TY - JOUR
A1 - Aliyah, K.
A1 - Berger, A.
A1 - Lazaridis, T.
A1 - Appel, C.
A1 - Prehal, C.
A1 - Menzel, A.
A1 - Guizar-Sicairos, M.
A1 - Smales, Glen J.
A1 - Pauw, Brian Richard
A1 - Gasteiger, H. A.
A1 - Gubler, L.
A1 - Büchi, F. N.
A1 - Eller, J.
T1 - Impact of Microporous Layer Composition on the Water Content in the Membrane Electrode Assembly of Polymer Electrolyte Fuel Cells
N2 - Polymer electrolyte fuel cells are paramount for future emission-free mobility. One of the vital challenges for prospering commercialization of PEFCs is water management in the cells. A microporous layer (MPL) is typically positioned between the gas Diffusion layer (GDL) and the catalyst layer (CL) to boost the cell performance and facilitate water management. In this study, three different MPLs were investigated, namely, carbon black-based MPLs with different PTFE binder contents (20 wt % PTFE as a base case and 40 wt % PTFE), as well as perforated MPLs with micron-sized pores coated on the same GDL- Substrate (Freudenberg H14). The water content in the membrane, catalyst layers (CL), and MPLs was explored using operando scanning small- and wide-angle X-ray scattering (S/WAXS). At Tcell = 80 °C, relative humidity = 100%, pabs = 3 bar, the MPL with larger pores exhibits slightly higher performance than the base case, while a considerably lower cathode CL and MPL saturation levels were observed for the MPL. In contrast, the MPL with higher amounts of PTFE binder shows lower performance than the base case, with considerably higher cathode CL and MPL saturation levels. 3D representations of how the pores could be filled in the cathode CLs were obtained from operando SAXS profiles using representative structure modeling for the different materials and operating conditions.
KW - Polymer electrolyte fuel cell
KW - Catalyst layer saturation
KW - Microporous layer saturation
KW - Membrane hydration
KW - Small and wide-angle scattering
KW - MOUSE
KW - SAXS
KW - X-ray scattering
KW - Energy storage materials
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656691
DO - https://doi.org/10.1021/acsami.5c22540
SN - 1944-8244
SP - 1
EP - 17
PB - American Chemical Society (ACS)
AN - OPUS4-65669
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - El Abbassi, Abdelouahad
A1 - Krenzer, Julius
A1 - Petrov, Eugene P.
A1 - Biesen, Lukas
A1 - Vasylyeva, Vera
A1 - Merzenich, Sarah
A1 - Resch-Genger, Ute
A1 - Müller, Thomas J. J.
T1 - Aroyl-S,N-ketene acetal-triarylamine bichromophores – intramolecular energy transfer and dual emission upon induced aggregation and encapsulation
N2 - Aroyl-S,N-ketene acetal-based bichromophores are synthesized by a catalytic aryl amination and their photophysics are studied in the solid state, in ethanol–water mixtures inducing aggregation, and after encapsulation in polystyrene nanoparticles. The dye substitution pattern controls aggregation-induced emission and intramolecular energy transfer efficiency, resulting in single-band or dual fluorescence and a strong increase in fluorescence quantum yield upon particle encapsulation.
KW - Fluorescence
KW - Dye
KW - Aggregation
KW - Photophysics
KW - Enhancement
KW - White light emission
KW - Energy transfer
KW - Quantum yield
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656700
DO - https://doi.org/10.1039/d5ra09361a
SN - 2046-2069
VL - 16
IS - 11
SP - 10255
EP - 10260
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-65670
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Saeed, A. M.
A1 - Saied, M. A.
A1 - Szymoniak, Paulina
A1 - Altmann, Korinna
A1 - Schönhals, Andreas
A1 - Fahmy, Alaa
T1 - High performance novel polyelectrolyte membrane consisting of polyvinyl alcohol-phenylsilanol-polypyrrole
N2 - The synthesis of composite membranes based on PVA, PPy, and sulfonated–hydrolyzed TMPS was investigated for application in proton–exchange membrane fuel cells. FT–IR confirmed the hydrolysis of TMPS through the appearance of Si–OH vibrations, disappearance of Si–O–CH3 bands, reduced CH3 stretching intensity (2840 cm− 1), and successful sulfonation of the phenyl ring (1030 cm− 1). XPS verified the introduction of sulfonic acid groups by identifying S2p peaks between 166–170 eV. Scanning electron microscopy (SEM) showed an incorporation of PPy and that the membrane morphology altered by silanol leading to an increased surface roughness and inducing phase separation in comparison to pure PVA. The PVA–PPy–Si membrane which did not undergo phase separation demonstrated improved mechanical stability (maximum stress 5.91 MPa), reduced methanol uptake (22%, lower than Nafion’s 30%), and enhanced thermal resistance compared to PVA–PPy and PVA–Si. It also exhibited a high ion–exchange capacity (1.5mmol g− 1, exceeding Nafion® at 0.9mmol g− 1 ) and a proton conductivity of 0.036 S/cm, twice that of Nafion 117. These combined properties identify the PVA–PPy–Si composite as a promising high–performance polyelectrolyte membrane for fuel cell applications.
KW - Polyelectrolyte membrane
PY - 2026
DO - https://doi.org/10.1016/j.apsusc.2026.166495
SN - 1873-5584
VL - 731
SP - 1
EP - 11
PB - Elsevier B.V.
AN - OPUS4-65627
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fayis Kalady, Mohammed
A1 - Schultz, Johannes
A1 - Weinel, Kristina
A1 - Wolf, Daniel
A1 - Lubk, Axel
T1 - Geometry-dependent localization of surface plasmons on random gold nanoparticle assemblies
N2 - Assemblies of plasmonic nanoparticles (NPs) support hybridized modes of localized surface plasmons (LSPs), which delocalize in geometrically well-ordered arrangements. Here, the hybridization behavior of LSPs in geometrically completely disordered two-dimensional arrangements of Au NPs fabricated by an e-beam synthesis method is studied. Employing electron energy loss spectroscopy in a scanning transmission electron microscope and numerical simulations, the disorder-driven spatial and spectral localization of the coupled LSP modes that depends on the NP thickness is revealed. Below a NP thickness of 0.4 nm, localization increases toward higher hybridized LSP mode energies. In comparison, above 10 nm thickness, a decrease of localization toward higher mode energies is observed. In the intermediate thickness regime, a transition of the energy dependence of the localization between the two limiting cases, exhibiting a mode energy with minimal localization, is observed. It is shown that this behavior is mainly driven by the energy and thickness dependence of the polarizability of the individual NPs.
KW - Gold Nanoparticles
KW - Surface plasmons
KW - Electron enerdy loss spectroscopy (EELS)
KW - scanning transmission electron microscopy
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-647230
DO - https://doi.org/10.1103/44nk-6bp2
SN - 2643-1564
VL - 7
IS - 043053
EP - 4
PB - American Physical Society
AN - OPUS4-64723
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pütz, E.
A1 - Smales, Glen Jacob
A1 - Jegel, O.
A1 - Emmerling, Franziska
A1 - Tremel, W.
T1 - Tuning ceria catalysts in aqueous media at the nanoscale: how do surface charge and surface defects determine peroxidase- and haloperoxidase-like reactivity
N2 - Designing the shape and size of catalyst particles, and their interfacial charge, at the nanometer scale can radically change their performance. We demonstrate this with ceria nanoparticles. In aqueous media, nanoceria is a functional mimic of haloperoxidases, a group of enzymes that oxidize organic substrates, or of peroxidases that can degrade reactive oxygen species (ROS) such as H2O2 by oxidizing an organic substrate. We show that the chemical activity of CeO2−x nanoparticles in haloperoxidase- and peroxidaselike reactions scales with their active surface area, their surface charge, given by the ζ-potential, and their surface defects (via the Ce3+/Ce4+ ratio). Haloperoxidase-like reactions are controlled through the ζ-potential as they involve the adsorption of charged halide anions to the CeO2 surface, whereas peroxidase-like reactions without charged substrates are controlled through the specific surface area SBET. Mesoporous CeO2−x particles, with large surface areas, were prepared via template-free hydrothermal reactions and characterized by small-angle X-ray scattering. Surface area, ζ-potential and the Ce3+/Ce4+ ratio are controlled in a simple and predictable manner by the synthesis time of the hydrothermal reaction as demonstrated by X-ray photoelectron spectroscopy, sorption and ζ-potential measurements. The surface area increased with synthesis time, whilst the Ce3+/Ce4+ ratio scales inversely with decreasing ζ-potential. In this way the catalytic activity of mesoporous CeO2−x particles could be tailored selectively for haloperoxidase- and peroxidase-like reactions. The ease of tuning the surface properties of mesoporous CeO2x particles by varying the synthesis time makes the synthesis a powerful general tool for the preparation of nanocatalysts according to individual needs.
KW - SAXS
KW - Ceria
KW - Zeta potential
PY - 2022
DO - https://doi.org/10.1039/D2NR03172H
SP - 1
EP - 12
PB - Royal Society of Chemistry
AN - OPUS4-55649
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bustamante, Joana
A1 - Ghata, Anupama
A1 - Naik, Aakash A.
