A5074048659- Electrocatalysts for Energy Conversion
- Nuclear physics research studies
- Catalytic Processes in Materials Science
- Electronic and Structural Properties of Oxides
- Nuclear Physics and Applications
- Advanced Chemical Physics Studies
- Laser-Ablation Synthesis of Nanoparticles
- Copper-based nanomaterials and applications
- Electrochemical Analysis and Applications
- Pharmacovigilance and Adverse Drug Reactions
- Advanced battery technologies research
- Graphene research and applications
- Multiferroics and related materials
- Sociology and Education Studies
- Advancements in Battery Materials
- Atomic and Molecular Physics
- Diamond and Carbon-based Materials Research
- Quantum Chromodynamics and Particle Interactions
- Social and Demographic Issues in Germany
- Semiconductor materials and interfaces
- Supercapacitor Materials and Fabrication
- Nuclear reactor physics and engineering
- Adipose Tissue and Metabolism
- Academic integrity and plagiarism
- Electron and X-Ray Spectroscopy Techniques
University of Duisburg-Essen
2016-2025
International Society of Nephrology
2023
Institut für Technische und Angewandte Physik (Germany)
2020
BG Klinikum Duisburg
2015
Federal Institute for Drugs and Medical Devices
2003-2009
Deggendorf Institute of Technology
1970-1985
Helmholtz-Zentrum Dresden-Rossendorf
1981
Joint Institute for Nuclear Research
1971-1972
Polyclinic Medical University
1967
University of Freiburg
1966
The three-dimensional (3D) distribution of individual atoms on the surface catalyst nanoparticles plays a vital role in their activity and stability. Optimising performance electrocatalysts requires atomic-scale information, but it is difficult to obtain. Here, we use atom probe tomography elucidate 3D structure 10 nm sized Co2FeO4 CoFe2O4 during oxygen evolution reaction (OER). We reveal nanoscale spinodal decomposition pristine Co2FeO4. interfaces Co-rich Fe-rich nanodomains become...
Co-based electrocatalysts are an emerging class of materials for the oxygen evolution reaction (OER). These undergo dynamic surface changes, converting to active Co oxyhydroxide (CoOOH) layer during OER. A better understanding structural, morphological, and elemental CoOOH formed OER is, therefore, crucial optimization electrocatalysts. Herein, we propose innovative multimodal method, which combines X-ray photoelectron spectroscopy, electron backscatter diffraction, high-resolution...
Specific ion effects ranking in the Hofmeister sequence are ubiquitous biochemical, industrial, and atmospheric processes. In this experimental study specific inexplicable by classical DLVO theory have been investigated at curved water-metal interfaces of gold nanoparticles synthesized a laser ablation process liquid absence any organic stabilizers. Notably, ion-specific differences colloidal stability occurred Hückel regime extraordinarily low salinities below 50 μM, indications direct...
The role of β-CoOOH crystallographic orientations in catalytic activity for the oxygen evolution reaction (OER) remains elusive. We combine correlative electron backscatter diffraction/scanning electrochemical cell microscopy with X-ray photoelectron spectroscopy, transmission microscopy, and atom probe tomography to establish structure-activity relationships various faceted formed on a Co microelectrode under OER conditions. reveal that ≈6 nm β-CoOOH(01 1‾${\bar{1}}$ 0), grown [...
Herein, coffee grounds derived biochar was used as support for the fabrication of NiFe2O4/biochar composite particles. The composites achieved up to 10x higher turnover frequencies (TOF) in photo-Fenton degradation tetracycline (20 mg/L) batch compared pure NiFe2O4 This could be correlated a decreased agglomeration, lower band gap energy and electronic interaction with biochar. hydrophobic further enabled incorporation powders into porous polyethersulfone (PES) membranes via film casting cum...
High-entropy alloys (HEAs) represent a promising material systems in the search for next-generation high-performance oxygen evolution reaction (OER) electrocatalysts. Developing HEA electrocatalysts requires thorough understanding of surface and subsurface reconstruction during OER their effects on activity stability. However, it is difficult most characterization techniques to resolve atomic-scale elemental distribution multiple elements composition. Herein, we combine atom probe tomography...
Like other 2D materials, the boron-based borophene exhibits interesting structural and electronic properties. While is typically prepared by molecular beam epitaxy, we report here on an alternative way of synthesizing large single-phase domains segregation-enhanced epitaxy. X-ray photoelectron spectroscopy shows that borazine dosing at 1100 °C onto Ir(111) yields a boron-rich surface without traces nitrogen. At high temperatures, thermally decomposes, nitrogen desorbs, boron diffuses into...
Two-dimensional semiconductors such as MoS2 are promising for future electrical devices. The interface to metals is a crucial and critical aspect these devices because undesirably high resistances due Fermi level pinning present, resulting in unwanted energy losses. To date, experimental information on junctions has been obtained mainly indirectly by evaluating transistor characteristics. fact that the metal–semiconductor typically embedded, further complicates investigation of underlying...
Abstract An atomic‐scale understanding of how electrocatalyst surfaces reconstruct and transform during electrocatalytic reactions is essential for optimizing their activity longevity. This particularly important the oxygen evolution reaction (OER), where dynamic substantial structural compositional changes occur reaction. Herein, a multimodal method developed by combining X‐ray fine structure absorption photoemission spectroscopy, transmission electron microscopy, atom probe tomography with...
Fe<sub>2</sub>O<sub>3</sub>/rGO nanocomposites were prepared by an electrostatic-interaction-induced self-assembling between the Fe<sub>2</sub>O<sub>3</sub> NPs and graphene oxide (GO) sheets, followed with a low-temperature hydrothermal reduction process.
Abstract Highly active, structurally disordered CoFe 2 O 4 /CoO electrocatalysts are synthesized by pulsed laser fragmentation in liquid (PLFL) of a commercial powder dispersed water. A partial transformation the educt to CoO is observed and proposed be thermal decomposition process induced picosecond irradiation. The overpotential OER aqueous alkaline media at 10 mA cm −2 reduced 23% compared down 0.32 V with Tafel slope 71 mV dec −1 . Importantly, catalytic activity systematically...
Laser ablation in liquids (LAL) drives the decomposition of liquid inducing formation a large number different redox equivalents and gases. This not only leads to shielding effects decrease nanoparticle (NP) productivity but also can directly affect NP properties such as oxidation degree. In this study, we demonstrate that during laser water is triggered by activity 7 bulk materials used; Au, Pt, Ag, Cu, Fe, Ti Al, well reactivity with plasma. less-noble metals like aluminum massive gas...
A systematic study on the microwave-assisted thermolysis of single source precursor (Et2Sb)2Te (1) in different asymmetric 1-alkyl-3-methylimidazolium- and symmetric 1,3-dialkylimidazolium-based ionic liquids (ILs) reveals distinctive role both anion cation tuning morphology microstructure resulting Sb2Te3 nanoparticles as evidenced by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive analysis (EDX), photoelectron spectroscopy (XPS). comparison electrical thermal...
Co3O4 nanoparticles were size- and shape-selectively synthesized in a solvothermal approach by the thermal decomposition of either cobalt(II) acetylacetonate [Co(acac)2] or nitrate [Co(NO3)2] different solvents followed calcination under air. Spherical, cubic, octahedral, platelike with narrow size distributions sizes ranging from 8 to 90 nm formed high yield. The characterized X-ray diffraction, scanning transmission electron microscopy, energy-dispersive analysis, photoelectron...
Abstract The effect of surface orientations on the formation iridium oxide species during oxygen evolution reaction (OER) remains yet unknown. Herein, we use a needle‐shaped atom probe specimen as nanosized working electrode to ascertain role in OER. At beginning electrolysis, top 2–3 nm (024), (026), (113), and (115) planes are covered by IrO−OH, which activates all surfaces towards A thick subsurface layer consisting sub‐stoichiometric Ir−O is formed open (024) OER proceeds. Such...
Abstract The ferroelectricity of multivalent codoped Bismuth ferrite (BiFeO 3 ; BFO) nanoparticles (NPs) is revealed and utilized for photocatalysis, exploiting their narrow electronic bandgap. photocatalytic activity ferroelectric photocatalysts BiFe 0.95 Mn 0.05 O (BFM) NPs mono‐, di‐, or tri‐valent cations (Ag + , Ca 2+ Dy 3+ MDT) coincorporated BFM are studied under ultrasonication in acidic conditions. It found that such doping enhances the approximately three times. correlation with...
Abstract Polyelemental material systems, specifically high‐entropy alloys, promise unprecedented properties. Due to almost unlimited combinatorial possibilities, their exploration and exploitation is hard. This challenge addressed by co‐sputtering combined with shadow masking produce a multitude of microscale libraries in one deposition process. These thin‐film composition spreads on the cover compositional ranges alloy systems enable high‐throughput characterization thousands compositions...
Abstract Core‐shell Co 3 O 4 @CoO nanoparticles were prepared by calcination of rock‐salt CoO and fully characterized PXRD, TEM XPS measurements. studies showed that the Co(III) cation concentration steadily increased OER activity resulting core‐shell decreased with increasing time, which was attributed to presence catalytically inactive cations. The decrease in also observed for untreated ( 1 ) after chronopotentiometric (CP) treatment at 10 mA cm −2 18 h. IR EEL spectra are comparable...
Abstract Optimizing electrocatalyst performance requires an atomic‐scale understanding of surface state changes and how those affect activity stability during the reaction. This is particularly important for oxygen evolution reaction (OER) since electrocatalytically active surfaces undergo substantial reconstruction transformation. Herein, a multimodal method employed that combines X‐ray photoemission spectroscopy, transmission electron microscopy, atom probe tomography, operando...
Spray-flame synthesis was used to produce high-surface-area perovskite electrocatalysts with high phase purity, minimum surface contamination, and electrochemical stability. In this study, as-prepared LaCo1–xFexO3 nanoparticles (x=0.2, 0.3, 0.4) were found contain a degree of combustion residuals, mostly consist both, stoichiometric oxygen-deficient phases. Heating them at moderate temperature (250 °C) in oxygen could remove residuals increases the content while preventing particle growth. A...
Bismuth ferrite (BFO) is the drosophila of research in multiferroic materials due to its simultaneous magnetic and electric ordering at room temperature. The unfortunate detail antiferromagnetic ordering, which practically cancels magnetization magnetoelectric coupling crystals. To induce finite coupling, dopants have been introduced with a certain success so far. Nanoparticles (NPs) can additionally constrain formation cycloid BFO size confinement. Doping nanoparticles thus potentially...
LaMnO3+δ nanoperovskites were prepared via the continuous and scalable spray-flame synthesis (SFS) technique from metal nitrate-based solutions by using either ethanol (EtOH) as solvent or a mixture of (50 vol %) 2-ethylhexanoic acid (EtOH/2-EHA). Solutions based on pure EtOH generated several phases broad multimodal particle size distribution, which is attributed to combination gas-to-particle droplet-to formation particles. The product contained bimodal distribution orthorhombic (Pnma II)...