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Author (down) Van 't dack, L.; Beusen, J.-M.; Claesson, T.; Vandelannoote, R.; van Grieken, R.; Gijbels, R.
Title Experimental weathering studies of igneous rocks (alkali-granite, granodiorite, gabbro and granite) and sedimentary gneiss under hydrothermal conditions Type P3 Proceeding
Year 1985 Publication Abbreviated Journal
Volume Issue Pages 363-368
Keywords P3 Proceeding; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT); AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication S.l. Editor
Language Wos Publication Date 0000-00-00
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Additional Links UA library record
Impact Factor Times cited Open Access
Notes Approved
Call Number UA @ lucian @ c:irua:111512 Serial 1146
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Author (down) Vallius, M.; Janssen, N.A.H.; Heinrich, J.; Hoek, G.; Ruuskanen, J.; Cyrys, J.; Van Grieken, R.; de Hartog, J.J.; Kreyling, W.G.; Pekkanen, J.
Title Sources and elemental composition of ambient PM2.5 in three European cities Type A1 Journal article
Year 2005 Publication The science of the total environment Abbreviated Journal
Volume 337 Issue Pages 147-162
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000226661700013 Publication Date 2004-08-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0048-9697; 1879-1026 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:49804 Serial 8560
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Author (down) Vallicrosa, H.; Lugli, L.F.; Fuchslueger, L.; Sardans, J.; Ramirez-Rojas, I.; Verbruggen, E.; Grau, O.; Brechet, L.; Peguero, G.; Van Langenhove, L.; Verryckt, L.T.; Terrer, C.; Llusia, J.; Ogaya, R.; Marquez, L.; Roc-Fernandez, P.; Janssens, I.; Penuelas, J.
Title Phosphorus scarcity contributes to nitrogen limitation in lowland tropical rainforests Type A1 Journal article
Year 2023 Publication Ecology Abbreviated Journal
Volume 104 Issue 6 Pages e4049-12
Keywords A1 Journal article; Plant and Ecosystems (PLECO) – Ecology in a time of change
Abstract There is increasing evidence to suggest that soil nutrient availability can limit the carbon sink capacity of forests, a particularly relevant issue considering today's changing climate. This question is especially important in the tropics, where most part of the Earth's plant biomass is stored. To assess whether tropical forest growth is limited by soil nutrients and to explore N and P limitations, we analyzed stem growth and foliar elemental composition of the five stem widest trees per plot at two sites in French Guiana after 3 years of nitrogen (N), phosphorus (P), and N + P addition. We also compared the results between potential N-fixer and non-N-fixer species. We found a positive effect of N fertilization on stem growth and foliar N, as well as a positive effect of P fertilization on stem growth, foliar N, and foliar P. Potential N-fixing species had greater stem growth, greater foliar N, and greater foliar P concentrations than non-N-fixers. In terms of growth, there was a negative interaction between N-fixer status, N + P, and P fertilization, but no interaction with N fertilization. Because N-fixing plants do not show to be completely N saturated, we do not anticipate N providing from N-fixing plants would supply non-N-fixers. Although the soil-age hypothesis only anticipates P limitation in highly weathered systems, our results for stem growth and foliar elemental composition indicate the existence of considerable N and P co-limitation, which is alleviated in N-fixing plants. The evidence suggests that certain mechanisms invest in N to obtain the scarce P through soil phosphatases, which potentially contributes to the N limitation detected by this study.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000977760600001 Publication Date 2023-04-11
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0012-9658; 1939-9170 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:196804 Serial 9218
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Author (down) Valkering, A.M.C.; Sommerfeld, P.K.H.; van de Ven, R.A.M.; van der Heijden, R.W.; Blom, F.A.P.; Lea, M.J.; Peeters, F.M.
Title Hall magnetocapitance in two-dimensional electron systems Type A1 Journal article
Year 1998 Publication Physical review letters Abbreviated Journal Phys Rev Lett
Volume 81 Issue Pages 5398-5401
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication New York, N.Y. Editor
Language Wos 000077511700036 Publication Date 2002-07-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0031-9007;1079-7114; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 8.462 Times cited 4 Open Access
Notes Approved Most recent IF: 8.462; 1998 IF: 6.017
Call Number UA @ lucian @ c:irua:24153 Serial 1402
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Author (down) Vaitkeviciute, J.; Chakir, R.; Van Passel, S.
Title Climate variable choice in Ricardian studies of European Agriculture Type A1 Journal article
Year 2019 Publication Revue économique Abbreviated Journal
Volume 70 Issue 3 Pages 375-401
Keywords A1 Journal article; Economics; Engineering Management (ENM)
Abstract The Ricardian model has been employed frequently to study the impact of climate change on European agriculture. This paper contributes to this literature by using a panel data of FADN EU regions and the period 2004-2012 and by taking into account both individual heterogeneity as well as spatial autocorrelation among EU regions. We tested three hypotheses related to the degree days model. Our results show that climate outside the defined growing season matters for European agriculture, and excluding it could underestimate climate change impacts. Our results should support public policy decisions about efficient and effective mitigation and adaptation policy measures in EU agriculture.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000469914100005 Publication Date 2019-05-23
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0035-2764; 1950-6694 ISBN Additional Links UA library record; WoS full record
Impact Factor Times cited Open Access
Notes ; We thank the two anonymous referees and the editors of the Revue economique for their useful comments which have helped us to improve the paper significantly. The usual disclaimers apply. The research leading to these results received funding from the European Union within the European Commission Seventh Framework Programme in the frame of RURAGRI ERA-NET under Grant Agreement 235175 TRUSTEE (ANR-13-RURA-0001-01) and from the Agence Nationale de la Recherche within STIMUL (Scenarios Towards integrating multi-scale land use tools) flagship project as part of the “Investissements d'Avenir” Programme (LabEx BASC; ANR-11-LABX-0034). This work was also supported by the metaprogramme Adaptation of Agriculture and Forest to Climate Change (AAFCC) of the French National Institute for Agricultural Research (INRA). Neither the French Agence Nationale de la Recherche nor the European Union or European Commission organization is accountable for the content of this research. The authors are solely responsible for any omissions or deficiencies. ; Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:160346 Serial 6167
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Author (down) Vagov, A.V.; Shanenko, A.A.; Milošević, M.V.; Axt, V.M.; Peeters, F.M.
Title Extended Ginzburg-Landau formalism : systematic expansion in small deviation from the critical temperature Type A1 Journal article
Year 2012 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 85 Issue 1 Pages 014502-014502,17
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Based on the Gor'kov formalism for a clean s-wave superconductor, we develop an extended version of the single-band Ginzburg-Landau (GL) theory by means of a systematic expansion in the deviation from the critical temperature T(c), i.e., tau = 1 – T/T(c). We calculate different contributions to the order parameter and the magnetic field: the leading contributions (proportional to tau(1/2) in the order parameter and. t in the magnetic field) are controlled by the standard GL theory, while the next-to-leading terms (proportional to tau(3/2) in the gap and proportional to tau(2) in the magnetic field) constitute the extended GL (EGL) approach. We derive the free-energy functional for the extended formalism and the corresponding expression for the current density. To illustrate the usefulness of our formalism, we calculate, in a semianalytical form, the temperature-dependent correction to the GL parameter at which the surface energy becomes zero, and analytically, the temperature dependence of the thermodynamic critical field. We demonstrate that the EGL formalism is not just a mathematical extension to the theory: variations of both the gap and the thermodynamic critical field with temperature calculated within the EGL theory are found in very good agreement with the full BCS results down to low temperatures, which dramatically improves the applicability of the formalism compared to its standard predecessor.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000298985100002 Publication Date 2012-01-10
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 36 Open Access
Notes ; This work was supported by the Flemish Science Foundation (FWO-Vl) and the Belgian Science Policy (IAP). A. V. V. is grateful to V. Zalipaev for important comments. A. A. S. thanks W. Pogosov for helpful notes. Discussions with E. H. Brandt and A. Perali are appreciated. ; Approved Most recent IF: 3.836; 2012 IF: 3.767
Call Number UA @ lucian @ c:irua:96232 Serial 1155
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Author (down) Vagov, A.; Shanenko, A.A.; Milošević, M.V.; Axt, V.M.; Vinokur, V.M.; Aguiar, J.A.; Peeters, F.M.
Title Superconductivity between standard types: Multiband versus single-band materials Type A1 Journal article
Year 2016 Publication Physical review B Abbreviated Journal Phys Rev B
Volume 93 Issue 93 Pages 174503
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000375527500001 Publication Date 2016-05-06
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 37 Open Access
Notes Conselho Nacional de Desenvolvimento Científico e Tecnológico, 307552/2012-8 141911/2012-3 ; Fundação de Amparo à Ciência e Tecnologia do Estado de Pernambuco, APQ-0589-1.05/08 ; U.S. Department of Energy; Approved Most recent IF: 3.836
Call Number CMT @ cmt @ c:irua:141732 Serial 4480
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Author (down) Vagov, A.; Shanenko, A.A.; Milošević, M.V.; Axt, V.M.; Peeters, F.M.
Title Two-band superconductors : extended Ginzburg-Landau formalism by a systematic expansion in small deviation from the critical temperature Type A1 Journal article
Year 2012 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 86 Issue 14 Pages 144514
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We derive the extended Ginzburg-Landau (GL) formalism for a clean s-wave two-band superconductor by employing a systematic expansion of the free-energy functional and the corresponding matrix gap equation in powers of the small deviation from the critical temperature tau = 1 – T/T-c. The two lowest orders of this expansion produce the equation for T-c and the standard GL theory. It is shown that in agreement with previous studies, this two-band GL theory maps onto the single-band GL model and thus fails to describe the difference in the spatial profiles of the two-band condensates. We prove that this difference appears already in the leading correction to the standard GL theory, which constitutes the extended GL formalism. We derive linear differential equations that determine the leading corrections to the band order parameters and magnetic field, discuss the validity of these equations, and consider examples of an important interplay between the band condensates. Finally, we present numerical results for the thermodynamic critical magnetic field and temperature-dependent band gaps for recent materials of interest, which are in very good agreement with those obtained from the full BCS approach in a wide temperature range. To this end, we emphasize the advantages of our extended GL theory in comparison with the often used two-component GL-like model based on an unreconstructed two-band generalization of the Gor'kov derivation.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000309776800001 Publication Date 2012-10-12
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 44 Open Access
Notes ; This work was supported by the Flemish Science Foundation (FWO-Vl). Authors are indebted to Y. Singh and R. Prozorov for discussions and for providing recent experimental data. A. V. is grateful to W. Pesch for stimulating discussions and critical comments on this work. ; Approved Most recent IF: 3.836; 2012 IF: 3.767
Call Number UA @ lucian @ c:irua:101798 Serial 3769
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Author (down) Vagov, A.; Schomerus, H.; Shanenko, A.
Title Generalized Galitskii approach for the vertex function of a Fermi gas with resonant interaction Type A1 Journal article
Year 2007 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 76 Issue 21 Pages 214513-214517
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We present a generalized Galitskii approach for the Bethe-Salpeter equation for the two-particle vertex function of a Fermi system with the resonant interaction by accounting for the resonant state in the scattering potential and utilizing the universal form of the resonant scattering amplitude. The procedure can be carried out both for the normal as well as for the condensate state. In both cases, the vertex function in the vicinity of the resonance is shown to formally coincide with that obtained for a weakly attractive Fermi gas. Thus we justify the popular calculational framework in which results for the weakly attractive Fermi gas are formally extrapolated into the domain of strong coupling, and further to the repulsive side of the resonance, where molecular states are formed.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000251986100097 Publication Date 2007-12-28
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 8 Open Access
Notes Approved Most recent IF: 3.836; 2007 IF: 3.172
Call Number UA @ lucian @ c:irua:104037 Serial 1324
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Author (down) Vagov, A.; Glaessl, M.; Croitoru, M.D.; Axt, V.M.; Kuhn, T.
Title Competition between pure dephasing and photon losses in the dynamics of a dot-cavity system Type A1 Journal article
Year 2014 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 90 Issue 7 Pages 075309
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We demonstrate that in quantum-dot cavity systems, the interplay between acoustic phonons and photon losses introduces novel features and characteristic dependencies in the system dynamics. In particular, the combined action of both dephasing mechanisms strongly affects the transition from the weak-to the strong-coupling regime as well as the shape of the spectral triplet that represents the quantum-dot occupation in Fourier space. The width of the central peak in the triplet is expected to decrease with rising temperature, while the widths and heights of the side peaks depend nonmonotonically on the dot-cavity coupling.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000341258700002 Publication Date 2014-08-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 11 Open Access
Notes ; We acknowledge fruitful discussions with A. Nazir which helped us to more clearly formulate the relation between our phenomenological approach and the microscopic theory. M.D.C. further acknowledges Alexander von Humboldt and BELSPO grants for support. Financial support from the Deutsche Forschungsgemeinschaft (Grant No. AX 17/7-1) is also gratefully acknowledged. ; Approved Most recent IF: 3.836; 2014 IF: 3.736
Call Number UA @ lucian @ c:irua:119257 Serial 437
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Author (down) Vagov, A.; Croitoru, M.D.; Axt, V.M.; Kuhn, T.; Peeters, F.M.
Title High pulse area undamping of Rabi oscillations in quantum dots coupled to phonons Type A1 Journal article
Year 2006 Publication Physica status solidi B – Basic solid state physics Abbreviated Journal Phys Status Solidi B
Volume 243 Issue 10 Pages 2233-2240
Keywords A1 Journal article; Condensed Matter Theory (CMT); Electron microscopy for materials research (EMAT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000239932300005 Publication Date 2006-07-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0370-1972;1521-3951; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.674 Times cited 16 Open Access
Notes Approved Most recent IF: 1.674; 2006 IF: 0.967
Call Number UA @ lucian @ c:irua:60891 Serial 1440
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Author (down) Vagov, A.; Croitoru, M.D.; Axt, V.M.; Kuhn, T.; Peeters, F.M.
Title Nonmonotonic field dependence of damping and reappearance of Rabi oscillations in quantum dots Type A1 Journal article
Year 2007 Publication Physical review letters Abbreviated Journal Phys Rev Lett
Volume 98 Issue 22 Pages 1-4
Keywords A1 Journal article; Condensed Matter Theory (CMT); Electron microscopy for materials research (EMAT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication New York, N.Y. Editor
Language Wos 000246910100059 Publication Date 2007-06-01
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0031-9007;1079-7114; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 8.462 Times cited 91 Open Access
Notes Iap Approved Most recent IF: 8.462; 2007 IF: 6.944
Call Number UA @ lucian @ c:irua:64768 Serial 2362
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Author (down) Vagov, A.; Croitoru, M.D.; Axt, V.M.; Kuhn, T.; Peeters, F.
Title Real time path integrals in studies of quantum dots dynamics: non-monotonous decay rate and reappearance of rabi rotations Type P1 Proceeding
Year 2008 Publication Path Integrals : New Trends and Perspectives, Proceedings Abbreviated Journal
Volume Issue Pages 57-62
Keywords P1 Proceeding; Condensed Matter Theory (CMT)
Abstract The dynamics of strongly confined laser driven semiconductor quantum dots coupled to phonons is studied theoretically by calculating the time evolution of the reduced density matrix using the path integral method. We explore the cases of long pulses, strong dot-phonon and dot-laser coupling and high temperatures, which up to now have been inaccessible. We find that the decay rate of the Rabi oscillations is a non-monotonic function of the laser field leading to the decay and reappearance of the Rabi oscillations in the field dependence of the dot exciton population.
Address
Corporate Author Thesis
Publisher World Scientific Place of Publication Singapore Editor
Language Wos 000264341000007 Publication Date 2009-09-15
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Additional Links UA library record; WoS full record
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ lucian @ c:irua:95702 Serial 2834
Permanent link to this record
 

 
Author (down) Vagin, M.Y.; Trashin, S.A.; Beloglazkina, E.K.; Majouga, A.G.
Title Direct reagentless detection of the affinity binding of recombinant His-tagged firefly luciferase with a nickel-modified gold electrode Type A1 Journal article
Year 2015 Publication Mendeleev communications Abbreviated Journal
Volume 25 Issue 4 Pages 290-292
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract The direct reagentless electrochemical detection of recombinant firefly luciferase binding with a gold electrode modified with nickel complex of 1,16-di[4-(2,6-dihydroxycarbonyl)pyridyl]-1,16-dioxa-8,9-dithiahexadecane has been carried out.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000360416600021 Publication Date 2015-08-07
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0959-9436 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:127814 Serial 7811
Permanent link to this record
 

 
Author (down) Uzonyi, I.; Szöör, G.; Vekemans, B.; Vincze, L.; Rozsa, P.; Szabo, G.; Somogyi, A.; Adams, F.; Kiss, Á.Z.
Title Application of combined micro-proton-induced X-ray emission and micro-synchrotron radiation X-ray fluorescence techniques for the characterization of impact materials around Barringer Meteor Crater Type A1 Journal article
Year 2004 Publication Spectrochimica acta: part B : atomic spectroscopy Abbreviated Journal
Volume 59 Issue Pages 1717-1723
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000224848000031 Publication Date 2004-09-14
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0584-8547; 1873-3565 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:49638 Serial 7469
Permanent link to this record
 

 
Author (down) Uzonyi, I.; Szöör, G.; Rozsa, P.; Vekemans, B.; Vincze, L.; Adams, F.; Drakopoulos, M.; Somogyi, A.; Kiss, Á.Z.
Title Characterization of impact materials around Barringer meteor crater by micro-PIXE nd micro-SRXRF techniques Type A1 Journal article
Year 2004 Publication Nuclear instruments and methods in physics research: B: beam interactions with materials and atoms Abbreviated Journal
Volume 219/220 Issue Pages 555-560
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000221895800104 Publication Date 2004-02-21
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0168-583x 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:46507 Serial 7622
Permanent link to this record
 

 
Author (down) Uytdenhouwen, Y.; Van Alphen, S.; Michielsen, I.; Meynen, V.; Cool, P.; Bogaerts, A.
Title A packed-bed DBD micro plasma reactor for CO 2 dissociation: Does size matter? Type A1 Journal article
Year 2018 Publication Chemical engineering journal Abbreviated Journal Chem Eng J
Volume 348 Issue Pages 557-568
Keywords A1 Journal article; Laboratory of adsorption and catalysis (LADCA); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract DBD plasma reactors are of great interest for environmental and energy applications, such as CO2 conversion, but they suffer from limited conversion and especially energy efficiency. The introduction of packing materials has been a popular subject of investigation in order to increase the reactor performance. Reducing the discharge gap of the reactor below one millimetre can enhance the plasma performance as well. In this work, we combine both effects and use a packed-bed DBD micro plasma reactor to investigate the influence of gap size reduction, in combination with a packing material, on the conversion and efficiency of CO2 dissociation. Packing materials used in this work were SiO2, ZrO2, and Al2O3 spheres as well as glass wool. The results are compared to a regular size reactor as a benchmark. Reducing the discharge gap can greatly increase the CO2 conversion, although at a lower energy efficiency. Adding a packing material further increases the conversion when keeping a constant residence time, but is greatly dependent on the material composition, gap and sphere size used. Maximum conversions of 50–55% are obtained for very long residence times (30 s and higher) in an empty reactor or with certain packing material combinations, suggesting a balance in CO2 dissociation and recombination reactions. The maximum energy efficiency achieved is 4.3%, but this is for the regular sized reactor at a short residence time (7.5 s). Electrical characterization is performed to reveal some trends in the electrical behaviour of the plasma upon reduction of the discharge gap and addition of a packing material.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000434467000055 Publication Date 2018-05-03
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1385-8947 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.216 Times cited 22 Open Access Not_Open_Access: Available from 03.05.2020
Notes We acknowledge financial support from the European Fund for Regional Development through the cross-border collaborative Interreg V program Flanders-the Netherlands (project EnOp), the Fund for Scientific Research (FWO; Grant Number: G.0254.14N) and an IOF-SBO (SynCO2Chem) project from the University of Antwerp. Approved Most recent IF: 6.216
Call Number PLASMANT @ plasmant @c:irua:151238 Serial 4956
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Author (down) Uytdenhouwen, Y.; Meynen, V.; Cool, P.; Bogaerts, A.
Title The Potential Use of Core-Shell Structured Spheres in a Packed-Bed DBD Plasma Reactor for CO2 Conversion Type A1 Journal article
Year 2020 Publication Catalysts Abbreviated Journal Catalysts
Volume 10 Issue 5 Pages 530
Keywords A1 Journal article; Laboratory of adsorption and catalysis (LADCA); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract This work proposes to use core-shell structured spheres to evaluate whether it allows to individually optimize bulk and surface effects of a packing material, in order to optimize conversion and energy efficiency. Different core-shell materials have been prepared by spray coating, using dense spheres (as core) and powders (as shell) of SiO2, Al2O3, and BaTiO3. The materials are investigated for their performance in CO2 dissociation and compared against a benchmark consisting of a packed-bed reactor with the pure dense spheres, as well as an empty reactor. The results in terms of CO2 conversion and energy efficiency show various interactions between the core and shell material, depending on their combination. Al2O3 was found as the best core material under the applied conditions here, followed by BaTiO3 and SiO2, in agreement with their behaviour for the pure spheres. Applying a thin shell layer on the cores showed equal performance between the different shell materials. Increasing the layer thickness shifts this behaviour, and strong combination effects were observed depending on the specific material. Therefore, this method of core-shell spheres has the potential to allow tuning of the packing properties more closely to the application by designing an optimal combination of core and shell.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000546007000092 Publication Date 2020-05-11
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2073-4344 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.9 Times cited Open Access
Notes Interreg, Project EnOp ; Fonds Wetenschappelijk Onderzoek, G.0254.14N ; Universiteit Antwerpen, Project SynCO2Chem ; We want to thank Jasper Lefevre (VITO) for assistance in the development of the coating suspension for the core-shell spheres. Approved Most recent IF: 3.9; 2020 IF: 3.082
Call Number PLASMANT @ plasmant @c:irua:169222 Serial 6364
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Author (down) Uytdenhouwen, Y.; Hereijgers, J.; Breugelmans, T.; Cool, P.; Bogaerts, A.
Title How gas flow design can influence the performance of a DBD plasma reactor for dry reforming of methane Type A1 Journal article
Year 2021 Publication Chemical Engineering Journal Abbreviated Journal Chem Eng J
Volume 405 Issue Pages 126618
Keywords A1 Journal article; Engineering sciences. Technology; Laboratory of adsorption and catalysis (LADCA); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT); Applied Electrochemistry & Catalysis (ELCAT)
Abstract DBD plasma reactors are commonly used in a static ‘one inlet – one outlet’ design that goes against reactor design principles for multi-component reactions, such as dry reforming of methane (DRM). Therefore, in this paper we have developed a novel reactor design, and investigated how the shape and size of the reaction zone, as well as gradual gas addition, and the method of mixing CO2 and CH4 can influence the conversion and product com­ position of DRM. Even in the standard ‘one inlet – one outlet’ design, the direction of the gas flow (i.e. short or long path through the reactor, which defines the gas velocity at fixed residence time), as well as the dimensions of the reaction zone and the power delivery to the reactor, largely affect the performance. Using gradual gas addition and separate plasma activation zones for the individual gases give increased conversions within the same operational parameters, by optimising mixing ratios and kinetics. The choice of the main (pre-activated) gas and the direction of gas flow largely affect the conversion and energy cost, while the gas inlet position during separate addition only influences the product distribution.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000626511800005 Publication Date 2020-08-12
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1385-8947 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.216 Times cited Open Access OpenAccess
Notes Interreg; Flanders; FWO; University of Antwerp; The authors acknowledge financial support from the European Fund for Regional Development through the cross-border collaborative Interreg V program Flanders-the Netherlands (project EnOp), the Fund 13 for Scientific Research (FWO; grant number: G.0254.14N), and an IOFSBO (SynCO2Chem) project from the University of Antwerp. Approved Most recent IF: 6.216
Call Number PLASMANT @ plasmant @c:irua:170609 Serial 6410
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Author (down) Uytdenhouwen, Y.; Bal, Km.; Neyts, Ec.; Meynen, V.; Cool, P.; Bogaerts, A.
Title On the kinetics and equilibria of plasma-based dry reforming of methane Type A1 Journal article
Year 2021 Publication Chemical Engineering Journal Abbreviated Journal Chem Eng J
Volume 405 Issue Pages 126630
Keywords A1 Journal article; Laboratory of adsorption and catalysis (LADCA); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Plasma reactors are interesting for gas-based chemical conversion but the fundamental relation between the plasma chemistry and selected conditions remains poorly understood. Apparent kinetic parameters for the loss and formation processes of individual components of gas conversion processes, can however be extracted by performing experiments in an extended residence time range (2–75 s) and fitting the gas composition to a firstorder kinetic model of the evolution towards partial chemical equilibrium (PCE). We specifically investigated the differences in kinetic characteristics and PCE state of the CO2 dissociation and CH4 reforming reactions in a dielectric barrier discharge reactor (DBD), how these are mutually affected when combining both gases in the dry reforming of methane (DRM) reaction, and how they change when a packing material (non-porous SiO2) is added to the reactor. We find that CO2 dissociation is characterized by a comparatively high reaction rate of 0.120 s−1 compared to CH4 reforming at 0.041 s−1; whereas CH4 reforming reaches higher equilibrium conversions, 82% compared to 53.6% for CO2 dissociation. Combining both feed gases makes the DRM reaction to proceed at a relatively high rate (0.088 s−1), and high conversion (75.4%) compared to CO2 dissociation, through accessing new chemical pathways between the products of CO2 and CH4. The addition of the packing material can also distinctly influence the conversion rate and position of the equilibrium, but its precise effect depends strongly on the gas composition. Comparing different CO2:CH4 ratios reveals the delicate balance of the combined chemistry. CO2 drives the loss reactions in DRM, whereas CH4 in the mixture suppresses back reactions. As a result, our methodology provides some of the insight necessary to systematically tune the conversion process.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000621197700003 Publication Date 2020-08-12
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1385-8947 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.216 Times cited Open Access OpenAccess
Notes The authors acknowledge financial support from the European Fund for Regional Development through the cross-border collaborative Interreg V program Flanders-the Netherlands (project EnOp), the Fund for Scientific Research (FWO; grant number: G.0254.14N), a TOP-BOF project and an IOF-SBO (SynCO2Chem) project from the University of Antwerp. Approved Most recent IF: 6.216
Call Number PLASMANT @ plasmant @c:irua:172458 Serial 6411
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Author (down) Uytdenhouwen, Y.; Bal, Km.; Michielsen, I.; Neyts, Ec.; Meynen, V.; Cool, P.; Bogaerts, A.
Title How process parameters and packing materials tune chemical equilibrium and kinetics in plasma-based CO2 conversion Type A1 Journal article
Year 2019 Publication Chemical engineering journal Abbreviated Journal Chem Eng J
Volume 372 Issue Pages 1253-1264
Keywords A1 Journal article; Laboratory of adsorption and catalysis (LADCA); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Plasma (catalysis) reactors are increasingly being used for gas-based chemical conversions, providing an alternative method of energy delivery to the molecules. In this work we explore whether classical concepts such as

equilibrium constants, (overall) rate coefficients, and catalysis exist under plasma conditions. We specifically

investigate the existence of a so-called partial chemical equilibrium (PCE), and how process parameters and

packing properties influence this equilibrium, as well as the overall apparent rate coefficient, for CO2 splitting in

a DBD plasma reactor. The results show that a PCE can be reached, and that the position of the equilibrium, in

combination with the rate coefficient, greatly depends on the reactor parameters and operating conditions (i.e.,

power, pressure, and gap size). A higher power, higher pressure, or smaller gap size enhance both the equilibrium constant and the rate coefficient, although they cannot be independently tuned. Inserting a packing

material (non-porous SiO2 and ZrO2 spheres) in the reactor reveals interesting gap/material effects, where the

type of material dictates the position of the equilibrium and the rate (inhibition) independently. As a result, no

apparent synergistic effect or plasma-catalytic behaviour was observed for the non-porous packing materials

studied in this reaction. Within the investigated parameters, equilibrium conversions were obtained between 23

and 71%, while the rate coefficient varied between 0.027 s−1 and 0.17 s−1. This method of analysis can provide

a more fundamental insight in the overall reaction kinetics of (catalytic) plasma-based gas conversion, in order

to be able to distinguish plasma effects from true catalytic enhancement.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000471670400116 Publication Date 2019-05-08
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1385-8947 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.216 Times cited 3 Open Access Not_Open_Access: Available from 05.05.2021
Notes European Fund for Regional Development; FWOFWO, G.0254.14N ; University of Antwerp; FWO-FlandersFWO-Flanders, 11V8915N ; The authors acknowledge financial support from the European Fund for Regional Development through the cross-border collaborative Interreg V program Flanders-the Netherlands (project EnOp), the Fund for Scientific Research (FWO; Grant Number: G.0254.14N), a TOP-BOF project and an IOF-SBO (SynCO2Chem) project from the University of Antwerp. K. M. B. was funded as a PhD fellow (aspirant) of the FWOFlanders (Fund for Scientific Research-Flanders), Grant 11V8915N. Approved Most recent IF: 6.216
Call Number PLASMANT @ plasmant @UA @ admin @ c:irua:159979 Serial 5171
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Author (down) Uytdenhouwen, Y.
Title Tuning the performance of a DBD plasma reactor for CO2 reforming Type Doctoral thesis
Year 2020 Publication Abbreviated Journal
Volume Issue Pages 303 p.
Keywords Doctoral thesis; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract
Address
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 ISBN Additional Links UA library record
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:174026 Serial 6774
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Author (down) Ustarroz, J.; Ke, X.; Hubin, A.; Bals, S.; Terryn, H.
Title New insights into the early stages of nanoparticle electrodeposition Type A1 Journal article
Year 2012 Publication The journal of physical chemistry: C : nanomaterials and interfaces Abbreviated Journal J Phys Chem C
Volume 116 Issue 3 Pages 2322-2329
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Electrodeposition is an increasingly important method to synthesize supported nanoparticles, yet the early stages of electrochemical nanoparticle formation are not perfectly understood. In this paper, the early stages of silver nanoparticle electrodeposition on carbon substrates have been studied by aberration-corrected TEM, using carbon-coated TEM grids as electrochemical electrodes. In this manner we have access to as-deposited nanoparticle size distribution and structural characterization at the atomic scale combined with electrochemical measurements, which represents a breakthrough in a full understanding of the nanoparticle electrodeposition mechanisms. Whereas classical models, based upon characterization at the nanoscale, assume that electrochemical growth is only driven by direct attachment, the results reported hereafter indicate that early nanoparticle growth is mostly driven by nanocluster surface movement and aggregation. Hence, we conclude that electrochemical nulceation and growth models should be revised and that an electrochemical aggregative growth mechanism should be considered in the early stages of nanoparticle electrodeposition.
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000299584400037 Publication Date 2011-12-23
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1932-7447;1932-7455; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.536 Times cited 104 Open Access
Notes Fwo Approved Most recent IF: 4.536; 2012 IF: 4.814
Call Number UA @ lucian @ c:irua:96225 Serial 2316
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Author (down) Ustarroz, J.; Hammons, J.A.; Altantzis, T.; Hubin, A.; Bals, S.; Terryn, H.
Title A generalized electrochemical aggregative growth mechanism Type A1 Journal article
Year 2013 Publication Journal of the American Chemical Society Abbreviated Journal J Am Chem Soc
Volume 135 Issue 31 Pages 11550-11561
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract The early stages of nanocrystal nucleation and growth are still an active field of research and remain unrevealed. In this work, by the combination of aberration-corrected transmission electron microscopy (TEM) and electrochemical characterization of the electrodeposition of different metals, we provide a complete reformulation of the VolmerWeber 3D island growth mechanism, which has always been accepted to explain the early stages of metal electrodeposition and thin-film growth on low-energy substrates. We have developed a Generalized Electrochemical Aggregative Growth Mechanism which mimics the atomistic processes during the early stages of thin-film growth, by incorporating nanoclusters as building blocks. We discuss the influence of new processes such as nanocluster self-limiting growth, surface diffusion, aggregation, and coalescence on the growth mechanism and morphology of the resulting nanostructures. Self-limiting growth mechanisms hinder nanocluster growth and favor coalescence driven growth. The size of the primary nanoclusters is independent of the applied potential and deposition time. The balance between nucleation, nanocluster surface diffusion, and coalescence depends on the material and the overpotential, and influences strongly the morphology of the deposits. A small extent of coalescence leads to ultraporous dendritic structures, large surface coverage, and small particle size. Contrarily, full recrystallization leads to larger hemispherical monocrystalline islands and smaller particle density. The mechanism we propose represents a scientific breakthrough from the fundamental point of view and indicates that achieving the right balance between nucleation, self-limiting growth, cluster surface diffusion, and coalescence is essential and opens new, exciting possibilities to build up enhanced supported nanostructures using nanoclusters as building blocks.
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000323019400034 Publication Date 2013-06-28
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0002-7863;1520-5126; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 13.858 Times cited 124 Open Access
Notes Fow; Hercules Approved Most recent IF: 13.858; 2013 IF: 11.444
Call Number UA @ lucian @ c:irua:109453 Serial 1323
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Author (down) Ustarroz, J.; Gupta, U.; Hubin, A.; Bals, S.; Terryn, H.
Title Electrodeposition of Ag nanoparticles onto carbon coated TEM grids : a direct approach to study early stages of nucleation Type A1 Journal article
Year 2010 Publication Electrochemistry communications Abbreviated Journal Electrochem Commun
Volume 12 Issue 12 Pages 1706-1709
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract An innovative experimental approach to study the electrodeposition of small nanoparticles and the early stages of electrochemical nucleation and growth is presented. Carbon coated gold TEM grids are used as substrates for the electrodeposition of silver nanoparticles so that electrochemical data, FESEM, HAADFSTEM and HRTEM data can be acquired from the same sample without the need to remove the particles from the substrate. It is shown that the real distribution of nanoparticles cannot be resolved by FESEM whereas HAADFSTEM analysis confirms that a distribution of small nanoparticles (d ≈ 12 nm) coexist with large nanoparticles corresponding to a bimodal size distribution. Besides, particles grown under the same conditions have been found to present different structures such as monocrystals, polycrystals or aggregates of smaller particles.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000285904700010 Publication Date 2010-10-09
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1388-2481; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.396 Times cited 52 Open Access
Notes Fwo Approved Most recent IF: 4.396; 2010 IF: 4.287
Call Number UA @ lucian @ c:irua:87612 Serial 900
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Author (down) Ustarroz, J.; Geboes, B.; Vanrompay, H.; Sentosun, K.; Bals, S.; Breugelmans, T.; Hubin, A.
Title Electrodeposition of Highly Porous Pt Nanoparticles Studied by Quantitative 3D Electron Tomography: Influence of Growth Mechanisms and Potential Cycling on the Active Surface Area Type A1 Journal article
Year 2017 Publication ACS applied materials and interfaces Abbreviated Journal Acs Appl Mater Inter
Volume 9 Issue 9 Pages 16168-16177
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Applied Electrochemistry & Catalysis (ELCAT)
Abstract Nanoporous Pt nanoparticles (NPs) are promising fuel cell catalysts due to their large surface area and increased electrocatalytic activity towards the oxygen reduction reaction (ORR). Herein, we report on the infuence of the growth mechanisms on the surface properties of electrodeposited Pt dendritic NPs with large surface areas. The electrochemically active surface was studied by hydrogen underpotential deposition (HUPD) and compared for the rst time to high angle annular dark eld scanning transmission electron microscopy (HAADF-STEM) quantitative 3D electron tomography of individual nanoparticles. Large nucleation overpotential leads to a large surface coverage of Pt roughened spheroids, which provide large roughness factor (Rf ) but low mass-speci c electrochemically active surface area (EASA). Lowering the nucleation overpotential leads to highly porous Pt NPs with pores protruding to the center of the structure. At the expense of smaller Rf , the obtained EASA values of these structures are in the range of these of large surface area supported fuel cell catalysts. The active surface area of the Pt dendritic NPs was measured by electron tomography and it was found that the potential cycling in the H adsorption/desorption and Pt oxidation/reduction region, which is generally performed to determine the EASA, leads to a signi cant reduction of that surface area due to a partial collapse of their dendritic and porous morphology. Interestingly, the extrapolation of the microscopic tomography results to macroscopic electrochemical parameters indicated that the surface properties measured by H UPD are comparable to the values measured on individual NPs by electron tomography after the degradation caused by the H UPD measurement. These results highlight that the combination of electrochemical and quantitative 3D surface analysis techniques is essential to provide insights into the surface properties, the electrochemical stability and, hence, the applicability of these materials. Moreover, it indicates that care must be taken with widely used electrochemical methods of surface area determination, especially in the case of large surface area and possibly unstable nanostructures, since the measured surface can be strongly a ected by the measurement itself.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000401782500028 Publication Date 2017-04-18
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 24 Open Access OpenAccess
Notes Jon Ustarroz acknowledges funding from the Fonds Wetenschappelijk Onderzoek in Flanders (FWO, postdoctoral grant 12I7816N). S. Bals acknowledges funding from the European Research Council (Starting Grant No. COLOURATOMS 335078). S.B. and T.B. acknowledge the University of Antwerp for nancial support in the frame of a GOA project. H.V. gratefully acknowledges nancial support by the Flemish Fund for Scienti c Research (FWO Vlaanderen). All the authors acknowledge Laurens Stevaert for his contribution to the work presented in this manuscript. (ROMEO:white; preprint:; postprint:restricted 12 months embargo; pdfversion:cannot); ECAS_Sara Approved Most recent IF: 7.504
Call Number EMAT @ emat @ c:irua:142345UA @ admin @ c:irua:142345 Serial 4552
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Author (down) Ustarroz, J.; Altantzis, T.; Hammons, J.A.; Hubin, A.; Bals, S.; Terryn, H.
Title The role of nanocluster aggregation, coalescence, and recrystallization in the electrochemical deposition of platinum nanostructures Type A1 Journal article
Year 2014 Publication Chemistry of materials Abbreviated Journal Chem Mater
Volume 26 Issue 7 Pages 2396-2406
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract By using an optimized characterization approach that combines aberration-corrected transmission electron microscopy, electron tomography, and in situ ultrasmall angle X-ray scattering (USAXS), we show that the early stages of Pt electrochemical growth on carbon substrates may be affected by the aggregation, self-alignment, and partial coalescence of nanoclusters of d ≈ 2 nm. The morphology of the resulting nanostructures depends on the degree of coalescence and recrystallization of nanocluster aggregates, which in turn depends on the electrodeposition potential. At low overpotentials, a self-limiting growth mechanism may block the epitaxial growth of primary nanoclusters and results in loose dendritic aggregates. At more negative potentials, the extent of nanocluster coalescence and recrystallization is larger and further growth by atomic incorporation may be allowed. On one hand, this suggests a revision of the VolmerWeber island growth mechanism. Whereas this theory has traditionally assumed direct attachment as the only growth mechanism, it is suggested that nanocluster self-limiting growth, aggregation, and coalescence should also be taken into account during the early stages of nanoscale electrodeposition. On the other hand, depending on the deposition potential, ultrahigh porosities can be achieved, turning electrodeposition in an ideal process for highly active electrocatalyst production without the need of using high surface area carbon supports.
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000334572300026 Publication Date 2014-03-10
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0897-4756;1520-5002; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 9.466 Times cited 55 Open Access Not_Open_Access
Notes FWO; contract no. FWOAL527 Approved Most recent IF: 9.466; 2014 IF: 8.354
Call Number UA @ lucian @ c:irua:116956 Serial 2916
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Author (down) Ulu Okudur, F.; D'Haen, J.; Vranken, T.; De Sloovere, D.; Verheijen, M.; Karakulina, O.M.; Abakumov, A.M.; Hadermann, J.; Van Bael, M.K.; Hardy, A.
Title Ti surface doping of LiNi0.5Mn1.5O4−δpositive electrodes for lithium ion batteries Type A1 Journal article
Year 2018 Publication RSC advances Abbreviated Journal Rsc Adv
Volume 8 Issue 13 Pages 7287-7300
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract The particle surface of LiNi0.5Mn1.5O4−δ (LNMO), a Li-ion battery cathode material, has been modified by Ti cation doping through a hydrolysis–condensation reaction followed by annealing in oxygen. The effect of different annealing temperatures (500–850 °C) on the Ti distribution and electrochemical performance of the surface modified LNMO was investigated. Ti cations diffuse from the preformed amorphous ‘TiOx’ layer into the LNMO surface during annealing at 500 °C. This results in a 2–4 nm thick Ti-rich spinel surface having lower Mn and Ni content compared to the core of the LNMO particles, which was observed with scanning transmission electron microscopy coupled with compositional EDX mapping. An increase in the annealing temperature promotes the formation of a Ti bulk doped LiNi(0.5−w)Mn(1.5+w)−tTitO4 phase and Ti-rich LiNi0.5Mn1.5−yTiyO4 segregates above 750 °C. Fourier-transform infrared spectrometry indicates increasing Ni–Mn ordering with annealing temperature, for both bare and surface modified LNMO. Ti surface modified LNMO annealed at 500 °C shows a superior cyclic stability, coulombic efficiency and rate performance compared to bare LNMO annealed at 500 °C when cycled at 3.4–4.9 V vs. Li/Li+. The improvements are probably due to suppressed Ni and Mn dissolution with Ti surface doping.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000425508900064 Publication Date 2018-02-13
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2046-2069 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.108 Times cited 9 Open Access OpenAccess
Notes This research is supported by the Research Foundation Flanders (FWO Vlaanderen, grant number G040116N). This project receives the support of the European Union, the European Regional Development Fund ERDF, Flanders Innovation & Entrepreneurship and the Province of Limburg (project 936). Greet Cuyvers and Gilles Bonneux (UHasselt) are acknowledged for the ICP-AES sample preparation and measurements. Vera Meynen and Karen Leyssens (Antwerp University, Belgium) are acknowledged for the BET measurements. Special thanks to Bart Ruttens (UHasselt) for XRD measurements and discussions on the refinements. Approved Most recent IF: 3.108
Call Number EMAT @ emat @c:irua:149513 Serial 4905
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Author (down) Ulu Okudur, F.; Batuk, M.; Hadermann, J.; Safari, M.; De Sloovere, D.; Kumar Mylavarapu, S.; Joos, B.; D'Haen, J.; Van Bael, M.K.; Hardy, A.
Title Solution-gel-based surface modification of LiNi0.5Mn1.5O4-δ with amorphous Li-Ti-O coating Type A1 Journal article
Year 2023 Publication RSC advances Abbreviated Journal
Volume 13 Issue 47 Pages 33146-33158
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract LNMO (LiNi0.5Mn1.5O4-delta) is a high-energy density positive electrode material for lithium ion batteries. Unfortunately, it suffers from capacity loss and impedance rise during cycling due to electrolyte oxidation and electrode/electrolyte interface instabilities at high operating voltages. Here, a solution-gel synthesis route was used to coat 0.5-2.5 mu m LNMO particles with amorphous Li-Ti-O (LTO) for improved Li conduction, surface structural stability and cyclability. High-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) analysis coupled with energy dispersive X-ray (EDX) showed Ti-rich amorphous coatings/islands or Ti-rich spinel layers on many of the LTO-modified LNMO facets, with a thickness varying from about 1 to 10 nm. The surface modification in the form of amorphous islands was mostly possible on high-energy crystal facets. Physicochemical observations were used to propose a molecular mechanism for the surface modification, combining insights from metalorganic chemistry with the crystallographic properties of LNMO. The improvements in functional properties were investigated in half cells. The cell impedance increased faster for the bare LNMO compared to amorphous LTO modified LNMO, resulting in R-ct values as high as 1247 Omega (after 1000 cycles) for bare LNMO, against 216 Omega for the modified material. At 10C, the modified material boosted a 15% increase in average discharge capacity. The improvements in electrochemical performance were attributed to the increase in electrochemically active surface area, as well as to improved HF-scavenging, resulting in the formation of protective byproducts, generating a more stable interface during prolonged cycling.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 001102666700001 Publication Date 2023-11-09
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2046-2069 ISBN Additional Links UA library record; WoS full record
Impact Factor 3.9 Times cited Open Access
Notes Approved Most recent IF: 3.9; 2023 IF: 3.108
Call Number UA @ admin @ c:irua:202091 Serial 9096
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Author (down) Ullah, S.; Hussain, A.; Syed, W.A.; Saqlain, M.A.; Ahmad, I.; Leenaerts, O.; Karim, A.
Title Band-gap tuning of graphene by Be doping and Be, B co-doping : a DFT study Type A1 Journal article
Year 2015 Publication RSC advances Abbreviated Journal Rsc Adv
Volume 5 Issue 5 Pages 55762-55773
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract First-principles density functional theory (DFT) calculations were carried out to investigate the structural and electronic properties of beryllium (Be) doped and Be and boron (B) co-doped graphene systems. We observed that not only the concentration of impurity atoms is important to tune the band-gap to some desired level, but also the specific substitution sites play a key role. In our system, which consists of 32 atoms, a maximum of 4Be and, in the co-doped state, 2Be and 3B atom substitutions are investigated. Both dopants are electron deficient relative to C atoms and cause the Fermi level to shift downward (p-type doping). A maximum band gap of 1.44 eV can be achieved on incorporation of 4Be atoms. The introduction of Be is more sensitive in terms of geometry and stability than B. However, in opening the energy gap, Be is more effective than B and N (nitrogen). Our results offer the possibility to modify the band-gap of graphene sufficiently for utilization in diverse electronic device applications.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000357803200018 Publication Date 2015-06-17
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2046-2069; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.108 Times cited 33 Open Access
Notes ; ; Approved Most recent IF: 3.108; 2015 IF: 3.840
Call Number c:irua:127167 Serial 216
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