A1 - Ertural, Christina
A1 - Ueltzen, Katharina
A1 - Zeier, Wolfgang G.
A1 - George, Janine
T1 - Thermal transport in Ag8T S6(T = Si, Ge, Sn) argyrodites: an integrated experimental, quantum-chemical, and computational modelling study
N2 - Argyrodite-type Ag-based sulfides combine exceptionally low lattice thermal and high ionic conductivity, making them promising candidates for thermoelectric and solid-state energy applications. In this work, we studied Ag8TS6 (T = Si, Ge, Sn) argyrodite family by combining chemical-bonding analysis, lattice vibrational properties simulation, and experimental measurements to investigate their structural and thermal transport properties. Furthermore, we propose a two-channel lattice-dynamics model based on Grüneisen-derived phonon lifetimes and compare it to an approach using machine-learned interatomic potentials. Both approaches are able to predict thermal conductivity in agreement with experimental lattice thermal conductivities along the whole temperature range, highlighting their potential suitability for future high-throughput predictions. Our findings also reveal a relationship between bond heterogeneity arising from weakly bonded Ag+ ions and occupied antibonding states in Ag–S and Ag–Ag interactions and strong anharmonicity, including large Grüneisen parameters, and low sound velocities, which are responsible for the low lattice thermal conductivity of Ag8SnS6, Ag8GeS6, and Ag8SiS6. We furthermore show that thermal and ionic conductivities in all three compounds are independent of each other and can likely be tuned individually.
KW - Thermal Conductivity
KW - Ionic Conductivity
KW - Machine Learning
KW - Materials Design
KW - Microstructure
KW - Bonding Analysis
KW - Anharmonicity
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-657076
DO - https://doi.org/10.1039/D5TA08709K
SN - 2050-7488
SP - 1
EP - 13
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-65707
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Miyata, Ayana
A1 - Tokuda, Shun
A1 - Kuzumoto, Mako
A1 - Lee, Guan-Sian
A1 - Yamashita, Masataka
A1 - Nishiguchi, Taichi
A1 - Negoro, Masaki
A1 - Pauw, Brian Richard
A1 - Chan, Yi-Tsu
A1 - Kanamori, Kazuyoshi
A1 - Urayama, Kenji
A1 - Sugimoto, Kunihisa
A1 - Furukawa, Shuhei
T1 - One-Dimensional van der Waals Porous Fibrils Assembled from Metal–Organic Polyhedra
N2 - Supramolecular systems exhibit collective functions that emerge from the hierarchical assembly of individual molecular building blocks. Metal−organic polyhedra (MOPs) are a class of functional supramolecular architectures with well-defined molecular geometry and an intrinsic cavity. In recent years, considerable progress has been made in assembling MOPs into extended networks to create porous solids. However, most reported MOP assemblies are limited to three-dimensional networks, which, owing to their high-dimensional connectivity, hinder effective stress dissipation and render them brittle under mechanical stress.
Here, we report the one-dimensional (1D) self-assembly of MOPs into supramolecular polymeric aerogels that combine permanent microporosity with exceptional mechanical flexibility. The reaction between amino acid-functionalized naphthalenediimide (NDI) linkers and copper salts led to the synthesis of octahedral copper-based MOPs, followed by their spontaneous self-assembly to form supramolecular gels. The corresponding aerogels converted from the gels possessed uniform 1D fibrillar networks (14.8 ± 2.2 nm in width) with intrinsic microporosity derived from individual MOP cavities. The aerogel endured 87% compressive strain without fracture, demonstrating distinct ductility. Furthermore, these fibrils in the supramolecular gels were converted to crystals after 2 weeks. Single-crystal X-ray diffraction revealed that MOPs are arranged via face-to-face interaction between octahedral MOPs to form a 1D helical chain structure. An analysis of the self-assembly process using Hansen solubility parameters unveiled that solvent conditions with high polarity and low dispersion interaction drive the formation of anisotropic assemblies. This work provides a new strategy for tailoring the mechanical properties of supramolecular materials through dimensional control of their assemblies.
KW - Aerogels
KW - Crystals
KW - Metal organic frameworks
KW - Nanofibers
KW - Solvents
KW - X-ray scattering
KW - SAXS
KW - Nanostructure
KW - Small-angle X-ray scattering
PY - 2026
DO - https://doi.org/10.1021/jacs.5c21654
SN - 0002-7863
SP - 1
EP - 13
PB - American Chemical Society (ACS)
AN - OPUS4-65776
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -