A5087164870- Nanoporous metals and alloys
- Electrocatalysts for Energy Conversion
- Electron and X-Ray Spectroscopy Techniques
- Advanced Electron Microscopy Techniques and Applications
- Catalytic Processes in Materials Science
- Nanocluster Synthesis and Applications
- Force Microscopy Techniques and Applications
- Integrated Circuits and Semiconductor Failure Analysis
- Electronic and Structural Properties of Oxides
- Advanced X-ray Imaging Techniques
- Electrostatics and Colloid Interactions
- Anodic Oxide Films and Nanostructures
- Nanomaterials for catalytic reactions
- Electrochemical Analysis and Applications
- Spectroscopy and Chemometric Analyses
- Supercapacitor Materials and Fabrication
- GaN-based semiconductor devices and materials
- ZnO doping and properties
- Machine Learning in Materials Science
- Water Quality Monitoring and Analysis
- Material Dynamics and Properties
- Copper-based nanomaterials and applications
- Enhanced Oil Recovery Techniques
- Coagulation and Flocculation Studies
- Economic and Social Issues
University of Bremen
2015-2024
Staats- und Universitätsbibliothek Bremen
2023
Georgi Nadjakov Institute of Solid State Physics
2022
University of Antwerp
2019
Christophorus Kliniken
2015
Abstract Formation of hetero‐contacts between particles different materials in nanoparticle hetero‐aggregates can lead to new functional properties. Improvement the behavior requires a detailed characterization mixing two types particles, order correlate with performance material. Scanning transmission electron microscopy (STEM) is an option for this task. To obtain statistically relevant results, STEM‐images many have be acquired and evaluated. This time‐consuming if it done manually. In...
Methanol as a green and renewable resource can be used to generate hydrogen by reforming, <italic>i.e.</italic>, its catalytic oxidation with water.
Nanoporous gold (NPG) obtained by dealloying Ag75Au25 with an overall residual Ag content of less than 1% was investigated as electrocatalyst for the oxidation methanol, formaldehyde, and formate in aqueous 0.1 M NaOH solution. The NPG used to fill cavity microelectrodes, which allowed recording well-resolved voltammetry from porous material. differs polycrystalline Au (Au(poly)) its microstructure also behaves distinctly different Au(poly). is higher at surface ligaments bulk. By cycling...
Ceria–titania mixed oxides on a structured nanoporous gold support result in highly active and durable catalysts for the water-gas shift reaction.
Abstract Hetero‐contacts are interfaces between different materials at the nanoscale leading to novel functional properties. In hetero‐aggregates, primary particles of least two mixed particle or cluster level. Double flame spray pyrolysis (DFSP) is a versatile technique for controlled synthesis such materials. Characterization hetero‐aggregates by scanning transmission electron microscopy (STEM) requires acquisition and evaluation many aggregate images in order derive statistically...
Summary Atomic electric fields in a thin GaN sample are measured with the centre‐of‐mass approach 4D‐scanning transmission electron microscopy (4D‐STEM) using 12‐segmented STEM detector Spectra 300 microscope. The fields, charge density and potential compared to simulations an experimental measurement pixelated 4D‐STEM detector. segmented benefits from high recording speed, which enables measurements at low radiation doses. However, there is uncertainty due limited number of segments...
Abstract The 3D nano/microstructure of materials can significantly influence their macroscopic properties. In order to enable a better understanding such structure-property relationships, microscopy techniques be deployed, which are however often expensive in both time and costs. Often 2D imaging more accessible, yet they have the disadvantage that cannot directly retrieved from measurements. motivation this work is overcome issues characterizing structures measurements for hetero-aggregate...
Dealloying of Ag–Au nanoparticles strongly differs from bulk alloys and is controlled by electrochemical conditions Au surface atom mobility.
Abstract Dry reforming of methane (DRM) is an attractive reaction for synthesis gas production, since it converts two greenhouse gases into valuable chemical feedstock. Silica supported bimetallic catalysts with constant metal loading but varying Ni/Co ratios ( x Ni =1, 0.8, 0.6, 0.5, 0.4, 0.2, 0) were produced via spray‐drying the application in DRM, aiming at identification compositions superior activity. In this study, building block particles refer to inert framework, supporting...
Strain has a strong effect on the properties of materials and performance electronic devices. Their ever shrinking size translates into constant demand for accurate precise measurement methods with very high spatial resolution. In this regard, transmission electron microscopes are key instruments thanks to their ability map strain subnanometer Here, we present method measure at nanometer scale based diffraction Bessel beams. We demonstrate that our offers sensitivity better than 2.5 × 10−4...
Nanoporous gold as obtained by corrosion of alloys and a less noble metal is system with manifold applications. The process dealloying, however, can result in partially porous samples, when dealloying conditions are not optimized respect to composition pre-treatment the master alloy. In present work, we investigate interface between material non-porous alloy two which either stopped automatically or was interrupted manually. Reasons for unintended termination former case suggested.
Abstract In this article we shed light on newly emerging perspectives to characterize and understand the interplay of diffusive mass transport surface catalytic processes in pores gas phase metal catalysts. As a case study, nanoporous gold, as an interesting example exhibiting well-defined pore structure high activity for total partial oxidation reactions is considered. PFG NMR (pulsed field gradient nuclear magnetic resonance) measurements allowed here quantitative evaluation diffusivities...
We investigate the composition of α-phase intermediate layers at epitaxial Ga2O3/Al2O3 interfaces using high angle annular dark field scanning transmission electron microscopy. Their presence is considered a general phenomenon as they are observed independent growth technique [Schewski et al., Appl. Phys. Exp. 8, 011101]. Samples were grown by plasma assisted molecular beam epitaxy different conditions. Almost these, quantitative evaluation measured intensities gave Ga concentrations ∼25%....
Reversible macroscopic length changes in nanoporous structures can be achieved by applying electric potentials or exposing them to different gases liquids. Thus, these materials are interesting candidates for applications as sensors actuators. Macroscopic originate from microscopic of crystal lattice parameters. In this report, we show spatially resolved measurements strain dealloyed gold. The results confirm theory indicating a compression the along axis cylindrically shaped ligaments and...