TY - JOUR
A1 - Smekhova, A.
A1 - Kuzmin, A.
A1 - Siemensmeyer, K.
A1 - Abrudan, R.
A1 - Reinholz, Uwe
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Schneider, M.
A1 - Laplanche, G.
A1 - Yusenko, Kirill
T1 - Inner relaxations in equiatomic single-phase high-entropy Cantoralloy
N2 - The superior properties of high-entropy multi-functional materials are strongly connected with their atomic heterogeneity through many different local atomic interactions. The detailed element-specific studies on a local scale can provide insight into the primary arrangements of atoms in multicomponent systems and benefit to unravel the role of individual components in certain macroscopic properties of complex compounds. Herein, multi-edge X-ray absorption spectroscopy combined with reverse Monte Carlo simulations was used to explore a homogeneity of the local crystallographic ordering and specific structure relaxations of each constituent in the equiatomic single-phase facecentered cubic CrMnFeCoNi high-entropy alloy at room temperature. Within the considered fitting approach, all five elements of the alloy were found to be distributed at the nodes of the fcc lattice without any signatures of the additional phases at the atomic scale and exhibit very close statistically averaged interatomic distances (2.54 – 2.55 Å) with their nearest-neighbors. Enlarged structural displacements were found solely for Cr atoms. The macroscopic magnetic properties probed by conventional magnetometry demonstrate no opening of the hysteresis loops at 5 K and illustrate a complex character of the long-range magnetic order after field-assisted cooling in ± 5 T. The observed magnetic behavior is assigned to effects related to structural relaxations of Cr. Besides, the advantages and limitations of the reverse Monte Carlo approach to studies of multicomponent systems like high-entropy alloys are highlighted.
KW - Magnetism
KW - High-entropy alloys
KW - Reverse Monte Carlo (RMC)
KW - Element-specific spectroscopy
KW - Extended X-ray absorption fine structure (EXAFS)
KW - X-ray absorption near edge structure (XANES)
PY - 2022
DO - https://doi.org/10.1016/j.jallcom.2022.165999
SN - 0925-8388
VL - 920
SP - 1
EP - 31
PB - Elsevier
AN - OPUS4-55457
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Yusenko, Kirill
A1 - Emmerling, Franziska
A1 - de Oliveira Guilherme Buzanich, Ana
T1 - X-Ray absorption spectroscopy to study multicomponent materials
N2 - Detailed study of multicomponent systems in solid-state as well as in solution using X-ray diffraction and X-ray spectroscopy is one of the most common topics in modern materials chemistry. 5-6 component high-entropy alloys such as fcc- and bcc-structured AlxCoCrFeNi and fluorescent nanoparticles based on fluorite-structured SrF2 doped by rare-earth metals in organic solutions have high complexity and their local structure cannot be resolved using only diffraction. X-ray absorption spectroscopy should be applied to understand peculiarities in their local structure and make a link between structure on short and long ranges and their macroscopic properties. Here, based on two representativee examples, we discuss how a combination of several X-ray absorption edges might give new insights into complex materials.
T2 - Virtual meeting of the African Light Source
CY - Online meeting
DA - 15.11.2021
KW - EXAFS
KW - Synchrotron studies
PY - 2021
AN - OPUS4-54014
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lumpe, H.
A1 - Menke, A.
A1 - Haisch, C.
A1 - Mayer, P.
A1 - Kabelitz, Anke
A1 - Yusenko, Kirill
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Block, T.
A1 - Pöttgen, R.
A1 - Emmerling, Franziska
A1 - Daumann, L. J.
T1 - The Earlier the Better: Structural Analysis and Separation of Lanthanides with Pyrroloquinoline Quinone
N2 - Lanthanides (Ln) are critical raw materials, however, their mining and purification have a considerable negative environmental impact and sustainable recycling and separation strategies for these elements are needed. In this study, the precipitation and solubility behavior of Ln complexes with pyrroloquinoline quinone (PQQ), the cofactor of recently discovered lanthanide (Ln) dependent methanol Dehydrogenase (MDH) enzymes, is presented. In this context, the molecular structure of a biorelevant europium PQQ complex was for the first time elucidated outside a protein environment.
The complex crystallizes as an inversion symmetric dimer, Eu2PQQ2, with binding of Eu in the biologically relevant pocket of PQQ. LnPQQ and Ln1Ln2PQQ complexes were characterized by using inductively coupled Plasma mass spectrometry (ICP-MS), infrared (IR) spectroscopy, 151Eu-Mössbauer spectroscopy, X-ray total scattering, and Extended X-ray absorption fine structure (EXAFS). It is shown that a natural enzymatic cofactor is capable to achieve Separation by precipitation of the notoriously similar, and thus difficult to separate, lanthanides to some extent.
