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“Sustainability indicators for biobased chemicals : a Delphi study using multi-criteria decision analysis”. Van Schoubroeck S, Springael J, Van Dael M, Malina R, Van Passel S, Resources Conservation And Recycling 144, 198 (2019). http://doi.org/10.1016/J.RESCONREC.2018.12.024
Abstract: Biobased chemistry has gained interest and has the potential to tackle some of the sustainability challenges the chemical industry must endure. Sustainability impacts need to be evaluated and monitored to highlight the advantages and pitfalls of different biobased routes over the entire product life cycle. This study aims for expert consensus concerning indicators needed and preferred for sustainability analysis of biobased chemicals in Europe. Experts are consulted by means of a Delphi method with stakeholders selected from three core groups: the private, public and academic sector. Best-Worst Scaling (BWS) is performed to gather data on the prioritization of the sustainability indicators per respondent. Afterwards, Multi-Criteria Decision Analysis (MCDA) is used to develop a consensus ranking among the experts. The results show that GHG emissions, market potential and acceptance of biobased materials are deemed the most crucial indicators for respectively environmental, economic and social sustainability. Expert consensus is positive in all three sustainability domains, with the strongest consensus measured for environmental sustainability showing a median Kendalls τ of 0.63 (τ ranging from -1 to 1) and the weakest consensus found within social sustainability showing a median Kendalls τ of 0.50. Further research can apply the ranked indicators on specific case studies to evaluate the practicability of the defined indicator set.
Keywords: A1 Journal article; Economics; Engineering sciences. Technology; Engineering Management (ENM)
Impact Factor: 3.313
Times cited: 4
DOI: 10.1016/J.RESCONREC.2018.12.024
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“Theoretical study of scattering in graphene ribbons in the presence of structural and atomistic edge roughness”. Moors K, Contino A, Van de Put ML, Vandenberghe WG, Fischetti M V, Magnus W, Sorée B, Physical review materials 3, 024001 (2019). http://doi.org/10.1103/PHYSREVMATERIALS.3.024001
Abstract: We investigate the diffusive electron-transport properties of charge-doped graphene ribbons and nanoribbons with imperfect edges. We consider different regimes of edge scattering, ranging from wide graphene ribbons with (partially) diffusive edge scattering to ribbons with large width variations and nanoribbons with atomistic edge roughness. For the latter, we introduce an approach based on pseudopotentials, allowing for an atomistic treatment of the band structure and the scattering potential, on the self-consistent solution of the Boltzmann transport equation within the relaxation-time approximation and taking into account the edge-roughness properties and statistics. The resulting resistivity depends strongly on the ribbon orientation, with zigzag (armchair) ribbons showing the smallest (largest) resistivity and intermediate ribbon orientations exhibiting intermediate resistivity values. The results also show clear resistivity peaks, corresponding to peaks in the density of states due to the confinement-induced subband quantization, except for armchair-edge ribbons that show a very strong width dependence because of their claromatic behavior. Furthermore, we identify a strong interplay between the relative position of the two valleys of graphene along the transport direction, the correlation profile of the atomistic edge roughness, and the chiral valley modes, leading to a peculiar strongly suppressed resistivity regime, most pronounced for the zigzag orientation.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Times cited: 4
DOI: 10.1103/PHYSREVMATERIALS.3.024001
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“Transport of cystine across xC-antiporter”. Ghasemitarei M, Yusupov M, Razzokov J, Shokri B, Bogaerts A, Archives of biochemistry and biophysics 664, 117 (2019). http://doi.org/10.1016/j.abb.2019.01.039
Abstract: Extracellular cystine (CYC) uptake by xC antiporter is important for the cell viability. Especially in cancer cells, the upregulation of xC activity is observed, which protects these cells from intracellular oxidative stress. Hence, inhibition of the CYC uptake may eventually lead to cancer cell death. Up to now, the molecular level mechanism of the CYC uptake by xC antiporter has not been studied in detail. In this study, we applied several different simulation techniques to investigate the transport of CYC through xCT, the light subunit of the xC antiporter, which is responsible for the CYC and glutamate translocation. Specifically, we studied the permeation of CYC across three model systems, i.e., outward facing (OF), occluded (OCC) and inward facing (IF) configurations of xCT. We also investigated the effect of mutation of Cys327 to Ala within xCT, which was also studied experimentally in literature. This allowed us to qualitatively compare our computation results with experimental observations, and thus, to validate our simulations. In summary, our simulations provide a molecular level mechanism of the transport of CYC across the xC antiporter, more specifically, which amino acid residues in the xC antiporter play a key role in the uptake, transport and release of CYC.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.165
Times cited: 3
DOI: 10.1016/j.abb.2019.01.039
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“T4,4,4-graphyne : a 2D carbon allotrope with an intrinsic direct bandgap”. Wang W, Li L, Kong X, Van Duppen B, Peeters FM, Solid state communications 293, 23 (2019). http://doi.org/10.1016/J.SSC.2019.02.001
Abstract: A novel two-dimensional (2D) structurally stable carbon allotrope is proposed using first-principles calculations, which is a promising material for water purification and for electronic devices due to its unique porous structure and electronic properties. Rectangular and hexagonal rings are connected with acetylenic linkages, forming a nanoporous structure with a pore size of 6.41 angstrom, which is known as T-4,T-4,T-4-graphyne. This 2D sheet exhibits a direct bandgap of 0.63 eV at the M point, which originates from the p(z)( )atomic orbitals of carbon atoms as confirmed by a tight-binding model. Importantly, T-4,T-4,T-4-graphyne is found to be energetically more preferable than the experimentally realized beta-graphdiyne, it is dynamically stable and can withstand temperatures up to 1500 K.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 1.554
Times cited: 17
DOI: 10.1016/J.SSC.2019.02.001
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“High-TCInterfacial Ferromagnetism in SrMnO3/LaMnO3Superlattices”. Keunecke M, Lyzwa F, Schwarzbach D, Roddatis V, Gauquelin N, Müller-Caspary K, Verbeeck J, Callori SJ, Klose F, Jungbauer M, Moshnyaga V, Advanced functional materials , 1808270 (2019). http://doi.org/10.1002/adfm.201808270
Abstract: Heterostructures of strongly correlated oxides demonstrate various intriguing and potentially useful interfacial phenomena. LaMnO3/SrMnO3 superlattices are presented showcasing a new high‐temperature ferromagnetic phase with Curie temperature, TC ≈360 K, caused by electron transfer from the surface of the LaMnO3 donor layer into the neighboring SrMnO3 acceptor layer. As a result, the SrMnO3 (top)/LaMnO3 (bottom) interface shows an enhancement of the magnetization as depth‐profiled by polarized neutron reflectometry. The length scale of charge transfer, λTF ≈2 unit cells, is obtained from in situ growth monitoring by optical ellipsometry, supported by optical simulations, and further confirmed by high resolution electron microscopy and spectroscopy. A model of the inhomogeneous distribution of electron density in LaMnO3/SrMnO3 layers along the growth direction is concluded to account for a complex interplay between ferromagnetic and antiferromagnetic layers in superlattices.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 15.621
Times cited: 26
DOI: 10.1002/adfm.201808270
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“Quantitative modeling of secondary electron emission from slow-ion bombardment on semiconductors”. Bercx M, Partoens B, Lamoen D, Physical review B 99, 085413 (2019). http://doi.org/10.1103/PhysRevB.99.085413
Abstract: When slow ions incident on a surface are neutralized, the excess potential energy is passed on to an electron inside the surface, leading to emission of secondary electrons. The microscopic description of this process, as
well as the calculation of the secondary electron yield, is a challenging problem due to its complexity as well
as its sensitivity to surface properties. One of the first quantitative descriptions was articulated in the 1950s by
Hagstrum, who based his calculation on a parametrization of the density of states of the material. In this paper, we
present a model for calculating the secondary electron yield, derived from Hagstrum’s initial approach. We use
first-principles density functional theory calculations to acquire the necessary input and introduce the concept of
electron cascades to Hagstrum’s model in order to improve the calculated spectra, as well as remove its reliance
on fitting parameters. We apply our model to He+ and Ne+ ions incident on Ge(111) and Si(111) and obtain
yield spectra that match closely to the experimental results of Hagstrum.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 5
DOI: 10.1103/PhysRevB.99.085413
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“Encapsulation of Noble Metal Nanoparticles through Seeded Emulsion Polymerization as Highly Stable Plasmonic Systems”. Scarabelli L, Schumacher M, Jimenez de Aberasturi D, Merkl J‐P, Henriksen‐Lacey M, Milagres de Oliveira T, Janschel M, Schmidtke C, Bals S, Weller H, Liz‐Marzán LM, Advanced functional materials 29, 1809071 (2019). http://doi.org/10.1002/adfm.201809071
Abstract: The implementation of plasmonic nanoparticles in vivo remains hindered by important limitations such as biocompatibility, solubility in biological fluids, and physiological stability. A general and versatile protocol is presented, based on seeded emulsion polymerization, for the controlled encapsulation of gold and silver nanoparticles. This procedure enables the encapsulation of single nanoparticles as well as nanoparticle clusters inside a protecting polymer shell. Specifically, the efficient coating of nanoparticles of both metals is demonstrated, with final dimensions ranging between 50 and 200 nm, i.e., sizes of interest for bio-applications. Such hybrid nanocomposites display extraordinary stability in high ionic strength and oxidizing environments, along with high cellular uptake, and low cytotoxicity. Overall, the prepared nanostructures are promising candidates for plasmonic applications under biologically relevant conditions.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 12.124
Times cited: 19
DOI: 10.1002/adfm.201809071
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“Bio-based aromatic amines from lignin-derived monomers”. Blondiaux E, Bomon J, Smolen M, Kaval N, Lemière F, Sergeyev S, Diels L, Sels B, Maes BUW, ACS Sustainable Chemistry and Engineering 7, 6906 (2019). http://doi.org/10.1021/ACSSUSCHEMENG.8B06467
Abstract: A new approach to synthesize valuable 3,4-dialkoxyanilines and alkyl propionates from lignin-derived 4-propylguaiacol and -catechol with overall isolated yields up to 65% has been described. The strategy is based on the introduction of nitrogen via a Beckmann rearrangement. Amino introduction therefore coincides with a C-defunctionalization reaction; overall a replacement of the propyl chain by an amino group is obtained. The process only requires cheap bulk chemicals as reagents/reactants and does not involve column chromatography to purify the reaction products. Furthermore, all carbon atoms from the biorenewable lignin-derived monomers are transformed into valuable compounds. Greenness was assessed by performing a Green Metrics analysis on two dialkoxyanilines. A comparison was made with literature routes for these compounds starting from a petrochemical substrate.
Keywords: A1 Journal article; Engineering sciences. Technology; Organic synthesis (ORSY); Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1021/ACSSUSCHEMENG.8B06467
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“Single-site metal-organic framework catalysts for the oxidative coupling of arenes via C-H/C-H activation”. Van Velthoven N, Waitschat S, Chavan SM, Liu P, Smolders S, Vercammen J, Bueken B, Bals S, Lillerud KP, Stock N, De Vos DE, Chemical science 10, 3616 (2019). http://doi.org/10.1039/C8SC05510F
Abstract: C-H activation reactions are generally associated with relatively low turnover numbers (TONs) and high catalyst concentrations due to a combination of low catalyst stability and activity, highlighting the need for recyclable heterogeneous catalysts with stable single-atom active sites. In this work, several palladium loaded metal-organic frameworks (MOFs) were tested as single-site catalysts for the oxidative coupling of arenes (e.g. o-xylene) via C-H/C-H activation. Isolation of the palladium active sites on the MOF supports reduced Pd(0) aggregate formation and thus catalyst deactivation, resulting in higher turnover numbers (TONs) compared to the homogeneous benchmark reaction. Notably, a threefold higher TON could be achieved for palladium loaded MOF-808 due to increased catalyst stability and the heterogeneous catalyst could efficiently be reused, resulting in a cumulative TON of 1218 after three runs. Additionally, the palladium single-atom active sites on MOF-808 were successfully identified by Fourier transform infrared (FTIR) and extended X-ray absorption fine structure (EXAFS) spectroscopy.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 8.668
Times cited: 68
DOI: 10.1039/C8SC05510F
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“Tetragonal Cs1.17In0.81Cl3 : a charge-ordered indium halide perovskite derivative”. Tan X, Stephens PW, Hendrickx M, Hadermann J, Segre CU, Croft M, Kang C-J, Deng Z, Lapidus SH, Kim SW, Jin C, Kotliar G, Greenblatt M, Chemistry of materials 31, 1981 (2019). http://doi.org/10.1021/ACS.CHEMMATER.8B04771
Abstract: Polycrystalline samples of Cs1.17In0.81Cl3 were prepared by annealing a mixture of CsCl, InCl, and InCl3, stoichiometric for the targeted CsInCl3. Synchrotron powder X-ray diffraction refinement and chemical analysis by energy dispersive X-ray indicated that Cs1.17In0.81Cl3, a tetragonal distorted perovskite derivative (I4/m), is the thermodynamically stable product. The refined unit cell parameters and space group were confirmed by electron diffraction. In the tetragonal structure, In+ and In3+ are located in four different crystallographic sites, consistent with their corresponding bond lengths. In1, In2, and In3 are octahedrally coordinated, whereas In4 is at the center of a pentagonal bipyramid of Cl because of the noncooperative octahedral tilting of In4Cl6. The charged-ordered In+ and In3+ were also confirmed by X-ray absorption and Raman spectroscopy. Cs1.17In0.81Cl3 is the first example of an inorganic halide double perovskite derivative with charged-ordered In+ and In3+. Band structure and optical conductivity calculations were carried out with both generalized gradient approximation (GGA) and modified Becke-Johnson (mBJ) approach; the GGA calculations estimated the band gap and optical band gap to be 2.27 eV and 2.4 eV, respectively. The large and indirect band gap suggests that Cs1.17In0.81Cl3 is not a good candidate for photovoltaic application.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 9.466
Times cited: 6
DOI: 10.1021/ACS.CHEMMATER.8B04771
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“Suppressing the formation of NOxand N2O in CO2/N2dielectric barrier discharge plasma by adding CH4: scavenger chemistry at work”. Snoeckx R, Van Wesenbeeck K, Lenaerts S, Cha MS, Bogaerts A, Sustainable Energy &, Fuels 3, 1388 (2019). http://doi.org/10.1039/C8SE00584B
Abstract: The need for carbon negative technologies led to the development of a wide array of novel CO<sub>2</sub>conversion techniques. Most of them either rely on high temperatures or generate highly reactive O species, which can lead to the undesirable formation of NO<sub>x</sub>and N<sub>2</sub>O when the CO<sub>2</sub>feeds contain N<sub>2</sub>. Here, we show that, for plasma-based CO<sub>2</sub>conversion, adding a hydrogen source, as a chemical oxygen scavenger, can suppress their formation,<italic>in situ</italic>. This allows the use of low-cost N<sub>2</sub>containing (industrial and direct air capture) feeds, rather than expensive purified CO<sub>2</sub>. To demonstrate this, we add CH<sub>4</sub>to a dielectric barrier discharge plasma used for converting impure CO<sub>2</sub>. We find that when adding a stoichiometric amount of CH<sub>4</sub>, 82% less NO<sub>2</sub>and 51% less NO are formed. An even higher reduction (96 and 63%) can be obtained when doubling this amount. However, in that case the excess radicals promote the formation of by-products, such as HCN, NH<sub>3</sub>and CH<sub>3</sub>OH. Thus, we believe that by using an appropriate amount of chemical scavengers, we can use impure CO<sub>2</sub>feeds, which would bring us closer to ‘real world’ conditions and implementation.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT); Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1039/C8SE00584B
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“Proportional relationship between leaf area and the product of leaf length and width of four types of special leaf shapes”. Shi P, Liu M, Yu X, Gielis J, Ratkowsky DA, Forests (19994907) 10, 178 (2019). http://doi.org/10.3390/F10020178
Abstract: The leaf area, as an important leaf functional trait, is thought to be related to leaf length and width. Our recent study showed that the Montgomery equation, which assumes that leaf area is proportional to the product of leaf length and width, applied to different leaf shapes, and the coefficient of proportionality (namely the Montgomery parameter) range from 1/2 to π/4. However, no relevant geometrical evidence has previously been provided to support the above findings. Here, four types of representative leaf shapes (the elliptical, sectorial, linear, and triangular shapes) were studied. We derived the range of the estimate of the Montgomery parameter for every type. For the elliptical and triangular leaf shapes, the estimates are π/4 and 1/2, respectively; for the linear leaf shape, especially for the plants of Poaceae that can be described by the simplified Gielis equation, the estimate ranges from 0.6795 to π/4; for the sectorial leaf shape, the estimate ranges from 1/2 to π/4. The estimates based on the observations of actual leaves support the above theoretical results. The results obtained here show that the coefficient of proportionality of leaf area versus the product of leaf length and width only varies in a small range, maintaining the allometric relationship for leaf area and thereby suggesting that the proportional relationship between leaf area and the product of leaf length and width broadly remains stable during leaf evolution.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.3390/F10020178
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“First-Principles Investigation of the Stability of the Oxygen Framework of Li-Rich Battery Cathodes”. Bercx M, Slap L, Partoens B, Lamoen D, MRS advances 4, 813 (2019). http://doi.org/10.1557/adv.2019.135
Abstract: Lithium-rich layered oxides such as Li<sub>2</sub>MnO<sub>3</sub>have shown great potential as cathodes in Li-ion batteries, mainly because of their large capacities. However, these materials still suffer from structural degradation as the battery is cycled, reducing the average voltage and capacity of the cell. The voltage fade is believed to be related to the migration of transition metals into the lithium layer, linked to the formation of O-O dimers with a short bond length, which in turn is driven by the presence of oxygen holes due to the participation of oxygen in the redox process. We investigate the formation of O-O dimers for partially charged O1-Li<sub>2</sub>MnO<sub>3</sub>using a first-principles density functional theory approach by calculating the reaction energy and kinetic barriers for dimer formation. Next, we perform similar calculations for partially charged O1-Li<sub>2</sub>IrO<sub>3</sub>, a Li-rich material for which the voltage fade was not observed during cycling. When we compare the stability of the oxygen framework, we conclude that the formation of O-O dimers is both thermodynamically and kinetically viable for O1-Li<sub>0.5</sub>MnO<sub>3</sub>. For O1-Li<sub>0.5</sub>IrO<sub>3</sub>, we observe that the oxygen lattice is much more stable, either returning to its original state when perturbed, or resulting in a structure with an O-O dimer that is much higher in energy. This can be explained by the mixed redox process for Li<sub>2</sub>IrO<sub>3</sub>, which is also shown from the calculated magnetic moments. The lack of O-O dimer formation in O1-Li<sub>0.5</sub>IrO<sub>3</sub>provides valuable insight as to why Li<sub>2</sub>IrO<sub>3</sub>does not demonstrate a voltage fade as the battery is cycled, which can be used to design Li-rich battery cathodes with an improved cycling performance.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
Times cited: 3
DOI: 10.1557/adv.2019.135
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“Experimental observation of electron-phonon coupling enhancement in Sn nanowires caused by phonon confinement effects”. Lozano DP, Couet S, Petermann C, Hamoir G, Jochum JK, Picot T, Menendez E, Houben K, Joly V, Antohe VA, Hu MY, Leu BM, Alatas A, Said AH, Roelants S, Partoens B, Milošević, MV, Peeters FM, Piraux L, Van de Vondel J, Vantomme A, Temst K, Van Bael MJ, Physical review B 99, 064512 (2019). http://doi.org/10.1103/PHYSREVB.99.064512
Abstract: Reducing the size of a superconductor below its characteristic length scales can either enhance or suppress its critical temperature (T-c). Depending on the bulk value of the electron-phonon coupling strength, electronic and phonon confinement effects will play different roles in the modification of T-c. Experimentally disentangling each contribution has remained a challenge. We have measured both the phonon density of states and T-c of Sn nanowires with diameters of 18, 35, and 100 nm in order to quantify the effects of phonon confinement on superconductivity. We observe a shift of the phonon frequency towards the low-energy region and an increase in the electron-phonon coupling constant that can account for the measured increase in T-c.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 11
DOI: 10.1103/PHYSREVB.99.064512
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“CO2 activation on TiO2-supported Cu5 and Ni5 nanoclusters : effect of plasma-induced surface charging”. Jafarzadeh A, Bal KM, Bogaerts A, Neyts EC, The journal of physical chemistry: C : nanomaterials and interfaces 123, 6516 (2019). http://doi.org/10.1021/ACS.JPCC.8B11816
Abstract: Surface charging is an often overlooked factor in many plasma-surface interactions and in particular in plasma catalysis. In this study, we investigate the effect of excess electrons induced by a plasma on the adsorption properties of CO2 on titania-supported Cu-5 and Ni-5 clusters using spin-polarized and dispersion-corrected density functional theory calculations. The effect of excess electrons on the adsorption of Ni and Cu pentamers as well as on CO2 adsorption on a pristine anatase TiO2(101) slab is studied. Our results indicate that adding plasma-induced excess electrons to the system leads to further stabilization of the bent CO2 structure. Also, dissociation of CO2 on charged clusters is energetically more favorable than on neutral clusters. We hypothesize that surface charge is a plausible cause for the synergistic effects sometimes observed in plasma catalysis.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.536
Times cited: 4
DOI: 10.1021/ACS.JPCC.8B11816
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“Image analysis and in situ FTIR as complementary detection tools for photocatalytic soot oxidation”. Van Hal M, Verbruggen SW, Yang X-Y, Lenaerts S, Tytgat T, Chemical engineering journal 367, 269 (2019). http://doi.org/10.1016/J.CEJ.2019.02.154
Abstract: Air pollution, especially particulate matter (PM), is an increasingly urgent problem in urban environments, causing both short and long-term health problems, climate interference and aesthetical problems due to building fouling. Photocatalysis has been shown to be a possible solution to that end. In this work two complementary detection methods for photocatalytic soot oxidation are studied and their advantages and disadvantages are discussed. First, a colour-based digital image analysis method is drastically improved towards an accurate, detailed and straightforward detection tool, that enables simultaneous measurement of the degradation of different grades of soot fouling (for instance a shallow soot haze versus condensed soot deposits). In the next part, a second soot oxidation detection method is presented based on in situ FTIR spectroscopy. This method has the additional advantage of providing more insight into the photocatalytic soot degradation process by monitoring both gaseous and adsorbed intermediates as well as reaction products while the reactions are ongoing. As an illustration, the proposed detection strategies were applied on four different commercially available and synthesized photocatalytic materials. The digital image analysis showed that P25 (Evonik) is the fastest photocatalytic soot degrader of all studied materials for both a uniform soot haze as well as concentrated soot spots. Application of the in situ method showed that for all studied materials adsorbed formate-related surface species were formed and that commercially available ZnO nanopowder has the highest specificity towards complete mineralization into CO2. With this we aim to provide a set of complementary experimental tools for the convenient, reliable, realistic and standardised detection of photocatalytic soot degradation.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 6.216
Times cited: 1
DOI: 10.1016/J.CEJ.2019.02.154
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“Layered CeSO and LiCeSO oxide chalcogenides obtained via topotactic oxidative and reductive transformations”. Cassidy SJ, Pitcher MJ, Lim JJK, Hadermann J, Allen JP, Watson GW, Britto S, Chong EJ, Free DG, Grey CP, Clarke SJ, Inorganic chemistry 58, 3838 (2019). http://doi.org/10.1021/ACS.INORGCHEM.8B03485
Abstract: The chemical accessibility of the Celv oxidation state enables redox chemistry to be performed on the naturally coinagemetal -deficient phases CeM1-xSO (M = Cu, Ag). A metastable black compound with the PbFC1 structure type (space group P4/nmm: a = 3.8396(1) angstrom, c = 6.607(4) angstrom, V = 97.40(6) angstrom(3)) and a composition approaching CeSO is obtained by deintercalation of Ag from CeAg0.8SO. High-resolution transmission electron microscopy reveals the presence of large defect-free regions in CeSO, but stacking faults are also evident which can be incorporated into a quantitative model to account for the severe peak anisotropy evident in all the highresolution X-ray and neutron diffractograms of bulk CeSO samples; these suggest that a few percent of residual Ag remains. A strawcolored compound with the filled PbFCI (i.e., ZrSiCuAs- or HfCuSi2type) structure (space group P4/nmm: a = 3.98171(1) angstrom, c = 8.70913(5) angstrom, V = 138.075(1) angstrom 3) and a composition close to LiCeSO, but with small amounts of residual Ag, is obtained by direct reductive lithiation of CeAga8S0 or by insertion of Li into CeSO using chemical or electrochemical means. Computation of the band structure of pure, stoichiometric CeSO predicts it to be a Ce' compound with the 4f-states lying approximately 1 eV above the sulfide-dominated valence band maximum. Accordingly, the effective magnetic moment per Ce ion measured in the CeSO samples is much reduced from the value found for the Ce3+-containing LiCeSO, and the residual paramagnetism corresponds to the Ce3+ ions remaining due to the presence of residual Ag, which presumably reflects the difficulty of stabilizing Ce' in the presence of sulfide (S2-). Comparison of the behavior of CeCu0.8SO with that of CeCu0.8SO reveals much slower reaction kinetics associated with the Cu,_xS layers, and this enables intermediate CeCui LixSO phases to be isolated.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.857
DOI: 10.1021/ACS.INORGCHEM.8B03485
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“Magnetic properties of La3Ni2Sb Ta Nb1––O9, from relaxor to spin glass”. Chin C–M, Battle PD, Hunter EC, Avdeev M, Hendrickx M, Hadermann J, Journal of solid state chemistry (Print) 273, 175 (2019). http://doi.org/10.1016/j.jssc.2019.02.044
Abstract: Neutron diffraction experiments conducted at 5 K in a magnetic field 0 < H/kOe < 50 have shown that the monoclinic perovskite La3Ni2TaO9 behaves as a relaxor ferromagnet. Compositions in the series La3Ni2SbxTayNb1–x–yO9 have been synthesized in polycrystalline form. Electron microscopy, X–ray diffraction and neutron diffraction have shown that the solid solutions are largely homogeneous and monophasic. Magnetometry and neutron diffraction have shown that the relaxor magnetisation persists in low fields when x + y = 1 but is rapidly diminished by the introduction of niobium. This change in magnetic behaviour is ascribed to the differences in the d–orbital energies of Sb5+, Nb5+ and Ta5+.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
DOI: 10.1016/j.jssc.2019.02.044
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“In vitro and ex vivo assessment of microporous Faujasite zeolite (NaX-FAU) as a carrier for the oral delivery of danazol”. Kontogiannidou E, Karavasili C, Kouskoura MG, Filippousi M, Van Tendeloo G, Andreadis II, Eleftheriadis GK, Kontopoulou I, Markopoulou CK, Bouropoulos N, Fatouros DG, Journal of drug delivery science and technology 51, 177 (2019). http://doi.org/10.1016/J.JDDST.2019.02.036
Abstract: Microporous zeolite NaX-FAU has been systemically evaluated for the oral delivery of the poorly water-soluble compound danazol. For this purpose, danazol-loaded zeolitic particles were prepared by the incipient wetness method and were characterized by means of N-2 physisorption, X-ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and high-resolution transmission electron microscopy (HRTEM). The zeolitic formulation shows a high drug payload and drug stability over a period of six months under accelerated storage conditions. The dissolution profile of danazol-loaded zeolitic particles was assessed in simulated gastric fluid (SGF) pH 1.2; fasted state simulated intestinal fluids (FaSSIF) and fed state simulated intestinal fluid (FeSSIF) showing a gradual and increasing drug dissolution in the different media. Ex vivo studies using the everted gut sac model show an increased drug transport across rat intestinal epithelium when loaded in the zeolitic particles. Our results suggest that microporous Faujasite zeolite (NaX-FAU) could be used as a drug delivery system to facilitate the oral delivery of poorly water soluble compounds.
Keywords: A1 Journal article; Pharmacology. Therapy; Electron microscopy for materials research (EMAT)
Impact Factor: 1.194
Times cited: 3
DOI: 10.1016/J.JDDST.2019.02.036
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“Tunable 2D-gallium arsenide and graphene bandgaps in a graphene/GaAs heterostructure : an ab initio study”. Gonzalez-Garcia A, Lopez-Perez W, Gonzalez-Hernandez R, Rodriguez JA, Milošević, MV, Peeters FM, Journal of physics : condensed matter 31, 265502 (2019). http://doi.org/10.1088/1361-648X/AB0D70
Abstract: The bandgap behavior of 2D-GaAs and graphene have been investigated with van der Waals heterostructured into a yet unexplored graphene/GaAs bilayer, under both uniaxial stress along c axis and different planar strain distributions. The 2D-GaAs bandgap nature changes from Gamma-K indirect in isolated monolayer to Gamma-Gamma direct in graphene/GaAs bilayer. In the latter, graphene exhibits a bandgap of 5 meV. The uniaxial stress strongly affects the graphene electronic bandgap, while symmetric in-plane strain does not open the bandgap in graphene. Nevertheless, it induces remarkable changes on the GaAs bandgap-width around the Fermi level. However, when applying asymmetric in-plane strain to graphene/GaAs, the graphene sublattice symmetry is broken, and the graphene bandgap is open at the Fermi level to a maximum width of 814 meV. This value is much higher than that reported for just graphene under asymmetric strain. The Gamma-Gamma direct bandgap of GaAs remains unchanged in graphene/ GaAs under different types of applied strain. The analyses of phonon dispersion and the elastic constants yield the dynamical and mechanical stability of the graphene/GaAs system, respectively. The calculated mechanical properties for bilayer heterostructure are better than those of their constituent monolayers. This finding, together with the tunable graphene bandgap not only by the strength but also by the direction of the strain, enhance the potential for strain engineering of ultrathin group-III-V electronic devices hybridized by graphene.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.649
Times cited: 10
DOI: 10.1088/1361-648X/AB0D70
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“Deflection of ferromagnetic and antiferromagnetic skyrmions at heterochiral interfaces”. Menezes RM, Mulkers J, de Souza Silva CC, Milošević, MV, Physical review B 99, 104409 (2019). http://doi.org/10.1103/PHYSREVB.99.104409
Abstract: Devising magnetic nanostructures with spatially heterogeneous Dzyaloshinskii-Moriya interaction (DMI) is a promising pathway toward advanced confinement and control of magnetic skyrmions in potential devices. Here we discuss theoretically how a skyrmion interacts with a heterochiral interface using micromagnetic simulations and analytic arguments. We show that a heterochiral interface deflects the trajectory of ferromagnetic (FM) skyrmions, and that the extent of such deflection is tuned by the applied spin-polarized current and the difference in DMI across the interface. Further, we show that this deflection is characteristic of the FM skyrmion, and it is completely absent in the antiferromagnetic (AFM) case. In turn, we reveal that the AFM skyrmion achieves much higher velocities than its FM counterpart, yet experiences far stronger confinement in nanoengineered heterochiral tracks, which reinforces AFM skyrmions as a favorable choice for skyrmion-based devices.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 19
DOI: 10.1103/PHYSREVB.99.104409
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“Electrical Polarization in AlN/GaN Nanodisks Measured by Momentum-Resolved 4D Scanning Transmission Electron Microscopy”. Müller-Caspary K, Grieb T, Müßener J, Gauquelin N, Hille P, Schörmann J, Verbeeck J, Van Aert S, Eickhoff M, Rosenauer A, Physical review letters 122, 106102 (2019). http://doi.org/10.1103/PhysRevLett.122.106102
Abstract: We report the mapping of polarization-induced internal electric fields in AlN/GaN nanowire heterostructures at unit cell resolution as a key for the correlation of optical and structural phenomena in semiconductor optoelectronics. Momentum-resolved aberration-corrected scanning transmission electron microscopy is employed as a new imaging mode that simultaneously provides four-dimensional data in real and reciprocal space. We demonstrate how internal mesoscale and atomic electric fields can be separated in an experiment, which is verified by comprehensive dynamical simulations of multiple electron scattering. A mean difference of 5.3 +- 1.5 MV/cm is found for the polarization-induced electric fields in AlN and GaN, being in accordance with dedicated simulations and photoluminescence measurements in previous publications.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 8.462
Times cited: 26
DOI: 10.1103/PhysRevLett.122.106102
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“A Facet-Specific Quantum Dot Passivation Strategy for Colloid Management and Efficient Infrared Photovoltaics”. Kim Y, Che F, Jo JW, Choi J, de Arquer FPG, Voznyy O, Sun B, Kim J, Choi M-J, Quintero-Bermudez R, Fan F, Tan CS, Bladt E, Walters G, Proppe AH, Zou C, Yuan H, Bals S, Hofkens J, Roeffaers MBJ, Hoogland S, Sargent EH, Advanced materials 31, 1805580 (2019). http://doi.org/10.1002/ADMA.201805580
Abstract: Colloidal nanocrystals combine size- and facet-dependent properties with solution processing. They offer thus a compelling suite of materials for technological applications. Their size- and facet-tunable features are studied in synthesis; however, to exploit their features in optoelectronic devices, it will be essential to translate control over size and facets from the colloid all the way to the film. Larger-diameter colloidal quantum dots (CQDs) offer the attractive possibility of harvesting infrared (IR) solar energy beyond absorption of silicon photovoltaics. These CQDs exhibit facets (nonpolar (100)) undisplayed in small-diameter CQDs; and the materials chemistry of smaller nanocrystals fails consequently to translate to materials for the short-wavelength IR regime. A new colloidal management strategy targeting the passivation of both (100) and (111) facets is demonstrated using distinct choices of cations and anions. The approach leads to narrow-bandgap CQDs with impressive colloidal stability and photoluminescence quantum yield. Photophysical studies confirm a reduction both in Stokes shift (approximate to 47 meV) and Urbach tail (approximate to 29 meV). This approach provides a approximate to 50% increase in the power conversion efficiency of IR photovoltaics compared to controls, and a approximate to 70% external quantum efficiency at their excitonic peak.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 19.791
Times cited: 74
DOI: 10.1002/ADMA.201805580
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“Overcoming Old Scaling Relations and Establishing New Correlations in Catalytic Surface Chemistry: Combined Effect of Charging and Doping”. Bal KM, Neyts EC, The journal of physical chemistry: C : nanomaterials and interfaces 123, 6141 (2019). http://doi.org/10.1021/acs.jpcc.9b01216
Abstract: Optimization of catalytic materials for a given application is greatly constrained by linear scaling relations. Recently, however, it has been demonstrated that it is possible to reversibly modulate the chemisorption of molecules on nanomaterials by charging (i.e., injection or removal of electrons) and hence reversibly and selectively modify catalytic activity beyond structure−activity correlations. The fundamental physical relation between the properties of the material, the charging process, and the chemisorption energy, however, remains unclear, and a systematic exploration and optimization of charge-switchable sorbent materials is not yet possible. Using hybrid DFT calculations of CO2 chemisorption on hexagonal boron nitride nanosheets with several types of defects and dopants, we here reveal the existence of fundamental correlations between the electron affinity of a material and charge-induced chemisorption, show how defect engineering can be used to modulate the strength and efficiency of the adsorption process, and demonstrate that excess electrons stabilize many topological defects. We then show how these insights could be exploited in the development of new electrocatalytic materials and the synthesis of doped nanomaterials. Moreover, we demonstrate that calculated chemical properties of charged materials are highly sensitive to the employed computational methodology because of the self-interaction error, which underlines the theoretical challenge posed by such systems.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.536
Times cited: 5
DOI: 10.1021/acs.jpcc.9b01216
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“The effect of policy leveraging climate change adaptive capacity in agriculture”. Vanschoenwinkel J, Moretti M, Van Passel S, European Review Of Agricultural Economics (2020). http://doi.org/10.1093/erae/jbz007
Abstract: Agricultural adaptation to climate change is indispensable. However, the degree of adaptation depends on adaptive capacity levels and it only takes place if the appropriate resources are present. Cross-sectional climate response models ignore this requirement. This paper adapts the Ricardian method to control for a generic territorial adaptive capacity index. The results for a sample of over 60.000 European farms show a significant non-linear positive relationship between adaptive capacity and climate responsiveness and that some regions in Europe can increase their climate responsiveness significantly. This confirms that improvement of adaptive capacity is an important policy tool to enhance adaptation.
Keywords: A1 Journal Article; Engineering Management (ENM)
Impact Factor: 3.4
DOI: 10.1093/erae/jbz007
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“Determining stoichiometry and kinetics of two thermophilic nitrifying communities as a crucial step in the development of thermophilic nitrogen removal”. Vanderkerckhove TGL, Kerckhof F-M, De Mulder C, Vlaeminck SE, Boon N, Water research 156, 34 (2019). http://doi.org/10.1016/J.WATRES.2019.03.008
Abstract: Nitrification and denitrification, the key biological processes for thermophilic nitrogen removal, have separately been established in bioreactors at 50 °C. A well-characterized set of kinetic parameters is essential to integrate these processes while safeguarding the autotrophs performing nitrification. Knowledge on thermophilic nitrifying kinetics is restricted to isolated or highly enriched batch cultures, which do not represent bioreactor conditions. This study characterized the stoichiometry and kinetics of two thermophilic (50 °C) nitrifying communities. The most abundant ammonia oxidizing archaea (AOA) were related to the Nitrososphaera genus, clustering relatively far from known species Nitrososphaera gargensis (95.5% 16S rRNA gene sequence identity). The most abundant nitrite oxidizing bacteria (NOB) were related to Nitrospira calida (97% 16S rRNA gene sequence identity). The nitrification biomass yield was 0.200.24 g VSS g−1 N, resulting mainly from a high AOA yield (0.160.20 g VSS g−1 N), which was reflected in a high AOA abundance in the community (5776%) compared to NOB (511%). Batch-wise determination of decay rates (AOA: 0.230.29 d−1; NOB: 0.320.43 d−1) rendered an overestimation compared to in situ estimations of overall decay rate (0.0260.078 d−1). Possibly, the inactivation rate rather than the actual decay rate was determined in batch experiments. Maximum growth rates of AOA and NOB were 0.120.15 d−1 and 0.130.33 d−1 respectively. NOB were susceptible to nitrite, opening up opportunities for shortcut nitrogen removal. However, NOB had a similar growth rate and oxygen affinity (0.150.55 mg O2 L−1) as AOA and were resilient towards free ammonia (IC50 > 16 mg NH3-N L−1). This might complicate NOB outselection using common practices to establish shortcut nitrogen removal (SRT control; aeration control; free ammonia shocks). Overall, the obtained insights can assist in integrating thermophilic conversions and facilitate single-sludge nitrification/denitrification.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1016/J.WATRES.2019.03.008
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“Conductance fluctuations of monolayer GeSnH2$ in the topological phase using a low-energy effective tight-binding Hamiltonian”. Aslani Z, Sisakht ET, Fazileh F, Ghorbanfekr-Kalashami H, Peeters FM, Physical review B 99, 115421 (2019). http://doi.org/10.1103/PHYSREVB.99.115421
Abstract: An effective tight-binding (TB) Hamiltonian for monolayer GeSnH2 is constructed which has an inversion-asymmetric honeycomb structure. The low-energy band structure of our TB model agrees very well with previous ab initio calculations even under biaxial tensile strain. Our model predicts a phase transition at 7.5% biaxial tensile strain in agreement with DFT calculations. Upon 8.5% strain the system exhibits a band gap of 134 meV, suitable for room temperature applications. It is shown that an external applied magnetic field produces a special phase which is a combination of the quantum Hall (QH) and quantum spin Hall (QSH) phases; and at a critical magnetic field strength the QSH phase completely disappears. The topological nature of the phase transition is confirmed from: (1) the calculation of the Z(2) topological invariant, and (2) quantum transport properties of disordered GeSnH2 nanoribbons which allows us to determine the universality class of the conductance fluctuations. The application of an external applied magnetic field reduces the conductance fluctuations by a factor of root 2.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 3
DOI: 10.1103/PHYSREVB.99.115421
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“Effect of zinc oxide modification by indium oxide on microstructure, adsorbed surface species, and sensitivity to CO”. Marikutsa A, Rumyantseva M, Gaskov A, Batuk M, Hadermann J, Sarmadian N, Saniz R, Partoens B, Lamoen D, Frontiers in materials 6 (2019). http://doi.org/10.3389/FMATS.2019.00043
Abstract: Additives in semiconductor metal oxides are commonly used to improve sensing behavior of gas sensors. Due to complicated effects of additives on the materials microstructure, adsorption sites and reactivity to target gases the sensing mechanism with modified metal oxides is a matter of thorough research. Herein, we establish the promoting effect of nanocrystalline zinc oxide modification by 1-7 at.% of indium on the sensitivity to CO gas due to improved nanostructure dispersion and concentration of active sites. The sensing materials were synthesized via an aqueous coprecipitation route. Materials composition, particle size and BET area were evaluated using X-ray diffraction, nitrogen adsorption isotherms, high-resolution electron microscopy techniques and EDX-mapping. Surface species of chemisorbed oxygen, OH-groups, and acid sites were characterized by probe molecule techniques and infrared spectroscopy. It was found that particle size of zinc oxide decreased and the BET area increased with the amount of indium oxide. The additive was observed as amorphous indium oxide segregated on agglomerated ZnO nanocrystals. The measured concentration of surface species was higher on In2O3-modified zinc oxide. With the increase of indium oxide content, the sensor response of ZnO/In2O3 to CO was improved. Using in situ infrared spectroscopy, it was shown that oxidation of CO molecules was enhanced on the modified zinc oxide surface. The effect of modifier was attributed to promotion of surface OH-groups and enhancement of CO oxidation on the segregated indium ions, as suggested by DFT in previous work.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
Times cited: 11
DOI: 10.3389/FMATS.2019.00043
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“Hydrogenation of Carbon Dioxide to Value-Added Chemicals by Heterogeneous Catalysis and Plasma Catalysis”. Liu M, Yi Y, Wang L, Guo H, Bogaerts A, Catalysts 9, 275 (2019). http://doi.org/10.3390/catal9030275
Abstract: Due to the increasing emission of carbon dioxide (CO2), greenhouse effects are becoming more and more severe, causing global climate change. The conversion and utilization of CO2 is one of the possible solutions to reduce CO2 concentrations. This can be accomplished, among other methods, by direct hydrogenation of CO2, producing value-added products. In this review, the progress of mainly the last five years in direct hydrogenation of CO2 to value-added chemicals (e.g., CO, CH4, CH3OH, DME, olefins, and higher hydrocarbons) by heterogeneous catalysis and plasma catalysis is summarized, and research priorities for CO2 hydrogenation are proposed.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.082
DOI: 10.3390/catal9030275
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“Electric-field-induced emergent electrical connectivity in graphene oxide”. Neek-Amal M, Rashidi R, Nair RR, Neilson D, Peeters FM, Physical review B 99, 115425 (2019). http://doi.org/10.1103/PHYSREVB.99.115425
Abstract: Understanding the appearance of local electrical connectivity in liquid filled layered graphene oxide subjected to an external electric field is important to design electrically controlled smart permeable devices and also to gain insight into the physics behind electrical effects on confined water permeation. Motivated by recent experiments [K. G. Zhou et al. Nature (London) 559, 236 (2018)], we introduce a new model with random percolating paths for electrical connectivity in micron thick water filled layered graphene oxide, which mimics parallel resistors connected across the top and bottom electrodes. We find that a strong nonuniform radial electric field of the order similar to 10-50 mV/nm can be induced between layers depending on the current flow through the formed conducting paths. The maxima of the induced fields are not necessarily close to the electrodes and may be localized in the middle region of the layered material. The emergence of electrical connectivity and the associated electrical effects have a strong influence on the surrounding fluid in terms of ionization and wetting which subsequently determines the permeation properties.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 3
DOI: 10.1103/PHYSREVB.99.115425
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