scheme we screened 23 binary and 1518 ternary bixbyite oxides in order to identify promising candidates, which can then be a subject of an in-depth study. The results for the known TCOs are in good agreement with the reported data in the literature. We suggest a list of several new potential TCOs, including both n- and p-type compounds.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
Impact Factor: 4.123
Times cited: 23
DOI: 10.1039/c4cp02788d
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“Improving the Energy Efficiency of CO2Conversion in Nonequilibrium Plasmas through Pulsing”. Vermeiren V, Bogaerts A, The journal of physical chemistry: C : nanomaterials and interfaces 123, 17650 (2019). http://doi.org/10.1021/acs.jpcc.9b02362
Abstract: Nonequilibrium plasmas offer a pathway for energy-efficient CO2 conversion through vibrationally induced dissociation. However, the efficiency of this pathway is limited by a rise in gas temperature, which increases vibrational−translational (VT) relaxation and quenches the vibrational levels. Therefore, we investigate here the effect of plasma pulsing on the VT nonequilibrium and on the CO2 conversion by means of a zerodimensional chemical kinetics model, with self-consistent gas temperature calculation. Specifically, we show that higher energy efficiencies can be reached by correctly tuning the plasma pulse and interpulse times. The ideal plasma pulse time corresponds to the time needed to reach the highest vibrational temperature. In addition, the highest energy efficiencies are obtained with long interpulse times, that is, ≥0.1 s, in which the gas temperature can entirely drop to room temperature. Furthermore, additional cooling of the reactor walls can give higher energy efficiencies at shorter interpulse times of 1 ms. Finally, our model shows that plasma pulsing can significantly improve the energy efficiency at low reduced electric fields (50 and 100 Td, typical for microwave and gliding arc plasmas) and intermediate ionization degrees (5 × 10−7 and 10−6).
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.536
Times cited: 1
DOI: 10.1021/acs.jpcc.9b02362
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“Mechanisms for the trimethylaluminum reaction in aluminum oxide atomic layer deposition on sulfur passivated germanium”. Delabie A, Sioncke S, Rip J, van Elshocht S, Caymax M, Pourtois G, Pierloot K, The journal of physical chemistry: C : nanomaterials and interfaces 115, 17523 (2011). http://doi.org/10.1021/jp206070y
Abstract: Germanium combined with high-κ dielectrics is investigated for the next generations of CMOS devices. Therefore, we study reaction mechanisms for Al2O3 atomic layer deposition on sulfur passivated Ge using calculations based on density functional theory and total reflection X-ray fluorescence (TXRF). TXRF indicates 6 S/nm2 and 4 Al/nm2 after the first TMA/H2O reaction cycle, and growth inhibition from the second reaction cycle on. Calculations are performed on molecular clusters representing −GeSH surface sites. The calculations confirm that the TMA reaction does not affect the S content. On fully SH-terminated Ge, TMA favorably reacts with up to three −GeSH sites, resulting in a near tetrahedral Al coordination. Electron deficient structures with a GeS site shared between two Al atoms are proposed. The impact of the cluster size on the structures and reaction energetics is systematically investigated.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.536
Times cited: 9
DOI: 10.1021/jp206070y
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“Control of surface plasmon localization via self-assembly of silver nanoparticles along silver nanowires”. Tran ML, Centeno SP, Hutchison JA, Engelkamp H, Liang D, Van Tendeloo G, Sels BF, Hofkens J, Uji-i H, Journal of the American Chemical Society 130, 17240 (2008). http://doi.org/10.1021/ja807218e
Abstract: A simple and low-cost method to create metal−metal hybrid nanostructures possessing fairly regularly spaced hot-spots of surface plasmon resonances is proposed. The nanohybrid structure was prepared via self-assembly during a simple drop-casting procedure, using chemically synthesized silver nanowires and silver nanoparticles prepared in a single batch of a polyol process. Wide field illumination of these nanohybrids produced hot-spots with spacings of around 500 nm to 1 ìm. The intensity of the emission/scattering from the hot-spots fluctuates over time. The proposed structure can be useful for the development of molecular-sensors or as a substrate for surface enhanced Raman/fluorescence spectroscopy.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 13.858
Times cited: 51
DOI: 10.1021/ja807218e
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“Changing chirality during single-walled carbon nanotube growth : a reactive molecular dynamics/Monte Carlo study”. Neyts EC, van Duin ACT, Bogaerts A, Journal of the American Chemical Society 133, 17225 (2011). http://doi.org/10.1021/ja204023c
Abstract: The growth mechanism and chirality formation of a single-walled carbon nanotube (SWNT) on a surface-bound nickel nanocluster are investigated by hybrid reactive molecular dynamics/force-biased Monte Carlo simulations. The validity of the interatomic potential used, the so-called ReaxFF potential, for simulating catalytic SWNT growth is demonstrated. The SWNT growth process was found to be in agreement with previous studies and observed to proceed through a number of distinct steps, viz., the dissolution of carbon in the metallic particle, the surface segregation of carbon with the formation of aggregated carbon clusters on the surface, the formation of graphitic islands that grow into SWNT caps, and finally continued growth of the SWNT. Moreover, it is clearly illustrated in the present study that during the growth process, the carbon network is continuously restructured by a metal-mediated process, thereby healing many topological defects. It is also found that a cap can nucleate and disappear again, which was not observed in previous simulations. Encapsulation of the nanoparticle is observed to be prevented by the carbon network migrating as a whole over the cluster surface. Finally, for the first time, the chirality of the growing SWNT cap is observed to change from (11,0) over (9,3) to (7,7). It is demonstrated that this change in chirality is due to the metal-mediated restructuring process.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 13.858
Times cited: 116
DOI: 10.1021/ja204023c
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