KW - Lanthanides
KW - Structural Analysis
KW - Separation
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510821
DO - https://doi.org/10.1002/chem.202002653
SN - 0947-6539
VL - 26
SP - 1
EP - 8
PB - WILEY-VCH Verlag GmbH & co. KGaA
AN - OPUS4-51082
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - de O. Primo, J.
A1 - Horsth, D.F.
A1 - de S. Correa, J.
A1 - Das, A.
A1 - Bittencourt, C.
A1 - Umek, P.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Radtke, Martin
A1 - Yusenko, Kirill
A1 - Zanetta, C.
A1 - Anaissi, F.J.
T1 - Synthesis and Characterization of Ag/ZnO Nanoparticles for Bacteria Disinfection in Water
N2 - n this study, two green synthesis routes were used for the synthesis of Ag/ZnO nanoparticles, using cassava starch as a simple and low-cost effective fuel and Aloe vera as a reducing and stabilizing agent. The Ag/ZnO nanoparticles were characterized and used for bacterial dis-
infection of lake water contaminated with Escherichia coli (E. coli). Characterization indicated the formation of a face-centered cubic structure of metallic silver nanoparticles with no insertion of Ag into the ZnO hexagonal wurtzite structure. Physicochemical and bacteriological analyses described in “Standard Methods for the Examination of Water and Wastewater” were used to evaluate the efficiency of the treatment. In comparison to pure ZnO, the synthesized Ag/ZnO nanoparticles showed high efficiencies against Escherichia coli (E. coli) and general coliforms present in the lake
water. These pathogens were absent after treatment using Ag/ZnO nanoparticles. The results indicate that Ag/ZnO nanoparticles synthesized via green chemistry are a promising candidate for the treatment of wastewaters contaminated by bacteria, due to their facile preparation, low-cost synthesis,and disinfection efficiency.
KW - Synchrotron
KW - BAMline
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-562440
DO - https://doi.org/10.3390/nano12101764
SN - 2079-4991
VL - 12
IS - 10
SP - 1
EP - 18
PB - MDPI
CY - Basel
AN - OPUS4-56244
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dubey, A.
A1 - Hon Keat, C.
A1 - Shvartsman, V.
A1 - Yusenko, Kirill
A1 - Escobar, M.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Hagemann, U.
A1 - Kovalenko, S.
A1 - Stächler, J.
A1 - Lupascu, D.
T1 - Mono-, Di-, and Tri-valent Cation Doped BiFe0.95Mn0.05O3 Nanoparticles: Ferroelectric Photocatalysts
N2 - The ferroelectricity of multivalent co-doped Bismuth ferrite (BiFeO3; BFO) nanoparticles (NPs) is revealed and utilized for light photocatalysis exploiting their narrow electronic band gap. The photocatalytic activity of ferroelectric photocatalysts BiFe0.95Mn0.05O3 (BFM) NPs and mono-, di-, or tri-valent cations (Ag+, Ca2+, Dy3+; MDT) co-incorporated BFM NPs are studied under ultrasonication and in acidic conditions. We find that such doping enhances the photocatalytic activity of the ferroelectric NPs approximately three times. The correlation of the photocatalytic activity with structural, optical, and electrical properties of the doped NPs is established. The increase of spontaneous polarization by the mono- and tri-valent doping is one of the major factors in enhancing the photocatalytic performance along with other factors such as stronger light absorption in the visible range, low recombination rate of charge carriers and larger surface area of NPs. A-site doping of BFO NPs by divalent elements suppresses the polarization, whereas trivalent (Dy3+) and monovalent (Ag+) cations provide an increase of polarization. The depolarization field in these single domain NPs acts as a driving force to mitigate recombination of the photoinduced charge carriers.
KW - Piezoresponse
KW - Bismuth Ferrite
KW - Nanoparticles
KW - Photocatalysis
KW - Ferroelectric
KW - Polarization
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-557230
DO - https://doi.org/10.1002/adfm.202207105
SN - 1616-301X
SP - 1
EP - 16
PB - Wiley
AN - OPUS4-55723
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Glazyrin, Konstantin
A1 - Spektor, Kristina
A1 - Bykov, Maxim
A1 - Dong, Weiwei
A1 - Yu, Ji‐Hun Yu
A1 - Yang, Sangsun Yang
A1 - Lee, Jai‐Sung Lee
A1 - Divinski, Sergiy V.
A1 - Hanfland, Michael
A1 - Yusenko, Kirill
T1 - High‐Entropy Alloys and Their Affinity with Hydrogen: From Cantor to Platinum Group Elements Alloys
N2 - AbstractProperties of high‐entropy alloys are currently in the spotlight due to their promising applications. One of the least investigated aspects is the affinity of these alloys to hydrogen, its diffusion, and reactions. In this study, high pressure is applied at ambient temperature and stress‐induced diffusion of hydrogen is investigated into the structure of high‐entropy alloys (HEA) including the famous Cantor alloy as well as less known, but nevertheless important platinum group (PGM) alloys. By applying X‐ray diffraction to samples loaded into diamond anvil cells, a comparative investigation of transition element incorporating HEA alloys in Ne and H2 pressure‐transmitting media is performed at ambient temperature. Even under stresses far exceeding conventional industrial processes, both Cantor and PGM alloys show exceptional resistance to hydride formation, on par with widely used industrial grade Cu–Be alloys. The observations inspire optimism for practical HEA applications in hydrogen‐relevant industry and technology (e.g., coatings, etc), particularly those related to transport and storage.
KW - XRD
KW - HIgh entropy,
KW - Cantor
KW - Alloys
KW - Synchrotron
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-604170
DO - https://doi.org/10.1002/advs.202401741
SP - 1
EP - 8
PB - Wiley VHC-Verlag
AN - OPUS4-60417
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gomes, Bruna F.
A1 - Prokop, Martin
A1 - Bystron, Tomas
A1 - Loukrakpam, Rameshwori
A1 - Melke, Julia
A1 - Lobo, Carlos M. S.
A1 - Fink, Michael
A1 - Zhu, Mengshu
A1 - Voloshina, Elena
A1 - Kutter, Maximilian
A1 - Hoffmann, Hendrik
A1 - Yusenko, Kirill V.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Röder, Bettina
A1 - Bouzek, Karel
A1 - Paulus, Beate
A1 - Roth, Christina
T1 - Following Adsorbed Intermediates on a Platinum Gas Diffusion Electrode in H3PO3-Containing Electrolytes Using In Situ X-ray Absorption Spectroscopy
N2 - One of the challenges of high-temperature polymer electrolyte membrane fuel cells is the poisoning of the Pt catalystwith H3PO4. H3PO4 is imbibed into the routinely used polybenzimidazole-based membranes, which facilitate Proton conductivity in the temperature range of 120−200 °C. However, when leached out of the membrane by water produced during operation, H3PO4 adsorbs on the Pt catalyst surface, blocking the active sites and hindering the oxygen reduction reaction (ORR).
The reduction of H3PO4 to H3PO3, which occurs at the anode due to a combination of a low potential and the presence of gaseous H2, has been investigated as an additional important contributing factor to the observed poisoning effect. H3PO3 has an affinity toward adsorption on Pt surfaces even greater than that of H2PO4 −. In this work, we investigated the poisoning effect of both H3PO3 and H3PO4 using a half-cell setup with a gas diffusion electrode under ambient conditions. By means of in situ X-ray absorption spectroscopy, it was possible to follow the signature of different species adsorbed on the Pt nanoparticle catalyst (H, O, H2PO4 −, and H3PO3) at different potentials under ORR conditions in various electrolytes (HClO4, H3PO4, and H3PO3). It was found that H3PO3 adsorbs in a pyramidal configuration P(OH)3 through a Pt−P bond. The competition between H3PO4 and H3PO3 adsorption was studied, which should allow for a better understanding of the catalyst poisoning mechanism and thus assist in the development of strategies to mitigate this phenomenon in the future by minimizing H3PO3 generation by, for example, improved catalyst design or adapted operation conditions or changes in the electrolyte composition.
KW - H3PO4 life cycle
KW - XAS
KW - In situ coupling
KW - High-temperature fuel cells
KW - H3PO3,
KW - Δμ XANES
PY - 2022
DO - https://doi.org/10.1021/acscatal.2c02630
SN - 2155-5435
VL - 12
IS - 18
SP - 11472
EP - 11484
PB - American Chemical Society (ACS)
AN - OPUS4-64733
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Smekhova, A.
A1 - Kuzmin, A.
A1 - Siemensmeyer, K.
A1 - Luo, C.
A1 - Chen, K.
A1 - Radu, F.
A1 - Weschke, E.
A1 - Reinholz, Uwe
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Yusenko, Kirill
T1 - Al-driven peculiarities of local coordination and magnetic properties in single-phase Alx-CrFeCoNi high-entropy alloys
N2 - Modern design of superior multi-functional alloys composed of several principal components requires in-depth studies of their local structure for developing desired macroscopic properties. Herein, peculiarities of atomic arrangements on the local scale and electronic states of constituent elements in the single-phase face-centered cubic (fcc)- and body-centered cubic (bcc)-structured high-entropy Alx-CrFeCoNi alloys (x = 0.3 and 3, respectively) are explored by element-specific X-ray absorption spectroscopy in hard and soft X-ray energy ranges. Simulations based on the reverse Monte Carlo approach allow to perform a simultaneous fit of extended X-ray absorption fine structure spectra recorded at K absorption edges of each 3d constituent and to reconstruct the local environment within the first coordination shells of absorbers with high precision. The revealed unimodal and bimodal distributions of all five elements are in agreement with structure-dependent magnetic properties of studied alloys probed by magnetometry. A degree of surface atoms oxidation uncovered by soft X-rays suggests different kinetics of oxide formation for each type of constituents and has to be taken into account. X-ray magnetic circular dichroism technique employed at L2,3 absorption edges of transition metals demonstrates reduced magnetic moments of 3d metal constituents in the sub-Surface region of in situ cleaned fcc-structured Al0.3-CrFeCoNi compared to their bulk values. Extended to nanostructured versions of multicomponent alloys, such studies would bring new insights related to effects of high entropy mixing on low dimensions.
KW - X-ray magnetic circular dichroism (XMCD)
KW - High-entropy alloys
KW - Reverse Monte Carlo
KW - Magnetism
KW - Element-specific spectroscopy
KW - Extended X-ray absorption fine structure (EXAFS)
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-530668
DO - https://doi.org/10.1007/s12274-021-3704-5
SN - 1998-0124
VL - 15
IS - 6
SP - 4845
EP - 4858
PB - Springer
AN - OPUS4-53066
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Smekhova, Alevtina
A1 - Gaertner, Daniel
A1 - Kuzmin, Alexei
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Schuck, Goetz
A1 - Zizak, Ivo
A1 - Wilde, Gerhard
A1 - Yusenko, Kirill
A1 - Divinski, Sergiy
T1 - Anomalies in the short-range local environment and atomic diffusion in single crystalline equiatomic CrMnFeCoNi high-entropy alloy
N2 - AbstractMulti-edge extended X-ray absorption fine structure (EXAFS) spectroscopy combined with reverse Monte Carlo (RMC) simulations was used to probe the details of element-specific local coordinations and component-dependent structure relaxations in single crystalline equiatomic CrMnFeCoNi high-entropy alloy as a function of the annealing temperature. Two representative states, namely a high-temperature state, created by annealing at 1373 K, and a low-temperature state, produced by long-term annealing at 993 K, were compared in detail. Specific features identified in atomic configurations of particular principal components indicate variations in the local environment distortions connected to different degrees of compositional disorder at the chosen representative temperatures. The detected changes provide new atomistic insights and correlate with the existence of kinks previously observed in the Arrhenius dependencies of component diffusion rates in the CrMnFeCoNi high-entropy alloy.
KW - Electrical and Electronic Engineering
KW - General Materials Science
KW - Condensed Matter Physics
KW - Atomic and Molecular Physics, and Optics
KW - CCMat
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597687
DO - https://doi.org/10.1007/s12274-024-6443-6
SN - 1998-0124
VL - 17
IS - 6
SP - 5336
EP - 5348
PB - Springer Science and Business Media LLC
AN - OPUS4-59768
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lumpe, H.
A1 - Menke, Annika
A1 - Haisch, C.
A1 - Mayer, P.
A1 - Kabelitz, Anke
A1 - Yusenko, Kirill
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Block, T.
A1 - Pöttgen, R.
A1 - Emmerling, Franziska
A1 - Daumann, L.
T1 - The Earlier the Better: Structural Analysis and Separation of Lanthanides with Pyrroloquinoline Quinone
N2 - Lanthanides (Ln) are critical raw materials, however, their mining and purification have a considerable negative environmental impact and sustainable recycling and separation strategies for these elements are needed. In this study, the precipitation and solubility behavior of Ln complexes with pyrroloquinoline quinone (PQQ), the cofactor of recently discovered lanthanide (Ln) dependent methanol dehydrogenase (MDH) enzymes, is presented. In this context, the molecular structure of a biorelevant europium PQQ complex was for the first time elucidated outside a protein environment. The complex crystallizes as an inversion symmetric dimer, Eu2PQQ2, with binding of Eu in the biologically relevant pocket of PQQ. LnPQQ and Ln1Ln2PQQ complexes were characterized by using inductively coupled plasma mass spectrometry (ICP‐MS), infrared (IR) spectroscopy, 151Eu‐Mössbauer spectroscopy, X‐ray total scattering, and extended X‐ray absorption fine structure (EXAFS). It is shown that a natural enzymatic cofactor is capable to achieve separation by precipitation of the notoriously similar, and thus difficult to separate, lanthanides to some extent.
KW - PQQ
KW - Lanthanoide
KW - Coordination chemistry
KW - Rare earth elements separations
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-512707
DO - https://doi.org/10.1002/chem.202002653
VL - 26
IS - 44
SP - 10133
EP - 10139
AN - OPUS4-51270
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -