TY - JOUR A1 - Flatken, M. A. A1 - Radicchi, E. A1 - Wendt, R. A1 - de Oliveira Guilherme Buzanich, Ana A1 - Härk, E. A1 - Pascual, J. A1 - Mathies, F. A1 - Shargaieva, O. A1 - Prause, A. A1 - Dallmann, A. A1 - De Angelis, F. A1 - Hoell, A. A1 - Abate, A. T1 - Role of the Alkali Metal Cation in the Early Stages of Crystallization of Halide Perovskites N2 - ABX3 metal halide perovskites revolutionized the research and development of new optoelectronics, including solar cells and light-emitting diodes. Processing polycrystalline thin films from precursor solutions is one of the core advantages of these materials since it enables versatile and cost-effective manufacturing. The perovskite film morphology, that is, continuous substrate coverage and low surface roughness, is of paramount importance for highly efficient solar cells and optoelectronic devices in general. Controlling the chemistry of precursor solutions is one of the most effective strategies to manage the perovskite film morphology. Herein, we show the fundamental influence of the A-site cation composition on the perovskite precursor arrangement and the consequent film formation. Extended X-ray absorption fine structure spectroscopy and small-angle X-ray scattering give unprecedented insights into the complex structural chemistry of the perovskite precursors and, in particular, their repulsive interactions as a crucial parameter for colloidal stability. Combining these techniques with in situ grazing incidence wide-angle X-ray scattering during thin-film formation allows us to identify the mechanism for using alkali metals as a decisive criterion to control the colloidal stability of the perovskite precursor and thus the thin-film morphology. We illustrate the fundamental principle behind the systematic use of alkali metals regardless of whether they are incorporated in the lattice or not. Hence, this work provides tools to selectively control the morphology and crystal growth in present and future systems KW - MAPbI3 perovskites KW - Halide Perovskites KW - X-ray absorption spectroscopy PY - 2022 DO - https://doi.org/10.1021/acs.chemmater.1c03563 SN - 0897-4756 VL - 34 IS - 3 SP - 1121 EP - 1131 PB - American Chemical Society AN - OPUS4-54713 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 - Taylor, J. A1 - Thakur, S. A1 - Radu, F. A1 - Weschke, E. A1 - de Oliveira Guilherme Buzanich, Ana A1 - Xiao, B. A1 - Savan, A. A1 - Yusenko, Kirill A1 - Ludwig, A. T1 - Local structure and magnetic properties of a nanocrystalline Mn-rich Cantor alloy thin film down to the atomic scale N2 - The huge atomic heterogeneity of high-entropy materials along with a possibility to unravel the behavior of individual components at the atomic scale suggests a great promise in designing new compositionally complex systems with the desired multi-functionality. Herein, we apply multi-edge X-ray absorption spectroscopy (extended X-ray absorption fine structure (EXAFS), X-ray absorption near edge structure (XANES), and X-ray magnetic circular dichroism (XMCD)) to probe the structural, electronic, and magnetic properties of all individual constituents in the single-phase face-centered cubic (fcc)-structured nanocrystalline thin film of Cr20Mn26Fe18Co19Ni17 (at.%) high-entropy alloy on the local scale. The local crystallographic ordering and component-dependent lattice displacements were explored within the reverse Monte Carlo approach applied to EXAFS spectra collected at the K absorption edges of several constituents at room temperature. A homogeneous short-range fcc atomic environment around the absorbers of each type with very similar statistically averaged interatomic distances (2.54–2.55 Å) to their nearest-neighbors and enlarged structural relaxations of Cr atoms were revealed. XANES and XMCD spectra collected at the L2,3 absorption edges of all principal components at low temperature from the oxidized and in situ cleaned surfaces were used to probe the oxidation states, the changes in the electronic structure, and magnetic behavior of all constituents at the surface and in the sub-surface volume of the film. The spin and orbital magnetic moments of Fe, Co, and Ni components were quantitatively evaluated. The presence of magnetic phase transitions and the co-existence of different magnetic phases were uncovered by conventional magnetometry in a broad temperature range. 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 magnetic circular dichroism (XMCD), PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-578254 DO - https://doi.org/10.1007/s12274-022-5135-3 SN - 1998-0124 SP - 5626 PB - Springer AN - OPUS4-57825 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Liu, Yanchen A1 - Guilherme Buzanich, Ana A1 - Alippi, Paola A1 - Montoro, Luciano A. A1 - Lee, Kug‐Seung A1 - Jeon, Taeyeol A1 - Weißer, Kilian A1 - Karlsen, Martin A. A1 - Russo, Patrícia A. A1 - Pinna, Nicola T1 - FeNb 2 O 6 as a High‐Performance Anode for Sodium‐Ion Batteries Enabled by Structural Amorphization Coupled with NbO 6 Local Ordering N2 - Pseudocapacitance-type transition metal oxides have been extensively investigated as anodes for lithium-ion batteries (LIBs). Currently, they are also gaining attention for sodium-ion batteries (SIBs) due to their low volume change and safety. However, their performance in sodium storage remains limited, primarily due to the larger Na+ ion radius. Here, for the first time, an iron niobate is reported with a columbite structure as a high-performance sodium storage anode. The presence of iron triggers the loss of long-range order through disorder of the FeO6 octahedra local structure, subsequently allowing reversible sodium storage in an amorphous phase. Simultaneously, the formation of short-range ordered zigzag-chain structures within the NbO6 planes creates a “skeleton” that offers abundant active sites for pseudocapacitive ion storage and enhanced ion diffusion pathways. These characteristics of FeNb2O6 make it an effective intercalation host, offering high capacity along with fast Na+ kinetics, as demonstrated through operando and ex situ characterizations. It leads to an applicable reversible capacity (>300 mAh g−1) with a favorable average voltage of ≈0.6 V and excellent rate capability (180.4 mAh g−1 at a current density of 2 A g−1). This study provides insights into the development of intrinsically active transition metal oxides for Na+-ion intercalation. KW - SIB KW - XAS KW - Sodium-ion Batteries PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654931 DO - https://doi.org/10.1002/adma.202504100 SN - 0935-9648 VL - 37 IS - 46 SP - 1 EP - 13 PB - Wiley AN - OPUS4-65493 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Yao, Xingyu A1 - Antunes, Margarida M. A1 - Guilherme Buzanich, Ana A1 - Cabanelas, Pedro A1 - Valente, Anabela A. A1 - Pinna, Nicola A1 - Russo, Patrícia A. T1 - Formation, Phase Transition, Surface, and Catalytic Properties of Cubic ZrO 2 Nanocrystals N2 - Pseudocapacitance-type transition metal oxides have been extensively investigated as anodes for lithium-ion batteries (LIBs). Currently, they are also gaining attention for sodium-ion batteries (SIBs) due to their low volume change and safety. However, their performance in sodium storage remains limited, primarily due to the larger Na+ ion radius. Here, for the first time, an iron niobate is reported with a columbite structure as a high-Performance sodium storage anode. The presence of iron triggers the loss of long-rangeorder through disorder of the FeO6 octahedra local structure, subsequentlyallowing reversible sodium storage in an amorphous phase. Simultaneously, the formation of short-range ordered zigzag-chain structures within the NbO6 planes creates a “skeleton” that offers abundant active sites forpseudocapacitive ion storage and enhanced ion diffusion pathways. These characteristics of FeNb2O6 make it an effective intercalation host, offering high capacity along with fast Na+ kinetics, as demonstrated through operando and ex situ characterizations. It leads to an applicable reversible capacity (>300 mAh g−1) with a favorable average voltage of ≈0.6 V and excellent rate capability (180.4 mAh g−1 at a current density of 2 A g−1). This study provides insights into the development of intrinsically active transition metal oxides for Na+-ion intercalation. KW - XAS KW - Sodium-ion Batteries PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654955 DO - https://doi.org/10.1021/acs.chemmater.5c01483 SN - 0897-4756 VL - 37 IS - 21 SP - 8568 EP - 8580 PB - American Chemical Society (ACS) AN - OPUS4-65495 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gao, S. A1 - Hou, J. A1 - Deng, Z. A1 - Wang, T. A1 - Beyer, Sebastian A1 - de Oliveira Guilherme Buzanich, Ana A1 - Richardson, J. J. A1 - Rawal, A. A1 - Seidel, R. A1 - Zulkifli, M. Y. A1 - Li, W. A1 - Bennett, T. D. A1 - Cheetham, A. K. A1 - Liang, K. T1 - Improving the Acidic Stability of Zeolitic Imidazolate Frameworks by Biofunctional Molecules N2 - Zeolitic imidazolate frameworks (ZIFs) have been widely investigated for their use in separation, gas adsorption, catalysis, and biotechnology. Their practical applications, however, can be hampered by their structural instability in humid acidic conditions. Here, guided by density functional theory calculations, we demonstrate that the acidic stability of two polymorphic ZIFs (i.e., ZIF-8 and ZIF-L) can be enhanced by the incorporation of functional groups on polypeptides or DNA. A range of complementary synchrotron investigations into the local chemical structure and bonding environment suggest that the enhanced acidic stability arises from the newly established coordinative interactions between the Zn centers and the inserted carboxylate (for polypeptides) or phosphate (for DNA) groups, both of which have lower pKas than the imidazolate ligand. With functional biomolecular homologs (i.e., enzymes), we demonstrate a symbiotic stability reinforcement effect, i.e., the encapsulated biomolecules stabilize the ZIF matrix while the ZIF exoskeleton protects the enzyme from denaturation. KW - Zeolitic Imidazolate Frameworks KW - Biofunctional Molecules KW - X-ray Absorption Spectroscopy PY - 2019 DO - https://doi.org/10.1016/j.chempr.2019.03.025 VL - 5 IS - 6 SP - 1597 EP - 1608 PB - Elsevier Inc. AN - OPUS4-48702 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wintzheimer, S. A1 - Szczerba, Wojciech A1 - de Oliveira Guilherme Buzanich, Ana A1 - Kashiwaya, S. A1 - Klein, A. A1 - Jaegermann, W. A1 - Toupance, T. A1 - Shmeliov, A. A1 - Nicolosi, V. A1 - Heuzé, K. A1 - Mandel, K. A1 - Dembski, S. T1 - Discovering the determining parameters for the photocatalytic activity of TiO2 colloids based on an anomalous dependence on the specific surface area N2 - The photocatalytic (PC) performance of titanium dioxide (TiO2) nanoparticles strongly depends on their specific surface, the presence of crystal defects, their crystal phase, and the exposed crystal facets. In order to understand which of these factors contributes most significantly to the PC activity of TiO2 colloids, all of them have to be individually analyzed. This study entails the synthesis of five anatase nanocrystal samples. By maintaining the same reactant ratios as well as hydrothermal sol–gel synthesis route and only varying the autoclaving time or temperature, different crystallite sizes are obtained under comparable experimental conditions. A decrease in PC performance with increase in specific surface area is found. Such an unexpected counterintuitive result establishes the basis for a better understanding of the crucial factors that ultimately determine the PC activity. These are investigated by studying nanocrystals bulk and surface structure and morphology using a selection of complementary analysis methods (X-ray photoelectron spectroscopy (XPS), X-ray absorption fine structure (XAFS), X-ray diffraction (XRD)…). It is found that a change in the nanocrystal morphology from an equilibrium state truncated tetragonal bipyramid to a more elongated rod-like structure accompanied by an increase in oxygen vacancies is responsible for an augmented PC activity of the TiO2 nanocrystals. KW - Ti-based colloids KW - Photocatalysis KW - Spectroscopy KW - XAFS PY - 2018 DO - https://doi.org/10.1002/ppsc.201800216 SN - 0934-0866 SN - 1521-4117 VL - 35 IS - 9 SP - 1800216, 1 EP - 10 PB - Wiley Online Library AN - OPUS4-46068 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - INPR A1 - Liu, Yanchen A1 - de Oliveira Guilherme Buzanich, Ana A1 - Alippi, Paola A1 - Lee, Kug-Seung A1 - Jeon, Taeyeol A1 - Weißer, Kilian A1 - Karlsen, Martin A. A1 - Russo, Patrícia A. A1 - Pinna, Nicola T1 - FeNb2O6 as a high-performance anode for sodium-ion batteries enabled by structural amorphization coupled with NbO6 local ordering. N2 - Pseudocapacitance-type transition metal oxides have been extensively investigated as anodes materials for lithium-ion batteries. Currently, they are also emerging as promising anodes for sodium-ion batteries due to their low volume change and safety. However, the potential electrochemical performance in sodium energy storage is not fully achieved, primarily due to the larger radius of the Na+-ions. Here, we report for the first time an iron niobate with columbite structure as a high-performance sodium storage anode. The presence of iron in the structure is vital to trigger the loss of long-range order through disorder of the FeO6 octahedra local structure, subsequently allowing reversible Na storage in an amorphous phase. Simultaneously, the formation of short-range ordered zigzag-chain structures within the NbO6 planes creates a “skeleton” that offers abundant active sites for pseudocapacitive ion storage and enhanced ion diffusion pathways. These characteristics of FeNb2O6 make it an effective intercalation host, offering high capacity along with fast Na+ insertion and extraction, as demonstrated through operando and ex-situ characterizations. It leads to an applicable reversible capacity ( 300 mAh g-1) with a favorable average voltage of ca. 0.6 V and excellent rate capability (180.4 mAh g-1 at a current density of 2 A g-1). This study provides insights into the development of intrinsically active transition metal oxides for Na+-ion intercalation. KW - XAS KW - Sodium-Ion-Batteries KW - In-situ PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-631159 DO - https://doi.org/10.26434/chemrxiv-2025-2gn7z SP - 1 EP - 51 PB - American Chemical Society (ACS) AN - OPUS4-63115 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - 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 - JOUR A1 - Rauwolf, M. A1 - Turyanskaya, A. A1 - Roschger, A. A1 - Prost, J. A1 - Simon, R. A1 - Scharf, O. A1 - Radtke, Martin A1 - Schoonjans, Tom A1 - de Oliveira Guilherme Buzanich, Ana A1 - Klaushofer, K. A1 - Wobrauschek, P. A1 - Hofstaetter, J. G. A1 - Roschger, P. A1 - Streli, C. T1 - Synchrotron radiation micro X-ray fluorescence spectroscopy of thin structures in bone samples: comparison of confocal and color X-ray camera setups N2 - In the quest for finding the ideal synchrotron-radiation-induced imaging method for the investigation of trace element distributions in human bone samples, experiments were performed using both a scanning confocal synchrotron radiation micro X-ray fluorescence (SR-mXRF) (FLUO beamline at ANKA) setup and a full-field color X-ray camera (BAMline at BESSY-II) setup. As zinc is a trace element of special interest in bone, the setups were optimized for its detection. The setups were compared with respect to count rate, required measurement time and spatial resolution. It was demonstrated that the ideal method depends on the element of interest. Although for Ca (a major constituent of the bone with a low energy of 3.69 keV for its K alpha XRF line) the color X-ray camera provided a higher resolution in the plane, for Zn (a trace element in bone) only the confocal SR-µXRF setup was able to sufficiently image the distribution. KW - Synchrotron KW - BAMline KW - BESSY KW - XRF KW - X-ray Color Camera PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-391944 DO - https://doi.org/10.1107/S1600577516017057 SN - 1600-5775 VL - 24 SP - 307 EP - 311 PB - International Union of Crystallography AN - OPUS4-39194 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 - Liu, Yanchen A1 - de Oliveira Guilherme Buzanich, Ana A1 - Montoro, Luciano A. A1 - Liu, Hao A1 - Liu, Ye A1 - Emmerling, Franziska A1 - Russo, Patrícia A. A1 - Pinna, Nicola T1 - A partially disordered crystallographic shear block structure as fast-charging negative electrode material for lithium-ion batteries N2 - A well-ordered crystalline structure is crucial in battery electrodes, as the dimensionality and connectivity of the interstitial sites inherently influence Li+ ions diffusion kinetics. Niobium tungsten oxides block structures, composed of ReO3-type blocks of specific sizes with well-defined metal sites, are promising fast-charging negative electrode materials. Structural disorder is generally detrimental to conductivity or ion transport. However, here, we report an anomalous partially disordered Nb12WO33 structure that significantly enhances Li-ion storage performance compared to the known monoclinic Nb12WO33 phase. The partially disordered phase consists of corner-shared NbO6 octahedra blocks of varied sizes, including 5×4, 4×4, and 4×3, with a disordered arrangement of distorted WO4 tetrahedra at the corners of the blocks. This structural arrangement is robust during lithiation/delithiation, exhibiting minor local structure changes during cycling. It enables accelerated Li-ion migration, resulting in promising fast-charging performance, namely, 62.5 % and 44.7 % capacity retention at 20 C and 80 C, respectively. This study highlights the benefits of introducing disorder into niobium tungsten oxide shear structures, through the establishment of clear structure-performance correlations, offering guidelines for designing materials with targeted properties. KW - Lithium ion batteries KW - Oxides KW - XANES KW - XRD PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-637994 DO - https://doi.org/10.1038/s41467-025-61646-9 SN - 2041-1723 VL - 16 IS - 1 SP - 1 EP - 15 PB - Springer Science and Business Media LLC AN - OPUS4-63799 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Guilherme, A. A1 - Buzanich, Günter A1 - Carvalho, M.L. T1 - Focusing systems for the generation of X-ray micro beam: An overview N2 - This manuscript reviews the most used optical systems for X-ray microprobes and summarizes the experiences in research with synchrotron radiation as well as with X-ray tube generators. The need for smaller beam spot sizes for various applications and the unique properties of X-rays have induced a remarkable and fast development in X-ray optical systems. These systems are divided into three main categories: diffractive, reflective and refractive. Examples of the three will be covered in this paper, highlighting the properties that allow having spot sizes down to sub-micrometer regime. However, the extraordinary capabilities of such systems are always relative. Therefore, an overview of the techniques that use such optical systems will be given, emphasizing their applicability on several case studies. KW - X-ray optic KW - K–B mirror KW - Capillary KW - Compound refractive lens KW - Fresnel zone plate PY - 2012 DO - https://doi.org/10.1016/j.sab.2012.07.021 SN - 0584-8547 SN - 0038-6987 VL - 77 SP - 1 EP - 8 PB - Elsevier CY - Amsterdam AN - OPUS4-27722 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Guilherme, A. A1 - Hodoroaba, Vasile-Dan A1 - Benemann, Sigrid A1 - Coroado, J. A1 - Carvalho, M.L. T1 - Morphological and compositional features of portuguese polychrome glazed pottery investigated by SEM/EDX - hints about the manufacturing processes N2 - The study addresses to the morphological and compositional Features of polychrome glazed ceramic samples from Portugal by means of a SEM/EDX System (scanning electron microscopy with energy-dispersive X-ray spectroscopy). KW - SEM/EDX KW - Portuguese polychrome glazed pottery KW - Manufacturing KW - Morphology KW - Composition PY - 2013 DO - https://doi.org/10.1017/S1431927613009148 SN - 1431-9276 SN - 1435-8115 VL - 19 IS - Suppl. 2 SP - 1430 EP - 1431 PB - Cambridge University Press CY - New York, NY AN - OPUS4-29422 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Guilherme, A. A1 - Hodoroaba, Vasile-Dan A1 - Benemann, Sigrid A1 - Coroado, J. A1 - Carvalho, M.L. T1 - Morphological and compositional features of blue and yellow pigments used in Portuguese glazed ceramics by SEM/EDX - unravelling manufacturing differences N2 - Morphological and compositional features regarding blue and yellow pigments used in glazed ceramics from Portugal are investigated by means of a SEM/EDX system. Fragments of samples produced in the main pottery-making centres between the XVI–XVIII centuries (Lisbon and Coimbra) were the objects of study. The main question to be answered is whether there are differences in the manufacturing procedures employed. For this purpose, two types of samples were analysed: faiences and wall-tiles (the famous 'Azulejos', in Portuguese). Differences between the manufacturing techniques of the two production centres were veritably found. The expected linkage between Fe–Co–Ni–As–Bi was challenging to investigate. Thus, Co was found in Fe- or Ni-rich structures, but with no structural connection to As or Bi. However, the As-needle-like structures were always identified in blue regions. One interesting finding related particularly to the blue pigment was the presence of SnO2 agglomerates throughout the whole glaze, which suggests its intentional addition for 'lightening' the well known dark Co blue. Concerning the yellow pigment differences established in the crystal shape and size are indicative of different firing temperatures used. KW - Scanning electron microscope (SEM) KW - Energy dispersive X-ray spectroscopy (EDX) KW - Portuguese glazed ceramics KW - Coimbra KW - Lisbon KW - Blue pigment KW - Yellow pigment KW - Morphology KW - Elemental composition KW - Firing temperature PY - 2014 DO - https://doi.org/10.1039/c3ja50268f SN - 0267-9477 SN - 1364-5544 VL - 29 IS - 1 SP - 51 EP - 57 PB - Royal Society of Chemistry CY - London AN - OPUS4-29722 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Guilherme, A. A1 - Buzanich, Günter A1 - Radtke, Martin A1 - Reinholz, Uwe A1 - Coroado, J. A1 - Dos Santos, J.M.F. A1 - Carvalho, M.L. T1 - Synchrotron micro-XRF with compound refractive lenses (CRLs) for tracing key elements on Portuguese glazed ceramics N2 - Several glazed ceramic fragments (XVIth to XVIIIth centuries) from two production centers in Portugal (Coimbra and Lisbon) were the object of this study. The ones from Coimbra comprise two sets of samples: faiences and tiles. The ones from Lisbon are only tiles (azulejos, in Portuguese). The three main divisions of such pieces are the ceramic support (body), glaze and surface decoration. The system decoration/glaze is not easy to investigate, due to the high heterogeneity resulting from the mixing procedures and firing temperatures used. Moreover, the ability of the pigment to diffuse into the base glaze varies depending on the composition of both the pigment and the glaze in terms of fusibility. In order to raster these effects, high resolution techniques are required. In this work, synchrotron micro-X-ray fluorescence (µ-XRF) analysis was performed to monitor the profiles of the characteristic elements from the colors used and the glaze in well prepared cross-sections of the samples. Key elements are: Co for blue, Mn for purple, Cu for green, Sb for yellow, Pb for the glaze and Fe for the body. The major difference observed is that faiences have glaze thicknesses between 150 and 200 µm and tiles have glaze thicknesses between 350 and 400 µm. Furthermore, in faiences all the pigments except the yellow ones are well dispersed into the glassy matrix, while in tiles, all of them are just partially diffused throughout the glaze. However, differences between the tiles from Coimbra and Lisbon were observed. In the samples from Lisbon, a higher intake from the pigment throughout the glaze is observed. KW - Synchrotron micro-XRF KW - Compound refractive lenses (CRLs) KW - Portuguese glazed ceramics PY - 2012 DO - https://doi.org/10.1039/c2ja30030c SN - 0267-9477 SN - 1364-5544 VL - 27 IS - 6 SP - 966 EP - 974 PB - Royal Society of Chemistry CY - London AN - OPUS4-26789 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Brieger, C. A1 - Melke, J. A1 - van der Bosch, N. A1 - Reinholz, Uwe A1 - Riesemeier, Heinrich A1 - de Oliveira Guilherme Buzanich, Ana A1 - Krishna Kayarkatte, M. A1 - Derr, I. A1 - Schökel, A. A1 - Roth, C. ED - de Oliveira Guilherme Buzanich, Ana T1 - A combined in-situ XAS–DRIFTS study unraveling adsorbate induced changes on Pt nanoparticle structure N2 - The adsorption behavior of Platinum nanoparticles was studied for the as-received catalyst (under inert gas), under hydrogen and CO atmosphere using our newly designed in-situ cell. X-ray Absorption Spectroscopy (XAS) and Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) experiments were performed simultaneously with high data quality. Structural information and the type of adsorbate could be revealed via Extended X-ray Absorption Fine Structure (EXAFS) analysis, Δμ X-ray Absorption Near Edge Structure analysis (Δμ XANES) and in-situ DRIFTS. The as-received catalyst showed sub-surface oxygen and O(n-fold). Under CO atmosphere only CO(atop) was found. Reversible adsorbate induced changes of the Pt nanoparticle structure were derived from changes in the Pt-Pt coordination number and the corresponding bond distance. Under reducing conditions (H2, CO) a significant increase in both values occurred. Temperature dependent desorption of CO revealed a gradual shift from Pt-CO to Pt-O. Reoxidation was clearly assigned to strong metal support interaction from the SiO2 support. KW - X-ray absorption spectroscopy KW - DRIFTS KW - XANES KW - CO adsoprtion KW - Platinum KW - String metal support interaction KW - Silica support KW - Adsorbates KW - Infrared spectroscopy PY - 2016 DO - https://doi.org/10.1016/j.jcat.2016.03.034 SN - 0021-9517 VL - 339 SP - 57 EP - 67 PB - Elsevier AN - OPUS4-38367 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lutz, C. A1 - Hampel, S. A1 - Beuermann, S. A1 - Turek, T. A1 - Kunz, U. A1 - de Oliveira Guilherme Buzanich, Ana A1 - Radtke, Martin A1 - Fittschen, U. E. A. T1 - Investigation on Vanadium Species Distribution in Nafion™ 117 after Cyclization in a Vanadium Redox Flow Battery N2 - The vanadium redox flow battery (VRFB) is currently a potential candidate for stationary energy storage. A major challenge is the unintended vanadium transport through the separator, which results in a fade of capacity. To overcome this issue, it is necessary to understand the transport processes in the membrane on a more fundamental level. In this work, the vanadium species distribution in Nafion™ 117 after cyclization was investigated. Two membranes, one from a charged VRFB and another from a discharged VRFB, were analyzed using ultraviolet–visible spectroscopy (UV/VIS) and X-ray absorption near edge structure spectroscopy (XANES). Little difference between the two membranes was recognizable according to the UV/VIS results. In comparison, the XANES results showed that the membrane from the charged VRFB contains more V3+ than VO2+, whereas for the discharged case, more VO2+ is present in the membrane. KW - Synchrotron KW - BAMline KW - XANES KW - Vanadium redox flow battery PY - 2021 VL - 64 SP - 1 EP - 8 AN - OPUS4-54144 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Guilherme, A. T1 - SR.-XANES for the Study of Portuguese Polychrome Glazed Ceramics: 16th - 19th centuries T2 - TECHNART 2011, Non-destructive and microanalytical techniques in art and cultural heritage CY - Berlin, Germany DA - 2011-04-26 PY - 2011 AN - OPUS4-24148 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lin, R. A1 - Li, X. A1 - Krajnc, A. A1 - Li, Z. A1 - Li, M. A1 - Wang, W. A1 - Zhuang, L. A1 - Smart, S. A1 - Zhu, Z. A1 - Appadoo, D. A1 - Harmer, J. R. A1 - Wang, Z. A1 - de Oliveira Guilherme Buzanich, Ana A1 - Beyer, S. A1 - Wang, L. A1 - Mali, G. A1 - Bennett, T. D. A1 - Chen, V. A1 - Hou, J. T1 - Mechanochemically Synthesised Flexible Electrodes Based on Bimetallic Metal–Organic Framework Glasses for the Oxygen Evolution Reaction N2 - The melting behaviour of metal–organic frameworks (MOFs) has aroused significant research interest in the areas of materials science, condensed matter physics and chemical engineering. This work first introduces a novel method to fabricate a bimetallic MOF glass, through meltquenching of the cobalt-based zeolitic imidazolate Framework (ZIF) [ZIF-62(Co)] with an adsorbed ferric coordination complex. The high-temperature chemically reactive ZIF-62-(Co) liquid facilitates the formation of coordinative bonds between Fe and imidazolate ligands, incorporating Fe nodes into the framework after quenching. The resultant Co–Fe bimetallic MOF glass therefore shows a significantly enhanced oxygen evolution reaction performance. The novel bimetallic MOF glass, when combined with the facile and scalable mechanochemical synthesis technique for both discrete powders and surface coatings on flexible substrates, enables significant opportunities for catalytic device Assembly KW - Electrodes KW - MOF KW - OER KW - XANES KW - XAS KW - Bimetallic frameworks PY - 2022 DO - https://doi.org/10.1002/anie.202112880 VL - 61 IS - 4 SP - e202112880 PB - Wiley AN - OPUS4-54018 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Qureshi, Navid A1 - Morrow, Ryan A1 - Eltoukhy, Samar A1 - Grinenko, Vadim A1 - de Oliveira Guilherme Buzanich, Ana A1 - Onykiienko, Yevhen A. A1 - Kulbakov, Anton A1 - Inosov, Dmytro S. A1 - Adler, Peter A1 - Valldor, Martin T1 - Noncollinear Magnetic Structures in the Chiral Antiperovskite β-Fe2SeO N2 - We present the magnetic properties of the chiral, polar, andpossibly magnetoelectric antiperovskite β-Fe2SeO as derived from magnet-ization and specific-heat measurements as well as from powder neutrondiffraction and Mössbauer experiments. Our macroscopic data unambig-uously reveal two magnetic phase transitions at TN1 ≈ 103 K and TN2 ≈ 78K, while Rietveld analysis of neutron powder diffraction data reveals anoncollinear antiferromagnetic structure featuring magnetic moments inthe a−b plane of the trigonal structure and a ferromagnetic moment alongc. The latter is allowed by symmetry between TN1 and TN2, weakly visible inthe magnetization data yet unresolvable microscopically. While theintermediate phase can be expressed in the trigonal magnetic spacegroup P31, the magnetic ground state is modulated by a propagation vectorq = (1/2 1/2 0) resulting in triclinic symmetry and an even more complexlow-temperature spin arrangement which is also reflected in the Mö ssbauer hyperfine patterns indicating additional splitting of Fesites below TN2. The complex noncollinear spin arrangements suggest interesting magnetoelectric properties of this polar magnet. KW - EXAFS KW - Antiperovskite KW - Magnetic structure PY - 2024 DO - https://doi.org/10.1021/acs.inorgchem.4c02916 SN - 0020-1669 VL - 63 IS - 48 SP - 22712 EP - 22720 PB - American Chemical Society (ACS) AN - OPUS4-63116 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Guilherme, A. T1 - Synchroton Micro-XRF with Compound Refractive Lenses (CRLs) for tracing key elements on Portuguese glazed ceramics T2 - 14th International Workshop on Radiation Imaging Detectors CY - Figueira da Foz, Portugal DA - 2012-07-01 PY - 2012 AN - OPUS4-27190 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zhang, Rui A1 - Russo, Patrícia A. A1 - de Oliveira Guilherme Buzanich, Ana A1 - Jeon, Taeyeol A1 - Pinna, Nicola T1 - Hybrid organic–inorganic transition-metal phosphonates as precursors for water oxidation electrocatalysts N2 - Efficient water oxidation catalysts are required for the development of water splitting technologies. Herein, the synthesis of layered hybrid NiFephenylphosphonate compounds from metal acetylacetonate precursors and phenylphosphonic acid in benzyl alcohol, and their Oxygen evolution reaction performance in alkaline medium, are reported. The hybrid particles are formed by inorganic layers of NiO6 and FeO6 distorted octahedra separated by bilayers of the organic group, and template the Formation in situ of NiFe hydroxide nanosheets of sizes between 5 and 25 nm and thicknesses between 3 and 10 nm. X-ray absorption spectroscopy measurements suggest that the hybrid also acts as a template for the local structure of the metal sites in the active catalyst, which remain distorted after the transformation. Optimum electrocatalytic activity is achieved with the hybrid compound with a Fe content of 16%. The combination of the synergistic effect between Ni and Fe with the structural properties of the hybrid results in an efficient catalyst that generates a current density of 10 mA cm−2 at an overpotential of 240 mV, and also in a stable catalyst that operates continuously at low overpotentials for 160 h. KW - Water oxydation catalysis KW - EXAFS PY - 2017 DO - https://doi.org/10.1002/adfm.201703158 SN - 1616-301X SN - 1616-3028 VL - 27 IS - 40 SP - Article 1703158, 1 EP - 11 PB - WILEY-VCH Verlag CY - Weinheim AN - OPUS4-42783 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pessanha, Sofia A1 - Fortes, António A1 - Lopes, Marta B. A1 - de Oliveira Guilherme Buzanich, Ana A1 - Ortega-Feliu, Inés A1 - Respaldiza, Miguel A. A1 - Gomez Tubio, Blanca A1 - Makarova, Anna A1 - Smirnov, Dmitry A1 - Kumar, Sourabh A1 - Mata, António A1 - Silveira, João T1 - Multi-technique computational assessment of fluoride uptake in enamel using PIGE, NEXAFS, and Raman spectroscopy N2 - This study explores F incorporation in enamel via PIGE, NEXAFS, and Raman spectroscopy, integrating experimental/simulated spectra. Machine Learning boosts data interpretation, offering key insights into F delivery for clinical application. KW - Simulations KW - Enamel KW - Fuorine KW - NEXAFS PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-631138 DO - https://doi.org/10.1039/D5TB00213C SN - 2050-750X SP - 1 EP - 10 PB - Royal Society of Chemistry (RSC) AN - OPUS4-63113 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Guilherme, A. T1 - SR-Xanes for the study of portuguese polychrome glazed ceramics: 16th - 19th centuries T2 - Technart 2011 CY - Berlin, Germany DA - 2011-04-26 PY - 2011 AN - OPUS4-23083 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hachmöller, O. A1 - de Oliveira Guilherme Buzanich, Ana A1 - Aichler, M. A1 - Radtke, Martin A1 - Dietrich, D. A1 - Schwamborn, K. A1 - Lutz, L. A1 - Werner, M. A1 - Sperling, M. A1 - Walch, A. A1 - Karst, U. T1 - Elemental bioimaging and speciation analysis for the investigation of Wilsons disease using μXRF and XANES N2 - A liver biopsy specimen from a Wilson’s disease (WD) patient was analyzed by means of micro-X-ray fluorescence (mXRF) spectroscopy to determine the elemental distribution. First, bench-top mXRF was utilized for a coarse scan of the sample under laboratory conditions. The resulting distribution maps of copper and iron enabled the determination of a region of interest (ROI) for further analysis. In order to obtain more detailed elemental information, this ROI was analyzed by synchrotron radiation (SR)-based mXRF with a beam size of 4 mm offering a resolution at the cellular level. Distribution maps of additional elements to copper and iron like zinc and manganese were obtained due to a higher sensitivity of SR-mXRF. In addition to this, X-ray absorption near edge structure spectroscopy (XANES) was performed to identify the oxidation states of copper in WD. This speciation analysis indicated a mixture of copper(I) and copper(II) within the WD liver tissue. KW - progressive hepatolenticular degeneration KW - mXRF Micro-X-ray fluorescence spectroscopy KW - XANES X-ray absorption near edge structure spectroscopy PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-360811 DO - https://doi.org/10.1039/C6MT00001K SN - 1756-5901 SN - 1756-591X PB - Royal Society of Chemistry CY - Cambridge AN - OPUS4-36081 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -