A5079851803- Ferroelectric and Piezoelectric Materials
- Microwave Dielectric Ceramics Synthesis
- Catalytic Processes in Materials Science
- Catalysis and Oxidation Reactions
- Combustion and Detonation Processes
- Electronic and Structural Properties of Oxides
- Multiferroics and related materials
- Dielectric properties of ceramics
- Acoustic Wave Resonator Technologies
- Catalysts for Methane Reforming
- Advanced ceramic materials synthesis
- Risk and Safety Analysis
- Fire dynamics and safety research
- Catalysis and Hydrodesulfurization Studies
- Dielectric materials and actuators
- Process Optimization and Integration
- Cold Fusion and Nuclear Reactions
- History and advancements in chemistry
- Thermal Expansion and Ionic Conductivity
- Particle Dynamics in Fluid Flows
- Advanced Sensor and Energy Harvesting Materials
- Industrial Gas Emission Control
- Electrophoretic Deposition in Materials Science
- Nanomaterials and Printing Technologies
- Gas Sensing Nanomaterials and Sensors
Forschungszentrum Jülich
2009-2024
RWTH Aachen University
2005-2022
Jülich Aachen Research Alliance
2021
Institute of Chemistry
2007
École Polytechnique Fédérale de Lausanne
2005
Abstract BaTiO 3 powders with various crystallite sizes, which were prepared through microemulsion‐mediated synthesis, thoroughly studied by Raman spectroscopy. Clear evidence for the presence of tetragonal phase was found ultrafine an average size above 30 nm. The lifetime phonons that are specifically assigned to decreased decreasing below a critical 100 In particles as fine nm, short mean free path phonons, mainly due internal pressure, causes decoupling coupled A 1 (TO) and diffuse...
NaNbO3 powders with various particle sizes (ranging from 30 nm to several microns) and well-controlled stoichiometry were obtained through microemulsion-mediated synthesis. The effect of size on the phase transformation prepared was studied using X-ray powder diffraction, Raman spectroscopy, nuclear site group analysis based these spectroscopic data. Coarsened particles exhibit an orthorhombic Pbcm (D2h11, no. 57) structure corresponding bulk structure, as observed for single crystals or by...
Abstract BaTiO 3 dense ceramics with different grain sizes from 5.6 µm down to 35 nm were thoroughly studied by Raman spectroscopy. The temperature characteristics of optical phonons compared those obtained for powders. micrograined ceramic revealed the well‐known spectrum profiles and transitions, typical bulk . On other hand, spectra a nanograined an average size tetragonally distorted pure phase showing diffused transition behaviour respect temperature. Abnormality phonon damping was...
Abstract The washcoat composition and the catalytic properties of two commercially available lean NO x traps (LNTs) were investigated. Both catalysts contained nominally same storage materials but differed strongly in their amount activity as well layered architecture. In lean‐rich cycle experiments under realistic engine‐out gas compositions using a laboratory test bench, LNTs showed comparable behavior. At temperatures below 250 °C, phase durations last up to 300 s until 50 % capacity is...
In the present work a flexible approach for wet chemical processing of nanocomposite functional thin films is demonstrated. Barium titanate (BTO) based future miniaturized multi-layer ceramic capacitors are chosen as model systems to introduce concept "hybrid solutions" which consist stabile mixtures reverse micelle derived BTO nanoparticle dispersions and conventional molecular precursor solutions either same (BTO:BTO) or specifically different material such zirconia (BTO:ZrO2). While in...
The present study reports on the preparation and structural characterization of dense NaNbO3 ceramics with ultrafine grain size. Nanocrystalline raw powders obtained via microemulsion mediated synthesis were consolidated to green compacts, sinterforged ceramic pellets high density ultra-fine microstructure finally annealed under different thermal regimes in order systematically increase average size range from several hundreds nm up a few μm. Structural these materials included...
Abstract The present study gives an overview on the potential, possibilities and perspectives that synthesis of functional materials, such as BaTiO 3 , with microemulsions reaction medium offers. Well defined nanocrystalline particles in form powders for further ceramic processing, well stable colloidal dispersions preparation coatings may be obtained. paper describes formation, phase behaviour stabilization related water/oil/surfactant systems used a nanoreactor during particle formation....
Inkjet printing was applied to manufacture silica‐based gas separation membranes, which were coated on a pore‐graduated alumina substrate with mesoporous γ‐alumina interlayer. A silica sol diluted by 1‐propanol used print the membrane layer followed thermal treatment in rapid processing furnace. The thickness varied between 30 and 110 nm conducting one, two, three coating steps. In latter case, H 2 permeance range of 2.0 × 10 −8 –3.3 mol/s·m ·Pa combined /CO selectivities 15–25 achieved,...
Spark plasma sintering (SPS) was used to densify BaTiO 3 –Ni composite powders relative densities above 92.8%. With the increasing Ni content, a decrease in density is observed, suggesting that hampers consolidation process. The microstructures of composites were duplex character. crystallite size ‐grains around 100 nm average. ceramic matrix phase surrounded inclusions approximately 1 μm diameter completely incorporated without formation any elongated metallic filaments. ac conductivity...
Passive autocatalytic recombiners (PARs) have been installed inside light water reactor containments in many countries to remove hydrogen and, thus, mitigate the combustion risk during a severe accident (SA). Due challenging SA boundary conditions, PARs are exposed several deactivation risks operation, which may cause reduction of removal capacity. Such occur through different mechanisms and could principle affect start-up behavior up full loss catalytic activity. To assess interaction with...
In addition to SCR systems, lean NOX traps (LNTs) are also used for exhaust aftertreatment of burn internal combustion engines sustainably reduce emissions. Modern LNTs consist different functional compounds maximize the performance during storage and regeneration. Based on material analysis a serial production LNT, PGM loaded BaO, Al2O3, MgAl2O4, CeO2 were identified as main base materials. this paper, capacity (NSC) these is investigated both single catalysts physical mixtures identify...
Abstract Multiple active component catalysts for efficient conversion of CO 2 to Methanol (MeOH) are synthesized through coating γ‐Al O 3 carrier spheres by incipient wetness impregnation method (IWI). The well‐known bimetallic Copper Oxide/Zinc Oxide (CuO/ZnO)is promoted in three steps, first Cerium (CeO ), then additionally with Zirconium (ZrO ) and finally Calcium (CaO) resulting four high surface area catalyst pore volume. Quaternary quinary moderate CeO , ZrO the quaternary (20 % CZCZ)...