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Author Fatermans, J.; den Dekker, Aj.; Müller-Caspary, K.; Gauquelin, N.; Verbeeck, J.; Van Aert, S.
Title Atom column detection from simultaneously acquired ABF and ADF STEM images Type A1 Journal article
Year (down) 2020 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 219 Issue Pages 113046
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract In electron microscopy, the maximum a posteriori (MAP) probability rule has been introduced as a tool to determine the most probable atomic structure from high-resolution annular dark-field (ADF) scanning transmission electron microscopy (STEM) images exhibiting low contrast-to-noise ratio (CNR). Besides ADF imaging, STEM can also be applied in the annular bright-field (ABF) regime. The ABF STEM mode allows to directly visualize light-element atomic columns in the presence of heavy columns. Typically, light-element nanomaterials are sensitive to the electron beam, limiting the incoming electron dose in order to avoid beam damage and leading to images exhibiting low CNR. Therefore, it is of interest to apply the MAP probability rule not only to ADF STEM images, but to ABF STEM images as well. In this work, the methodology of the MAP rule, which combines statistical parameter estimation theory and model-order selection, is extended to be applied to simultaneously acquired ABF and ADF STEM images. For this, an extension of the commonly used parametric models in STEM is proposed. Hereby, the effect of specimen tilt has been taken into account, since small tilts from the crystal zone axis affect, especially, ABF STEM intensities. Using simulations as well as experimental data, it is shown that the proposed methodology can be successfully used to detect light elements in the presence of heavy elements.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000594768500005 Publication Date 2020-06-01
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0304-3991 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.2 Times cited 9 Open Access OpenAccess
Notes The authors acknowledge financial support from the Research Foundation Flanders (FWO, Belgium) through project fundings (No. W.O.010.16N, No. G.0368.15N, No. G.0502.18N, EOS 30489208). This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (Grant Agreement No. 770887). The authors acknowledge funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 823717 – ESTEEM3. The direct electron detector (Medipix3, Quantum Detectors) was funded by the Hercules fund from the Flemish Government. K. M. C. acknowledges funding from the Initiative and Network Fund of the Helmholtz Association (Germany) under contract VH-NG-1317. The authors thank Mark Huijben from the University of Twente (Enschede, The Netherlands) for providing the LiMn2O4 sample used in section 4.2 of this study. N. G., J. V., and S. V. A. acknowledge funding from the University of Antwerp through the Concerted Research Actions (GOA) project Solarpaint and the TOP project. Approved Most recent IF: 2.2; 2020 IF: 2.843
Call Number EMAT @ emat @c:irua:169706 Serial 6373
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Author Prabhakara, V.; Jannis, D.; Guzzinati, G.; Béché, A.; Bender, H.; Verbeeck, J.
Title HAADF-STEM block-scanning strategy for local measurement of strain at the nanoscale Type A1 Journal article
Year (down) 2020 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 219 Issue Pages 113099
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Lattice strain measurement of nanoscale semiconductor devices is crucial for the semiconductor industry as strain substantially improves the electrical performance of transistors. High resolution scanning transmission electron microscopy (HR-STEM) imaging is an excellent tool that provides spatial resolution at the atomic scale and strain information by applying Geometric Phase Analysis or image fitting procedures. However, HR-STEM images regularly suffer from scanning distortions and sample drift during image acquisition. In this paper, we propose a new scanning strategy that drastically reduces artefacts due to drift and scanning distortion, along with extending the field of view. It consists of the acquisition of a series of independent small subimages containing an atomic resolution image of the local lattice. All subimages are then analysed individually for strain by fitting a nonlinear model to the lattice images. The method allows flexible tuning of spatial resolution and the field of view within the limits of the dynamic range of the scan engine while maintaining atomic resolution sampling within the subimages. The obtained experimental strain maps are quantitatively benchmarked against the Bessel diffraction technique. We demonstrate that the proposed scanning strategy approaches the performance of the diffraction technique while having the advantage that it does not require specialized diffraction cameras.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000594768500006 Publication Date 2020-09-01
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0304-3991 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.2 Times cited 4 Open Access OpenAccess
Notes A.B. D.J. and J.V. acknowledge funding through FWO project G093417N ('Compressed sensing enabling low dose imaging in transmission electron microscopy') from the Flanders Research Fund. J.V acknowledges funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 823717 – ESTEEM3. The Qu-Ant-EM microscope and the direct electron detector used in the diffraction experiments was partly funded by the Hercules fund from the Flemish Government. This project has received funding from the GOA project “Solarpaint” of the University of Antwerp. GG acknowledges support from a postdoctoral fellowship grant from the Fonds Wetenschappelijk Onderzoek – Vlaanderen (FWO). Special thanks to Dr. Thomas Nuytten, Prof. Dr. Wilfried Vandervorst, Dr. Paola Favia, Dr. Olivier Richard from IMEC, Leuven and Prof. Dr. Sara Bals from EMAT, Antwerp for their continuous support and collaboration with the project and to the IMEC processing group for the device fabrication. Approved Most recent IF: 2.2; 2020 IF: 2.843
Call Number EMAT @ emat @c:irua:172485 Serial 6404
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Author De wael, A.; De Backer, A.; Van Aert, S.
Title Hidden Markov model for atom-counting from sequential ADF STEM images: Methodology, possibilities and limitations Type A1 Journal article
Year (down) 2020 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 219 Issue Pages 113131
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract We present a quantitative method which allows us to reliably measure dynamic changes in the atomic structure of monatomic crystalline nanomaterials from a time series of atomic resolution annular dark field scanning transmission electron microscopy images. The approach is based on the so-called hidden Markov model and estimates the number of atoms in each atomic column of the nanomaterial in each frame of the time series. We discuss the origin of the improved performance for time series atom-counting as compared to the current state-of-the-art atom-counting procedures, and show that the so-called transition probabilities that describe the probability for an atomic column to lose or gain one or more atoms from frame to frame are particularly important. Using these transition probabilities, we show that the method can also be used to estimate the probability and cross section related to structural changes. Furthermore, we explore the possibilities for applying the method to time series recorded under variable environmental conditions. The method is shown to be promising for a reliable quantitative analysis of dynamic processes such as surface diffusion, adatom dynamics, beam effects, or in situ experiments.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000594770500003 Publication Date 2020-10-03
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0304-3991 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.2 Times cited Open Access OpenAccess
Notes This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (Grant Agreement No. 770887 and No. 823717 ESTEEM3). The authors acknowledge financial support from the Research Foundation Flanders (FWO, Belgium) through grants to A.D.w. and A.D.B. and projects G.0502.18N and EOS 30489208. Approved Most recent IF: 2.2; 2020 IF: 2.843
Call Number EMAT @ emat @c:irua:172449 Serial 6417
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Author Gorji, S.; Kashiwar, A.; Mantha, L.S.; Kruk, R.; Witte, R.; Marek, P.; Hahn, H.; Kübel, C.; Scherer, T.
Title Nanowire facilitated transfer of sensitive TEM samples in a FIB Type A1 Journal article
Year (down) 2020 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 219 Issue Pages 113075
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract We introduce a facile approach to transfer thin films and other mechanically sensitive TEM samples inside a FIB with minimal introduction of stress and bending. The method is making use of a pre-synthetized flexible freestanding Ag nanowire attached to the tip of a typical tungsten micromanipulator inside the FIB. The main advantages of this approach are the significantly reduced stress-induced bending during transfer and attachment of the TEM sample, the very short time required to attach and cut the nanowire, the operation at very low dose and ion current, and only using the e-beam for Pt deposition during the transfer of sensitive TEM samples. This results in a reduced sample preparation time and reduced exposure to the ion beam or e-beam for Pt deposition during the sample preparation and thus also reduced contamination and beam damage. The method was applied to a number of thin films and different TEM samples in order to illustrate the advantageous benefits of the concept. In particular, the technique has been successfully tested for the transfer of a thin film onto a MEMS heating chip for in situ TEM experiments.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos Publication Date 2020-07-15
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0304-3991 ISBN Additional Links UA library record
Impact Factor 2.2 Times cited Open Access
Notes Approved Most recent IF: 2.2; 2020 IF: 2.843
Call Number UA @ admin @ c:irua:183618 Serial 6871
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Author Muhammad, S.; Wuyts, K.; Nuyts, G.; De Wael, K.; Samson, R.
Title Characterization of epicuticular wax structures on leaves of urban plant species and its association with leaf wettability Type A1 Journal article
Year (down) 2020 Publication Urban Forestry & Urban Greening Abbreviated Journal Urban For Urban Gree
Volume 47 Issue 47 Pages 126557
Keywords A1 Journal article; Engineering sciences. Technology; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract Epicuticular wax (EW) protects the plant’s integrity and acts as a barrier against biotic and abiotic stresses. The micro-structured three-dimensional EW’s and presence of leaf trichomes influence the wettability of a leaf surface. In this study, leaves of 96 perennial urban plant species were examined to determine an association between epicuticular wax structure (EWS) types and leaf wettability and investigate their seasonal variation. The EWS types were identified using Scanning Electron Microscopy (SEM), while leaf wettability was analyzed by measuring the drop contact angle (DCA) on both the abaxial and the adaxial sides of leaves collected from a common garden in June and September 2016. Four distinct EWS types namely thin film, platelets, crusts, and tubules were observed on leaves of investigated plant species in both June and September. The EWS types varied significantly between functional plant types and plant families in both June and September. In June, the abaxial DCA ranged from 56° to 147°, and the adaxial DCA ranged from 56° to 136°. In September, the abaxial DCA ranged from 54° to 130°, and the adaxial DCA ranged from 51° to 125°. The effect of time, leaf side, and EWS type on leaf wettability were significant. Plant species which showed a change in EWS type or clustering from June to September did not show a more pronounced reduction in DCA compared to those species which exhibited a constant EWS type. Findings from our study illustrate that DCA is not a good indicator in determining the different EWS types due to overlapping DCA intervals between the identified EWS types. However, the identified EWS types remained fairly stable throughout the in-leaf season and do not require repeated measurements for characterization.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000508389000028 Publication Date 2019-12-05
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1618-8667 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.4 Times cited 5 Open Access
Notes ; The research was funded by the Ontario Student Assistance Program (OSAP # 15103399). The SEM equipment was funded by FWO/Hercules. The authors acknowledge the help of the ENdEMIC group involved in the upkeep of the experimental site. The authors would like to thank the anonymous reviewers for their critical comments and constructive suggestions in improving the quality of the article. ; Approved Most recent IF: 6.4; 2020 IF: 2.113
Call Number UA @ admin @ c:irua:164906 Serial 5504
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Author Koch, K.; Ysebaert, T.; Denys, S.; Samson, R.
Title Urban heat stress mitigation potential of green walls: A review Type A1 Journal article
Year (down) 2020 Publication Urban Forestry & Urban Greening Abbreviated Journal Urban For Urban Gree
Volume 55 Issue Pages 126843-13
Keywords A1 Journal article; Engineering sciences. Technology; Art; Sustainable Energy, Air and Water Technology (DuEL)
Abstract Cities with resilience to climate change appear to be a vision of the future, but are inevitable to ensure the quality of life for citizens and to avoid an increase in civilian mortality. Urban green infrastructure (UGI), with the focus on vertical green, poses a beneficial mitigation and adaptation strategy for challenges such as climate change through cooling effects on building and street level. This review article explores recent literature regarding this considerable topic and investigates how green walls can be applied to mitigate this problem. Summary tables (see additional information) and figures are presented that can be used by policy makers and researchers to make informed decisions when installing green walls in built-up environments. At last, knowledge gaps are uncovered that need further investigation to exploit the benefits at its best.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000593921600001 Publication Date 2020-09-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1618-8667 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.4 Times cited Open Access
Notes Approved Most recent IF: 6.4; 2020 IF: 2.113
Call Number UA @ admin @ c:irua:172985 Serial 6650
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Author Geerts, R.; Vandermoere, F.; Halet, D.; Van Winckel, T.; Joos, P.; Van Den Steen, K.; Van Meenen, E.; Blust, R.; Vlaeminck, S.E.
Title Ik drink (geen) afval! Een exploratieve studie naar socio-demografische verschillen in publieke steun voor het hergebruik van afvalwater in Vlaanderen Type A1 Journal article
Year (down) 2020 Publication Vlaams tijdschrift voor overheidsmanagement Abbreviated Journal
Volume Issue 3 Pages 51-69
Keywords A1 Journal article; Sociology; Sustainable Energy, Air and Water Technology (DuEL); Centre for Research on Environmental and Social Change
Abstract In een context van stijgende waterschaarste verkennen wij, naar ons weten voor het eerst in Vlaanderen, publieke steun voor de behandeling en het hergebruik van afvalwater als drinkwater. Vlaanderen is vandaag een van de weinige regio’s waar afvalwater reeds gerecycleerd wordt voor drinkwaterdoeleinden. Dit gebeurt op kleinschalig niveau en de uitbreiding hiervan is vandaag een van de Vlaamse beleidsdoelstellingen. Internationale voorbeelden toonden echter dat een gebrek aan publieke steun een aanzienlijk obstakel kan zijn. Vaak worden gezondheids- en veiligheidsbezorgdheden aangehaald als oorzaak voor het beperkte draagvlak. Minder is geweten over de socio-demografische distributie van dit draagvlak. Daarbovenop blijft er onduidelijkheid over de samenhang tussen socio-demografische kenmerken en gezondheids- en veiligheidsbezorgdheden. Met behulp van een enquête uitgevoerd in Vlaanderen (N=2309), bestudeerden wij ten eerste deze socio-demografische verschillen op basis van bivariate associaties (gender, opleidingsniveau, leeftijd en woonplaats). Ten tweede construeerden we een padmodel om te onderzoeken of deze verschillen verklaard kunnen worden aan de hand van gezondheids- en veiligheidsbezorgdheden. Onze resultaten toonden dat publieke steun voor afvalwaterhergebruik voor drinkwaterdoeleinden in Vlaanderen beperkt is. Het draagvlak was het laagst bij oudere mensen, vrouwen, lager geschoolde groepen en mensen die niet in de Provincie Antwerpen wonen. Voor een groot deel konden socio-demografische verschillen verklaard worden door hogere gezondheids- en veiligheidsbezorgdheden bij vrouwen, lager geschoolden en mensen uit West- en Oost-Vlaanderen. Dit suggereert een gebrek aan vertrouwen in waterexperts en -technologie bij bepaalde socio-demografische groepen, wat zich vertaalt in een verminderde publieke steun voor afvalwaterhergebruik. Op basis van deze bevindingen bespreken we een aantal potentiële actiestrategieën om publieke oppositie te anticiperen en proactief publieke steun te verwerven via doelgerichte (risico)communicatie.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos Publication Date
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1373-0509 ISBN Additional Links UA library record
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:171478 Serial 6541
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Author Vandekerckhove, T.G.L.; Props, R.; Carvajal-Arroyo, J.M.; Boon, N.; Vlaeminck, S.E.
Title Adaptation and characterization of thermophilic anammox in bioreactors Type A1 Journal article
Year (down) 2020 Publication Water Research Abbreviated Journal Water Res
Volume 172 Issue Pages 115462
Keywords A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Abstract Anammox, the oxidation of ammonium with nitrite, is a key microbial process in the nitrogen cycle. Under mesophilic conditions (below 40 °C), it is widely implemented to remove nitrogen from wastewaters lacking organic carbon. Despite evidence of the presence of anammox bacteria in high-temperature environments, reports on the cultivation of thermophilic anammox bacteria are limited to a short-term experiment of 2 weeks. This study showcases the adaptation of a mesophilic inoculum to thermophilic conditions, and its characterization. First, an attached growth technology was chosen to obtain the process. In an anoxic fixed-bed biofilm bioreactor (FBBR), a slow linear temperature increase from 38 to over 48 °C (0.05–0.07 °C d−1) was imposed to the community over 220 days, after which the reactor was operated at 48 °C for over 200 days. Maximum total nitrogen removal rates reached up to 0.62 g N L−1 d−1. Given this promising performance, a suspended growth system was tested. The obtained enrichment culture served as inoculum for membrane bioreactors (MBR) operated at 50 °C, reaching a maximum total nitrogen removal rate of 1.7 g N L−1 d−1 after 35 days. The biomass in the MBR had a maximum specific anammox activity of 1.1 ± 0.1 g NH4+-N g−1 VSS d−1, and the growth rate was estimated at 0.075–0.19 d−1. The thermophilic cultures displayed nitrogen stoichiometry ratios typical for mesophilic anammox: 0.93–1.42 g NO2--Nremoved g−1 NH4+-Nremoved and 0.16–0.35 g NO3--Nproduced g−1 NH4+-Nremoved. Amplicon and Sanger sequencing of the 16S rRNA genes revealed a disappearance of the original “Ca. Brocadia” and “Ca. Jettenia” taxa, yielding Planctomycetes members with only 94–95% similarity to “Ca. Brocadia anammoxidans” and “Ca. B. caroliniensis”, accounting for 45% of the bacterial FBBR community. The long-term operation of thermophilic anammox reactors and snapshot views on the nitrogen stoichiometry, kinetics and microbial community open up the development path of thermophilic partial nitritation/anammox. A first economic assessment highlighted that treatment of sludge reject water from thermophilic anaerobic digestion of sewage sludge may become attractive.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000517663600014 Publication Date 2020-01-10
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0043-1354 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 12.8 Times cited 5 Open Access
Notes ; The authors acknowledge (i) the Agency for Innovation by Science and Technology (IWT Flanders) [grant number SB-141205] for funding T.G.L.V., (ii) Ghent University (BOFDOC2015000601) and the Belgian Nuclear Research Centre (SCK.CEN) for funding R.P., (iii) Bart De Gusseme from Farys/UGent for providing the hollow fiber membranes, (iv) Tim Lacoere for performing the DNA extraction and data processing of the Sanger sequencing and 16S rRNA gene amplicon sequencing data, (v) Tim Hendrickx from Paques BV for providing the inoculum, (vi) Bert Bundervoet and Wim Groen in 't Woud from Colsen for the valuable input on the economic assessment and (vii) Joop Colsen, Stijn Van Hulle, Mark Van Loosdrecht, Erik Smolders and Leen De Gelder for their constructive discussions on this work. ; Approved Most recent IF: 12.8; 2020 IF: 6.942
Call Number UA @ admin @ c:irua:165392 Serial 6449
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Author De Paepe, J.; De Paepe, K.; Gòdia, F.; Rabaey, K.; Vlaeminck, S.E.; Clauwaert, P.
Title Bio-electrochemical COD removal for energy-efficient, maximum and robust nitrogen recovery from urine through membrane aerated nitrification Type A1 Journal article
Year (down) 2020 Publication Water Research Abbreviated Journal Water Res
Volume 185 Issue Pages 116223
Keywords A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Abstract Resource recovery from source-separated urine can shorten nutrient cycles on Earth and is essential in regenerative life support systems for deep-space exploration. In this study, a robust two-stage, energy-efficient, gravity-independent urine treatment system was developed to transform fresh real human urine into a stable nutrient solution. In the first stage, up to 85% of the COD was removed in a microbial electrolysis cell (MEC), converting part of the energy in organic compounds (27-46%) into hydrogen gas and enabling full nitrogen recovery by preventing nitrogen losses through denitrification in the second stage. Besides COD removal, all urea was hydrolysed in the MEC, resulting in a stream rich in ammoniacal nitrogen and alkalinity, and low in COD. This stream was fed into a membrane-aerated biofilm reactor (MABR) in order to convert the volatile and toxic ammoniacal nitrogen to non-volatile nitrate by nitrification. Bio-electrochemical pre-treatment allowed to recover all nitrogen as nitrate in the MABR at a bulk-phase dissolved oxygen level below 0.1 mg O2 L-1. In contrast, feeding the MABR directly with raw urine (omitting the first stage), at the same nitrogen loading rate, resulted in nitrogen loss (18%) due to denitrification. The MEC and MABR were characterised by very distinct and diverse microbial communities. While (strictly) anaerobic genera, such as Geobacter (electroactive bacteria), Thiopseudomonas, a Lentimicrobiaceae member, Alcaligenes and Proteiniphilum prevailed in the MEC, the MABR was dominated by aerobic genera, including Nitrosomonas (a known ammonium oxidiser), Moheibacter and Gordonia. The two-stage approach yielded a stable nitrate-rich, COD-low nutrient solution, suitable for plant and microalgae cultivation.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000580639800035 Publication Date 2020-07-23
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0043-1354 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 12.8 Times cited Open Access
Notes Approved Most recent IF: 12.8; 2020 IF: 6.942
Call Number UA @ admin @ c:irua:170524 Serial 6461
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Author Geerts, R.; Vandermoere, F.; Van Winckel, T.; Halet, D.; Joos, P.; Van Den Steen, K.; Van Meenen, E.; Blust, R.; Borregán-Ochando, E.; Vlaeminck, S.E.
Title Bottle or tap? Toward an integrated approach to water type consumption Type A1 Journal article
Year (down) 2020 Publication Water Research Abbreviated Journal Water Res
Volume 173 Issue Pages 115578-10
Keywords A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL); Centre for Research on Environmental and Social Change
Abstract While in many countries, people have access to cheap and safe potable tap water, the global consumption of bottled water is rising. Flanders, Belgium, where this study is located, has an exceptionally high consumption of bottled water per capita. However, in the interest of resource efficiency and global environmental challenges, the consumption of tap water is preferable. To our knowledge, an integrated analysis of the main reasons why people consume tap and bottled water is absent in Flanders, Belgium. Using Flemish survey data (N = 2309), we first compared tap and bottled water consumers through bivariate correlation analysis. Subsequently, path modelling techniques were used to further investigate these correlations. Our results show that bottled water consumption in Flanders is widespread despite environmental and financial considerations. For a large part, this is caused by negative perceptions about tap water. Many consumers consider it unhealthy, unsafe and prefer the taste of bottled water. Furthermore, we found that the broader social context often inhibits the consumption of tap water. On the one hand, improper infrastructures (e.g. lead piping) can limit access to potable tap water. On the other hand, social norms exist that promote bottled water. Lastly, results suggest that the consumption of bottled water is most common among men, older people and less educated groups. We conclude that future research and policy measures will benefit from an approach that integrates all behavioural aspects associated with water type consumption. This will enable both governments and tap water companies to devise more effective policies to manage and support tap water supply networks.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000523569000012 Publication Date 2020-01-31
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0043-1354 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 12.8 Times cited 2 Open Access
Notes ; This was supported by a grant from Water-link. ; Approved Most recent IF: 12.8; 2020 IF: 6.942
Call Number UA @ admin @ c:irua:165873 Serial 6464
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Author Spiller, M.; Muys, M.; Papini, G.; Sakarika, M.; Buyle, M.; Vlaeminck, S.E.
Title Environmental impact of microbial protein from potato wastewater as feed ingredient : comparative consequential life cycle assessment of three production systems and soybean meal Type A1 Journal article
Year (down) 2020 Publication Water Research Abbreviated Journal Water Res
Volume 171 Issue Pages 115406
Keywords A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL); Energy and Materials in Infrastructure and Buildings (EMIB)
Abstract Livestock production is utilizing large amounts of protein-rich feed ingredients such as soybean meal. The proven negative environmental impacts of soybean meal production incentivize the search for alternative protein sources. One promising alternative is Microbial Protein (MP), i.e. dried microbial biomass. To date, only few life cycle assessments (LCAs) for MP have been carried out, none of which has used a consequential modelling approach nor has been investigating the production of MP on food and beverage wastewater. Therefore, the objective of this study is to evaluate the environmental impact of MP production on a food and beverage effluent as a substitute for soybean meal using a consequential modelling approach. Three different types of MP production were analysed, namely consortia containing Aerobic Heterotrophic Bacteria (AHB), Microalgae and AHB (MaB), and Purple Non-Sulfur Bacteria (PNSB). The production of MP was modelled for high-strength potato wastewater (COD = 10 kg/m3) at a flow rate of 1,000 m3/day. LCA results were compared against soybean meal production for the endpoint impact categories human health, ecosystems, and resources. Soybean meal showed up to 52% higher impact on human health and up to 87% higher impact on ecosystems than MP. However, energy-related aspects resulted in an 8–88% higher resource exploitation for MP. A comparison between the MP production systems showed that MaB performed best when considering ecosystems (between 13 and 14% better) and resource (between 71 and 80% better) impact categories, while AHB and PNSB had lower values for the impact category human health (8–12%). The sensitivity analysis suggests that the conclusions drawn are robust as in the majority of 1,000 Monte Carlo runs the initial results are confirmed. In conclusion, it is suggested that MP is an alternative protein source of comparatively low environmental impact that should play a role in the future protein transition, in particular when further process improvements can be implemented and more renewable or waste energy sources will be used.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000514748900032 Publication Date 2019-12-18
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0043-1354 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 12.8 Times cited 10 Open Access
Notes ; The authors would like to thank (i) the MIP i-Cleantech Flanders (Milieu innovatieplatform; Environment innovation platform) project Microbial Nutrients on Demand (MicroNOD; 150360) for financial support, (ii) the Research Foundation Flanders (FWO-Vlaanderen) for supporting Gustavo Papini with a doctoral fellowship (strategic basic research; 1S38917N), (iii) Research Foundation Flanders (FWO-Vlaanderen) for supporting Matthias Buyle with a post-doctoral fellowship (Postdoctoral Fellow junior; 1207520N), and (iv) Bo Weidema, Abbas Alloul, Yixing Sui and Tim Van Winckel for their insightful discussions. ; Approved Most recent IF: 12.8; 2020 IF: 6.942
Call Number UA @ admin @ c:irua:164944 Serial 6509
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Author Cagno, S.; van der Snickt, G.; Legrand, S.; Caen, J.; Patin, M.; Meulebroeck, W.; Dirkx, Y.; Hillen, M.; Steenackers, G.; Rousaki, A.; Vandenabeele, P.; Janssens, K.
Title Comparison of four mobile, non‐invasive diagnostic techniques for differentiating glass types in historical leaded windows : MA‐XRF , UV–Vis–NIR, Raman spectroscopy and IRT Type A1 Journal article
Year (down) 2020 Publication X-Ray Spectrometry Abbreviated Journal X-Ray Spectrom
Volume Issue Pages xrs.3185-17
Keywords A1 Journal article; Engineering sciences. Technology; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Antwerp Cultural Heritage Sciences (ARCHES)
Abstract This paper critically compares the performance of four non-invasive techniques that match the accuracy, flexibility, time-efficiency, and transportability required for in situ characterization of leaded glass windows: macroscopic X-ray fluorescence imaging (MA-XRF), UV-Vis-NIR, Raman spectroscopy, and infrared thermography (IRT). In order to compare the techniques on equal grounds, all techniques were tested independently of each other by separate research groups on the same historical leaded window tentatively dated to the 17th century, without prior knowledge. The aim was to assess the ability of these techniques to document the conservation history of the window by classifying and grouping the colorless glass panes, based on differences in composition. IRT, MA-XRF and UV-Vis-NIR spectroscopy positively distinguished at least two glass groups, with MA-XRF providing the most detailed chemical information. In particular, based on the ratio between the network modifier (K) and network stabilizer (Ca) and on the level of colorants and decolorizers (Fe, Mn, As), the number of plausible glass families could be strongly reduced. In addition, UV-Vis-NIR detected cobalt at ppm level and gave more specific information on the chromophore Fe2+/Fe(3+)ratio. Raman spectroscopy was hampered by fluorescence caused by the metal ions of the decolorizer in most of the panes, but nevertheless identified one group as HLLA.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000561869600001 Publication Date 2020-08-24
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0049-8246 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.2 Times cited Open Access
Notes ; Belgian Federal Science Policy Office, Grant/Award Number: BR/175/A3/FENESTRA; Fonds Wetenschappelijk Onderzoek, Grant/Award Number: 12X1919N; Baillet-Latour Fund ; Approved Most recent IF: 1.2; 2020 IF: 1.298
Call Number UA @ admin @ c:irua:170972 Serial 6473
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Author Asfora, V.K.; Bueno, C.C.; de Barros, V.M.; Khoury, H.; Van Grieken, R.
Title X-ray spectrometry applied for characterization of bricks of Brazilian historical sites Type A1 Journal article
Year (down) 2020 Publication X-Ray Spectrometry Abbreviated Journal X-Ray Spectrom
Volume Issue Pages 1-8
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract This paper presents the results of X-ray fluorescence (XRF) analysis of bricks sampled from historical places in Pernambuco, a state in the northeastern region of Brazil. In this study, twenty bricks found in historical sites were analyzed. Two bricks made in the 17th century, presumably used as ballast in ships coming from Holland, five locally manufactured bricks: one from 18th century, three from 19th century, and one from 20th century, and thirteen bricks collected from a recent Archeological investigation of Alto da Se, in the town of Olinda. Qualitative determination of the chemical elements present in the samples was undertaken using a self-assembled portable XRF system based on a compact X-ray tube and a thermoelectrically cooled Si-PIN photodiode system, both commercially available. X-ray diffraction analysis was also carried out to assess the crystalline mineral phases present in the bricks. The results showed that quartz (SiO2) is the major mineral content in all bricks. Although less expressive in the XRD patterns, mineral phases of illite, kaolinite, anorthite, and rutile are also identified. The trace element distribution patterns of the bricks, determined by the XRF technique, is dominated by Fe and, in decreasing order, by K, Ti, Ca, Mn, Zr, Rb, Sr, Cr, and Y with slight differences among them. Analyses of the chemical compositional features of the bricks, evaluated by principal component analysis of the XRF datasets, allowed the samples to be grouped into five clusters with similar chemical composition. These cluster groups were able to identify both age and manufacturing sites. Dutch bricks prepared with different geological clays compositions were defined.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000568830300001 Publication Date 2020-09-17
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0049-8246 ISBN Additional Links UA library record; WoS full record
Impact Factor 1.2 Times cited Open Access
Notes ; The authors are grateful to CNPQ (Process: 305903/2011-0 and 407458/2013-1) for providing funds to carry out the present work and for supporting a visitor professor to UFPE through the program science without frontier. The authors also thank Mr. Roberto Araujo from the Center of Advanced Studies on Integrated Environmental Protection-CECI that made available the bricks to be analyzed. ; Approved Most recent IF: 1.2; 2020 IF: 1.298
Call Number UA @ admin @ c:irua:171960 Serial 6654
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Author Tiwari, S.; Van de Put, M.L.; Sorée, B.; Vandenberghe, W.G.
Title Carrier transport in two-dimensional topological insulator nanoribbons in the presence of vacancy defects Type A1 Journal article
Year (down) 2019 Publication 2D materials Abbreviated Journal 2D Mater
Volume 6 Issue 2 Pages 025011
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Using the non-equilibrium Green's function formalism, we study carrier transport through imperfect two-dimensional (2D) topological insulator (TI) ribbons. In particular, we investigate the effect of vacancy defects on the carrier transport in 2D TI ribbons with hexagonal lattice structure. To account for the random distribution of the vacancy defects, we present a statistical study of varying defect densities by stochastically sampling different defect configurations. We demonstrate that the topological edge states of TI ribbons are fairly robust against a high concentration (up to 2%) of defects. At very high defect densities, we observe an increased inter-edge interaction, mediated by the localisation of the edge states within the bulk region. This effect causes significant back-scattering of the, otherwise protected, edge-states at very high defect concentrations (>2%), resulting in a loss of conduction through the TI ribbon. We discuss how this coherent vacancy scattering can be used to our advantage for the development of TI-based transistors. We find that there is an optimal concentration of vacancies yielding an ON-OFF current ratio of up to two orders of magnitude. Finally, we investigate the importance of spin-orbit coupling on the robustness of the edge states in the TI ribbon and show that increased spin-orbit coupling could further increase the ON-OFF ratio.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000457856400002 Publication Date 2019-01-22
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2053-1583 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.937 Times cited 3 Open Access
Notes ; This material is based in part upon work supported by the National Science Foundation under Grant Number 1710066. The project or effort depicted was or is sponsored by the Department of Defense, Defense Threat Reduction Agency. The content of the information does not necessarily reflect the position or the policy of the federal government, and no official endorsement should be inferred. This work was supported by imec's Industrial Affiliation Program. ; Approved Most recent IF: 6.937
Call Number UA @ admin @ c:irua:157464 Serial 5198
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Author Li, L.L.; Partoens, B.; Xu, W.; Peeters, F.M.
Title Electric-field modulation of linear dichroism and Faraday rotation in few-layer phosphorene Type A1 Journal article
Year (down) 2019 Publication 2D materials Abbreviated Journal 2D Mater
Volume 6 Issue 1 Pages 015032
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Electro-optical modulators, which use an electric voltage (or an electric field) to modulate a beam of light, are essential elements in present-day telecommunication devices. Using a self-consistent tight-binding approach combined with the standard Kubo formula, we show that the optical conductivity and the linear dichroism of few-layer phosphorene can be modulated by a perpendicular electric field. We find that the field-induced charge screening plays a significant role in modulating the optical conductivity and the linear dichroism. Distinct absorption peaks are induced in the conductivity spectrum due to the strong quantum confinement along the out-of-plane direction and to the field-induced forbidden-to-allowed transitions. The field modulation of the linear dichroism becomes more pronounced with increasing number of phosphorene layers. We also show that the Faraday rotation is present in few-layer phosphorene even in the absence of an external magnetic field. This optical Hall effect is induced by the reduced lattice symmetry of few-layer phosphorene. The Faraday rotation is greatly influenced by the field-induced charge screening and is strongly dependent on the strength of perpendicular electric field and on the number of phosphorene layers.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000454321100002 Publication Date 2018-11-28
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2053-1583 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.937 Times cited 23 Open Access
Notes ; This work was financially supported by the Flemish Science Foundation (FWO-Vl) and by the FLAG-ERA project TRANS-2D-TMD. ; Approved Most recent IF: 6.937
Call Number UA @ admin @ c:irua:156776 Serial 5207
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Author Heyne, M.H.; Marinov, D.; Braithwaite, N.; Goodyear, A.; de Marneffe, J.-F.; Cooke, M.; Radu, I.; Neyts, E.C.; De Gendt, S.
Title A route towards the fabrication of 2D heterostructures using atomic layer etching combined with selective conversion Type A1 Journal article
Year (down) 2019 Publication 2D materials Abbreviated Journal 2D Mater
Volume 6 Issue 3 Pages 035030
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Heterostructures of low-dimensional semiconducting materials, such as transition metal dichalcogenides (MX2), are promising building blocks for future electronic and optoelectronic devices. The patterning of one MX2 material on top of another one is challenging due to their structural similarity. This prevents an intrinsic etch stop when conventional anisotropic dry etching processes are used. An alternative approach consist in a two-step process, where a sacrificial silicon layer is pre-patterned with a low damage plasma process, stopping on the underlying MoS2 film. The pre-patterned layer is used as sacrificial template for the formation of the top WS2 film. This study describes the optimization of a cyclic Ar/Cl-2 atomic layer etch process applied to etch silicon on top of MoS2, with minimal damage, followed by a selective conversion of the patterned Si into WS2. The impact of the Si atomic layer etch towards the MoS2 is evaluated: in the ion energy range used for this study, MoS2 removal occurs in the over-etch step over 1-2 layers, leading to the appearance of MoOx but without significant lattice distortions to the remaining layers. The combination of Si atomic layer etch, on top of MoS2, and subsequent Si-to-WS2 selective conversion, allows to create a WS2/MoS2 heterostructure, with clear Raman signals and horizontal lattice alignment. These results demonstrate a scalable, transfer free method to achieve horizontally individually patterned heterostacks and open the route towards wafer-level processing of 2D materials.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000468335500004 Publication Date 2019-04-23
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2053-1583 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.937 Times cited Open Access Not_Open_Access
Notes Approved Most recent IF: 6.937
Call Number UA @ admin @ c:irua:160229 Serial 5266
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Author Van Pottelberge, R.; Moldovan, D.; Milovanović, S.P.; Peeters, F.M.
Title Molecular collapse in monolayer graphene Type A1 Journal article
Year (down) 2019 Publication 2D materials Abbreviated Journal 2D Mater
Volume 6 Issue 4 Pages 045047
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Atomic collapse is a phenomenon inherent to relativistic quantum mechanics where electron states dive in the positron continuum for highly charged nuclei. This phenomenon was recently observed in graphene. Here we investigate a novel collapse phenomenon when multiple sub- and supercritical charges of equal strength are put close together as in a molecule. We construct a phase diagram which consists of three distinct regions: (1) subcritical, (2) frustrated atomic collapse, and (3) molecular collapse. We show that the single impurity atomic collapse resonances rearrange themselves to form molecular collapse resonances which exhibit a distinct bonding, anti-bonding and non-bonding character. Here we limit ourselves to systems consisting of two and three charges. We show that by tuning the distance between the charges and their strength a high degree of control over the molecular collapse resonances can be achieved.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000487692200003 Publication Date 2019-08-30
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2053-1583 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.937 Times cited 10 Open Access
Notes ; We thank Matthias Van der Donck for fruitful discussions. This work was supported by the Research Foundation of Flanders (FWO-V1) through an aspirant research Grant for RVP and a postdoctoral Grant for SPM. ; Approved Most recent IF: 6.937
Call Number UA @ admin @ c:irua:163756 Serial 5422
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Author Osella, S.; Knippenberg, S.
Title Laurdan as a molecular rotor in biological environments Type A1 Journal article
Year (down) 2019 Publication ACS applied bio materials Abbreviated Journal
Volume 2 Issue 12 Pages 5769-5778
Keywords A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Laurdan is one of the most used fluorescent probes for lipid membrane phase recognition. Despite its wide use for optical techniques and its versatility as a solvatochromic probe, little is known regarding its use as molecular rotor, for which clear evidence is found in the current study. Although recent computational and experimental studies suggest the existence of two stable conformations of laurdan in different membrane phases, it is difficult to experimentally probe their prevalence. By means of multiscale computational approaches, we prove now that this information can be obtained through the optical properties of the two conformers, ranging from one-photon absorption over two-photon absorption to the first hyperpolarizability. Fluorescence decay and anisotropy analyses are performed as well and stress the importance of laurdan's conformational versatility. As a molecular rotor and with reference to the distinct properties of its conformers, laurdan can be used to probe biochemical processes that change the lipid orders in cell membranes.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000616372300047 Publication Date 2019-11-22
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2576-6422 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited Open Access
Notes Approved no
Call Number UA @ admin @ c:irua:180356 Serial 8166
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Author Siriwardane, E.M.D.; Demiroglu, I.; Sevik, C.; Cakir, D.
Title Achieving Fast Kinetics and Enhanced Li Storage Capacity for Ti3C2O2 by Intercalation of Quinone Molecules Type A1 Journal article
Year (down) 2019 Publication ACS applied energy materials Abbreviated Journal
Volume 2 Issue 2 Pages 1251-1258
Keywords A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Abstract Using first-principles calculations, we demonstrated that high lithium storage capacity and fast kinetics are achieved for Ti3C2O2 by preintercalating organic molecules. As a proof-of-concept, two different quinone molecules, namely 1,4-benzoquinone (C6H4O2) and tetrafluoro-1,4-benzoquinone (C6F4O2) were selected as the molecular linkers to demonstrate the feasibility of this interlayer engineering strategy for energy storage. As compared to Ti3C2O2 bilayer without linker molecules, our pillared structures facilitate a much faster ion transport, promising a higher charge/discharge rate for Li. For example, while the diffusion barrier of a single Li ion within pristine Ti3C2O2 bilayer is at least 1.0 eV, it becomes 0.3 eV in pillared structures, which is comparable and even lower than that of commercial materials. At high Li concentrations, the calculated diffusion barriers are as low as 0.4 eV. Out-of-plane migration of Li ions is hindered due to large barrier energy with a value of around 1-1.35 eV. Concerning storage capacity, we can only intercalate one monolayer of Li within pristine Ti3C2O2 bilayer. In contrast, pillared structures offer significantly higher storage capacity. Our calculations showed that at least two layers of Li can be intercalated between Ti3C2O2 layers without forming bulk Li and losing the pillared structure upon Li loading/unloading. A small change in the in-plane lattice parameters (<0.5%) and volume (<1.0%) and ab initio molecular dynamics simulations prove the stability of the pillared structures against Li intercalation and thermal effects. Intercalated molecules avoid the large contraction/expansion of the whole structure, which is one of the key problems in electrochemical energy storage. Pillared structures allow us to realize electrodes with high capacity and fast kinetics. Our results open new research paths for improving the performance of not only MXenes but also other layered materials for supercapacitor and battery applications.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000459948900037 Publication Date 2019-01-04
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2574-0962 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited Open Access
Notes Approved no
Call Number UA @ admin @ c:irua:193759 Serial 7414
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Author Gasparotto, A.; Maccato, C.; Carraro, G.; Sada, C.; Štangar, U.L.; Alessi, B.; Rocks, C.; Mariotti, D.; La Porta, A.; Altantzis, T.; Barreca, D.
Title Surface Functionalization of Grown-on-Tip ZnO Nanopyramids: From Fabrication to Light-Triggered Applications Type A1 Journal Article
Year (down) 2019 Publication Acs Applied Materials & Interfaces Abbreviated Journal Acs Appl Mater Inter
Volume 11 Issue 17 Pages 15881-15890
Keywords A1 Journal Article; Electron Microscopy for Materials Science (EMAT) ;
Abstract We report on a combined chemical vapor deposition (CVD)/radio frequency (RF) sputtering synthetic strategy for the controlled surface modification of ZnO nanostructures by Ti-containing species. Specifically, the proposed approach consists in the CVD of grown-on-tip ZnO nanopyramids, followed by titanium RF sputtering under mild conditions. The results obtained by a thorough characterization demonstrate the successful ZnO surface functionalization with dispersed Ti-containing species in low amounts. This phenomenon, in turn, yields a remarkable enhancement of photoactivated superhydrophilic behavior, self-cleaning ability, and photocatalytic performances in comparison to bare ZnO. The reasons accounting for such an improvement are unravelled by a multitechnique analysis, elucidating the interplay between material chemico-physical properties and the corresponding functional behavior. Overall, the proposed strategy stands as an amenable tool for the mastering of semiconductor-based functional nanoarchitectures through ad hoc engineering of the system surface.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000466988800078 Publication Date 2019-04-18
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1944-8244 ISBN Additional Links
Impact Factor 7.504 Times cited 1 Open Access Not_Open_Access
Notes The research leading to these results has received financial support from Padova University ACTION postdoc fellowship, DOR 2016-2018, P-DiSC #03BIRD2016-UNIPD projects, and HERALD COST Action MP1402-37831. The support from EPSRC (awards EP/R008841/1 and EP/M024938/1) as well as from the Slovenian Research Agency (research core funding No. P1-0134) is also recognized. T.A. acknowledges a postdoctoral grant from the Research Foundation Flanders (FWO, Belgium). The authors are grateful to Dr. Sebastiano Pianta (Department of Chemical Sciences, Padova University, Italy) for experimental assistance. Approved Most recent IF: 7.504
Call Number EMAT @ emat @ Serial 5185
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Author Retuerto, M.; Calle-Vallejo, F.; Pascual, L.; Lumbeeck, G.; Fernandez-Diaz, M.T.; Croft, M.; Gopalakrishnan, J.; Pena, M.A.; Hadermann, J.; Greenblatt, M.; Rojas, S.
Title La1.5Sr0.5NiMn0.5Ru0.5O6 double perovskite with enhanced ORR/OER bifunctional catalytic activity Type A1 Journal article
Year (down) 2019 Publication ACS applied materials and interfaces Abbreviated Journal Acs Appl Mater Inter
Volume 11 Issue 24 Pages 21454-21464
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract Perovskites (ABO(3)) with transition metals in active B sites are considered alternative catalysts for the water oxidation to oxygen through the oxygen evolution reaction (OER) and for the oxygen reduction through the oxygen reduction reaction (ORR) back to water. We have synthesized a double perovskite (A(2)BB'O-6) with different cations in A, B, and B' sites, namely, ((La15Sr0.5)-Sr-.)(A)(Ni0.5Mn0.5)(B)(Ni0.5Ru0.5)(B)O-6 (LSNMR), which displays an outstanding OER/ORR bifunctional performance. The composition and structure of the oxide has been determined by powder X-ray diffraction, powder neutron diffraction, and transmission electron microscopy to be monoclinic with the space group P2(1)/n and with cationic ordering between the ions in the B and B' sites. X-ray absorption near-edge spectroscopy suggests that LSNMR presents a configuration of similar to Ni2+, similar to Mn4+, and similar to Ru5+. This bifunctional catalyst is endowed with high ORR and OER activities in alkaline media, with a remarkable bifunctional index value of similar to 0.83 V (the difference between the potentials measured at -1 mA cm(-2) for the ORR and +10 mA cm(-2) for the OER). The ORR onset potential (E-onset) of 0.94 V is among the best reported to date in alkaline media for ORR-active perovskites. The ORR mass activity of LSNMR is 1.1 A g(-1) at 0.9 V and 7.3 A g(-1) at 0.8 V. Furthermore, LSNMR is stable in a wide potential window down to 0.05 V. The OER potential to achieve a current density of 10 mA cm(-2) is 1.66 V. Density functional theory calculations demonstrate that the high ORR/OER activity of LSNMR is related to the presence of active Mn sites for the ORR- and Ru-active sites for the OER by virtue of the high symmetry of the respective reaction steps on those sites. In addition, the material is stable to ORR cycling and also considerably stable to OER cycling.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000472683300019 Publication Date 2019-05-30
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1944-8244 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 7.504 Times cited 12 Open Access
Notes ; This work was supported by the ENE2016-77055-C3-3-R project from the Spanish Ministry of Economy and Competitiveness (MINECO) and PIE 201480E122 from CSIC. M.R. thanks MINECO's Juan de la Cierva program for a grant (FPDI-2013-17582). F.C.-V. thanks the Spanish MEC for a Ramon y Cajal research contract (RYC-2015-18996). M.G. acknowledges the support from NSF-DMR-1507252 grant, NJ, USA. ; Approved Most recent IF: 7.504
Call Number UA @ admin @ c:irua:161320 Serial 5400
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Author Peeters, B.; Daems, D.; Van der Donck, T.; Delport, F.; Lammertyn, J.
Title Real-time FO-SPR monitoring of solid-phase DNAzyme cleavage activity for cutting-edge biosensing Type A1 Journal article
Year (down) 2019 Publication ACS applied materials and interfaces Abbreviated Journal
Volume 11 Issue 7 Pages 6759-6768
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract DNA nanotechnology has a great potential in biosensor design including nanostructuring of the biosensor surface through DNA origami, target recognition by means of aptamers, and DNA-based signal amplification strategies. In this paper, we use DNA nanotechnology to describe for the first time the concept of real-time solid-phase monitoring of DNAzyme cleavage activity for the detection of specific single-stranded DNA (ssDNA) with a fiber optic surface plasmon resonance (FO-SPR) biosensor. Hereto, we first developed a robust ligation strategy for the functionalization of the FO-SPR biosensing surface with ssDNA-tethered gold nanoparticles, serving as the substrate for the DNAzyme. Next, we established a relation between the SPR signal change, due to the cleavage activity of the 10–23 DNAzyme, and the concentration of the DNAzyme, showing faster cleavage kinetics for higher DNAzyme concentrations. Finally, we implemented this generic concept for biosensing of ssDNA target in solution. Hereto, we designed a DNAzyme–inhibitor complex, consisting of an internal loop structure complementary to the ssDNA target, that releases active DNAzyme molecules in a controlled way as a function of the target concentration. We demonstrated reproducible target detection with a theoretical limit of detection of 1.4 nM, proving that the presented ligation strategy is key to a universal DNAzyme-based FO-SPR biosensing concept with promising applications in the medical and agrofood sector.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000459642200008 Publication Date 2019-01-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1944-8244 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited Open Access
Notes Approved no
Call Number UA @ admin @ c:irua:160132 Serial 8457
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Author Asapu, R.; Claes, N.; Ciocarlan, R.-G.; Minjauw, M.; Detavernier, C.; Cool, P.; Bals, S.; Verbruggen, S.W.
Title Electron Transfer and Near-Field Mechanisms in Plasmonic Gold-Nanoparticle-Modified TiO2Photocatalytic Systems Type A1 Journal article
Year (down) 2019 Publication ACS applied nano materials Abbreviated Journal ACS Appl. Nano Mater.
Volume 2 Issue 2 Pages 4067-4074
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA); Sustainable Energy, Air and Water Technology (DuEL)
Abstract The major mechanism responsible for plasmonic enhancement of titanium dioxide photocatalysis using gold nanoparticles is still under contention. This work introduces an experimental strategy to disentangle the significance of the charge transfer and near-field mechanisms in plasmonic photocatalysis. By controlling the thickness and conductive nature of a nanoparticle shell that acts as a spacer layer separating the plasmonic metal core from the TiO2 surface, field enhancement or charge transfer effects can be selectively repressed or evoked. Layer-by-layer and in situ polymerization methods are used to synthesize gold core–polymer shell nanoparticles with shell thickness control up to the sub-nanometer level. Detailed optical and electrical characterization supported by near-field simulation models corroborate the trends in photocatalytic activity of the different systems. This approach mainly points at an important contribution of the enhanced near field.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000477917700006 Publication Date 2019-05-31
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2574-0970 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited 32 Open Access OpenAccess
Notes This work was supported by Research Foundation Flanders (FWO). P.C. and R-G.C. acknowledge financial support from FWO (Project No. G038215N). N.C. and S.B. acknowledge financial support from the European Research Council (ERC Starting Grant No. 335078-COLOURATOM). Approved Most recent IF: NA
Call Number EMAT @ emat @UA @ admin @ c:irua:160579 Serial 5184
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Author Crippa, F.; Rodriguez-Lorenzo, L.; Hua, X.; Goris, B.; Bals, S.; Garitaonandia, J.S.; Balog, S.; Burnand, D.; Hirt, A.M.; Haeni, L.; Lattuada, M.; Rothen-Rutishauser, B.; Petri-Fink, A.
Title Phase transformation of superparamagnetic iron oxide nanoparticles via thermal annealing : implications for hyperthermia applications Type A1 Journal article
Year (down) 2019 Publication ACS applied nano materials Abbreviated Journal
Volume 2 Issue 2 Pages 4462-4470
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract Magnetic hyperthermia has the potential to play an important role in cancer therapy and its efficacy relies on the nanomaterials selected. Superparamagnetic iron oxide nanoparticles (SPIONs) are excellent candidates due to the ability of producing enough heat to kill tumor cells by thermal ablation. However, their heating properties depend strongly on crystalline structure and size, which may not be controlled and tuned during the synthetic process; therefore, a postprocessing is needed. We show how thermal annealing can be simultaneously coupled with ligand exchange to stabilize the SPIONs in polar solvents and to modify their crystal structure, which improves hyperthermia behavior. Using high-resolution transmission electron microscopy, X-ray diffraction, Mossbauer spectroscopy, vibrating sample magnetometry, and lock-in thermography, we systematically investigate the impact of size and ligand exchange procedure on crystallinity, their magnetism, and heating ability. We describe a valid and simple approach to optimize SPIONs for hyperthermia by carefully controlling the size, colloidal stability, and crystallinity.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000477917700048 Publication Date 2019-06-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited 18 Open Access Not_Open_Access
Notes ; This work was supported by the Swiss National Science Foundation through the National Center of Competence in Research Bio-Inspired Materials, the Adolphe Merkle Foundation, the University of Fribourg, and the European Society for Molecular Imaging (Grant E141200643). ; Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:161927 Serial 5393
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Author Tang, Z.; Liu, P.; Cao, H.; Bals, S.; Heeres, H.J.; Pescarmona, P.P.
Title Pr/ZrO2 prepared by atomic trapping : an efficient catalyst for the conversion of glycerol to lactic acid with concomitant transfer hydrogenation of cyclohexene Type A1 Journal article
Year (down) 2019 Publication ACS catalysis Abbreviated Journal Acs Catal
Volume 9 Issue 9 Pages 9953-9963
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract A series of heterogeneous catalysts consisting of highly dispersed Pt nanoparticles supported on nanosized ZrO2 (20 to 60 nm) was synthesized and investigated for the one-pot transfer hydrogenation between glycerol and cyclohexene to produce lactic acid and cyclohexane, without any additional H-2. Different preparation methods were screened, by varying the calcination and reduction procedures with the purpose of optimizing the dispersion of Pt species (i.e., as single-atom sites or extra-fine Pt nanoparticles) on the ZrO2 support. The Pt/ZrO2 catalysts were characterized by means of transmission electron microscopy techniques (HAADF-STEM, TEM), elemental analysis (ICP-OES, EDX mapping), N-2-physisorption, H-2 temperature-programmed-reduction (H-2-TPR), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). Based on this combination of techniques it was possible to correlate the temperature of the calcination and reduction treatments with the nature of the Pt species. The best catalyst consisted of subnanometer Pt clusters (<1 nm) and atomically dispersed Pt (as Pt2+ and Pt4+) on the ZrO2 support, which were converted into extra-fine Pt nanoparticles (average size = 1.4 nm) upon reduction. These nanoparticles acted as catalytic species for the transfer hydrogenation of glycerol with cyclohexene, which gave an unsurpassed 95% yield of lactic acid salt at 96% glycerol conversion (aqueous glycerol solution, NaOH as promoter, 160 degrees C, 4.5 h, at 20 bar N-2). This is the highest yield and selectivity of lactic acid (salt) reported in the literature so far. Reusability experiments showed a partial and gradual loss of activity of the Pt/ZrO2 catalyst, which was attributed to the experimentally observed aggregation of Pt nanoparticles.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000494549700025 Publication Date 2019-09-16
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2155-5435 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 10.614 Times cited 46 Open Access OpenAccess
Notes Zhenchen Tang acknowledges the financial support from the China Scholarship Council for his Ph.D. grant. All the authors are grateful for the technical support from Erwin Wilbers, Anne Appeldoorn, and Marcel de Vries, the TEM support from Dr. Marc Stuart, and the ICP-OES support from Johannes van der Velde. Pei Liu and Sara Bals acknowledge financial support from the European Commission under the Horizon 2020 Programme by means of grant agreement No. 731019 EUSMI. Approved Most recent IF: 10.614
Call Number UA @ admin @ c:irua:164643 Serial 6326
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Author Gonzalez-Rubio, G.; Kumar, V.; Llombart, P.; Diaz-Nunez, P.; Bladt, E.; Altantzis, T.; Bals, S.; Pena-Rodriguez, O.; Noya, E.G.; MacDowell, L.G.; Guerrero-Martinez, A.; Liz-Marzan, L.M.
Title Disconnecting Symmetry Breaking from Seeded Growth for the Reproducible Synthesis of High Quality Gold Nanorods Type A1 Journal article
Year (down) 2019 Publication ACS nano Abbreviated Journal Acs Nano
Volume 13 Issue 13 Pages 4424-4435
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Applied Electrochemistry & Catalysis (ELCAT)
Abstract One of the major difficulties hindering the widespread application of colloidal anisotropic plasmonic nanoparticles is the limited robustness and reproducibility of multistep synthetic methods. We demonstrate herein that the reproducibility and reliability of colloidal gold nanorod (AuNR) synthesis can be greatly improved by disconnecting the symmetry-breaking event from the seeded growth process. We have used a modified silver-assisted seeded growth method in the presence of the surfactant hexadecyltrimethylammonium bromide and n-decanol as a co-surfactant to prepare small AuNRs in high yield, which were then used as seeds for the growth of high quality AuNR colloids. Whereas the use of n-decanol provides a more-rigid micellar system, the growth on anisotropic seeds avoids sources of irreproducibility during the symmetry breaking step, yielding uniform AuNR colloids with narrow plasmon bands, ranging from 600 to 1270 nm, and allowing the fine-tuning of the final dimensions. This method provides a robust route for the preparation of high quality AuNR colloids with tunable morphology, size, and optical response in a reproducible and scalable manner.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000466052900067 Publication Date 2019-04-02
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1936-0851 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 13.942 Times cited 100 Open Access OpenAccess
Notes ; This work has been funded by the Spanish MINECO (grant nos. FIS2017-89361-C3-2-P and MAT2017-86659-R), the Madrid Regional Government (grant no. P2018/NMT-4389) and the Complutense University of Madrid (grant no. PR75/18-21616). Funding is acknowledged from the European Commission (grant no. EUSMI 731019). G.G.-R. acknowledges receipt of FPI Fellowship from the Spanish MINECO. E.B. and T.A. acknowledge postdoctoral grants from the Research Foundation Flanders (FWO). The authors are indebted to Profs. Justin Gooding, Watson Loh, Nicholas Kotov, Deqing Zhang, Mihaela Delcea, Maurizio Prato, and Krishna Ganesh, for providing milli-Q water samples. ; Approved Most recent IF: 13.942
Call Number UA @ admin @ c:irua:160417 Serial 5246
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Author Jishkariani, D.; Elbert, K.C.; Wu, Y.; Lee, J.D.; Hermes, M.; Wang, D.; van Blaaderen, A.; Murray, C.B.
Title Nanocrystal Core Size and Shape Substitutional Doping and Underlying Crystalline Order in Nanocrystal Superlattices Type A1 Journal article
Year (down) 2019 Publication ACS nano Abbreviated Journal Acs Nano
Volume 13 Issue 5 Pages 5712-5719
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract Substitutional doping is a potentially powerful technique to control the properties of nanocrystal (NC) superlattices (SLs). However, not every NC can be substituted into any lattice, as the NCs have to be close in size and shape, limiting the application of substitutional doping. Here we show that this limitation can be overcome by employing ligands of various size. We show that small NCs with long ligands can be substituted into SLs of big NCs with short ligands. Furthermore, we show that shape differences can also be overcome and that cubes can substitute spheres when both are coated with long ligands. Finally, we use the NC effective ligand size, softness, and effective overall size ratio to explain observed doping behaviors.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000469886300078 Publication Date 2019-05-03
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1936-0851 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 13.942 Times cited 6 Open Access Not_Open_Access
Notes ; This work was supported by the University of Pennsylvania's NSF MRSEC under award no. DMR-112090 and the CNRS-UPENN-SOLVAY through the Complex Assemblies of Soft Matter Laboratory (COMPASS). K.C.E. acknowledges support from the NSF Graduate Research Fellowship Program under grant no. DGE-1321851. C.B.M. acknowledges the Richard Perry University Professorship at the University of Pennsylvania. D.W. and A.v.B. acknowledge partial funding from the European Research Council under the European Union's Seventh Framework Programme (FP -2007-2013)/ERC Advanced Grant Agreement 291667 HierarSACol. M.H. was supported by The Netherlands Center for Multiscale Catalytic Energy Conversion (MCEC), an NWO Gravitation programme funded by the Ministry of Education, Culture and Science of the government of The Netherlands. The authors thank EM square in Utrecht University for the access to the microscopes. ; Approved Most recent IF: 13.942
Call Number UA @ admin @ c:irua:160344 Serial 5256
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Author Albrecht, W.; Bladt, E.; Vanrompay, H.; Smith, J.D.; Skrabalak, S.E.; Bals, S.
Title Thermal Stability of Gold/Palladium Octopods Studied in Situ in 3D: Understanding Design Rules for Thermally Stable Metal Nanoparticles Type A1 Journal article
Year (down) 2019 Publication ACS nano Abbreviated Journal Acs Nano
Volume 13 Issue 13 Pages 6522-6530
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract Multifunctional metal nanoparticles (NPs) such as anisotropic multimetallic NPs are crucial for boosting nanomaterial based applications. Advanced synthetic protocols exist to make a large variety of such nanostructures. However, a major limiting factor for the usability of them in real life applications is their stability. Here, we show that Au/Pd octopods, 8-branched nanocrystals with Oh symmetry, with only a low amount of Pd exhibited a high thermal stability and maintained strong plasmon resonances up to 600 ◦C. Furthermore, we study the influence of the composition, morphology and environment on the thermal stability and define key parameters for the design of thermally stable multifunctional NPs.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000473248300038 Publication Date 2019-06-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1936-0851 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 13.942 Times cited 46 Open Access OpenAccess
Notes W. A. acknowledges an Individual Fellowship funded by the Marie Sklodowska-Curie Actions (MSCA) in Horizon 2020. H. V. acknowledges financial support by the Research Foundation Flanders (FWO grant 1S32617N). E. B. acknowledges a post-doctoral grant from the Research Foundation Flanders (FWO, Belgium). J. D. S. and S.E.S acknowledge funding from the US National Science Foundation (award number: CHE-1602476). The authors acknowledge funding from the European Commission Grant (EUSMI E180600101 to S. B. and S. E. S.) and European Research Council (ERC Starting Grant #335078-COLOURATOMS). Realnano 815128; sygma Approved Most recent IF: 13.942
Call Number EMAT @ emat @c:irua:161356 Serial 5285
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Author Skorikov, A.; Albrecht, W.; Bladt, E.; Xie, X.; van der Hoeven, J.E.S.; van Blaaderen, A.; Van Aert, S.; Bals, S.
Title Quantitative 3D Characterization of Elemental Diffusion Dynamics in Individual Ag@Au Nanoparticles with Different Shapes Type A1 Journal article
Year (down) 2019 Publication ACS nano Abbreviated Journal Acs Nano
Volume 13 Issue 13 Pages 13421-13429
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract Anisotropic bimetallic nanoparticles are promising candidates for plasmonic and catalytic applications. Their catalytic performance and plasmonic properties are closely linked to the distribution of the two metals, which can change during applications in which the particles are exposed to heat. Due to this fact, correlating the thermal stability of complex heterogeneous nanoparticles to their microstructural properties is of high interest for the practical applications of such materials. Here, we employ quantitative electron tomography in high-angle annular dark-field scanning transmission electron microscopy (HAADFSTEM) mode to measure the 3D elemental diffusion dynamics in individual anisotropic Au−Ag nanoparticles upon heating in situ. This approach allows us to study the elemental redistribution in complex, asymmetric nanoparticles on a single particle level, which has been inaccessible to other techniques so far. In this work, we apply the proposed method to compare the alloying dynamics of Au−Ag nanoparticles with different shapes and compositions and find that the shape of the nanoparticle does not exhibit a significant effect on the alloying speed whereas the composition does. Finally, comparing the experimental results to diffusion simulations allows us to estimate the diffusion coefficients of the metals for individual nanoparticles.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000500650000115 Publication Date 2019-10-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1936-0851 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 13.942 Times cited 29 Open Access OpenAccess
Notes This project has received funding from the European Commission (grant 731019, EUSMI) and European Research Council (ERC Consolidator Grants 815128, REALNANO; 770887, PICOMETRICS; 648991, 3MC; and ERC Advanced Grant 291667, HierarSACol). This project has also received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement 823717, ESTEEM3. W.A. acknowledges an Individual Fellowship funded by the Marie Sklodowska-Curie Actions (MSCA) in Horizon 2020 program (grant 797153, SOPMEN). E.B. acknowledges a postdoctoral grant 12T2719N from the Research Foundation Flanders (FWO, Belgium). X.X. acknowledges financial support from the EU H2020-MSCAITN-2015 project 676045, MULTIMAT. The authors also acknowledge financial support by the Research Foundation Flanders (FWO grants G038116N, G026718N, and G036915N).; sygma; esteem3JRA; esteem3reported Approved Most recent IF: 13.942
Call Number EMAT @ emat @c:irua:164061 Serial 5379
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Author Hinterding, S.O.M.; Berends, A.C.; Kurttepeli, M.; Moret, M.-E.; Meeldijk, J.D.; Bals, S.; van der Stam, W.; de Donega, C.M.
Title Tailoring Cu+ for Ga3+ cation exchange in Cu2-xS and CuInS2 nanocrystals by controlling the Ga precursor chemistry Type A1 Journal article
Year (down) 2019 Publication ACS nano Abbreviated Journal Acs Nano
Volume 13 Issue 13 Pages 12880-12893
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract Nanoscale cation exchange (CE) has resulted in colloidal nanomaterials that are unattainable by direct synthesis methods. Aliovalent CE is complex and synthetically challenging because the exchange of an unequal number of host and guest cations is required to maintain charge balance. An approach to control aliovalent CE reactions is the use of a single reactant to both supply the guest cation and extract the host cation. Here, we study the application of GaCl3-L complexes [L = trioctylphosphine (TOP), triphenylphosphite (TPP), diphenylphosphine (DPP)] as reactants in the exchange of Cu+ for Ga3+ in Cu2-xS nanocrystals. We find that noncomplexed GaCl3 etches the nanocrystals by S2- extraction, whereas GaCl3-TOP is unreactive. Successful exchange of Cu+ for Ga3+ is only possible when GaCl3 is complexed with either TPP or DPP. This is attributed to the pivotal role of the Cu2-xS-GaCl3-L activated complex that forms at the surface of the nanocrystal at the onset of the CE reaction, which must be such that simultaneous Ga3+ insertion and Cu+ extraction can occur. This requisite is only met if GaCl3 is bound to a phosphine ligand, with a moderate bond strength, to allow facile dissociation of the complex at the nanocrystal surface. The general validity of this mechanism is demonstrated by using GaCl3-DPP to convert CuInS2 into (Cu,Ga,In)S-2 nanocrystals, which increases the photoluminescence quantum yield 10 -fold, while blue -shifting the photoluminescence into the NIR biological window. This highlights the general applicability of the mechanistic insights provided by our work.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000500650000061 Publication Date 2019-10-16
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1936-0851 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 13.942 Times cited 27 Open Access OpenAccess
Notes ; S.O.M.H., W.v.d.S., A.C.B., and C.d.M.D. acknowledge financial support from the division of Chemical Sciences (CW) of The Netherlands Organization for Scientific Research (NWO) under Grant Nos. ECHO.712.012.0001 and ECHO.712.014.001. S.B. acknowledges financial support from the European Research Council (ERC Consolidator Grant No. 815128-REALNANO). S.O.M.H. is supported by The Netherlands Center for Multiscale Catalytic Energy Conversion (MCEC), an NWO Gravitation Programme funded by the Ministry of Education, Culture and Science of the government of The Netherlands. DFT calculations were carried out on the Dutch national e-infrastructure with the support of SURF Cooperative. This work was sponsored by NWO Physical Sciences for the use of supercomputer facilities. The authors thank Jessi van der Hoeven for EDS and TEM measurements. ; sygma Approved Most recent IF: 13.942
Call Number UA @ admin @ c:irua:165149 Serial 6324
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