A5062331066- Advancements in Solid Oxide Fuel Cells
- Electronic and Structural Properties of Oxides
- Electrocatalysts for Energy Conversion
- Fuel Cells and Related Materials
- Magnetic and transport properties of perovskites and related materials
- Catalytic Processes in Materials Science
- Catalysis and Oxidation Reactions
- X-ray Diffraction in Crystallography
- Gas Sensing Nanomaterials and Sensors
- Crystallization and Solubility Studies
- Chemical Looping and Thermochemical Processes
- CO2 Reduction Techniques and Catalysts
- Ammonia Synthesis and Nitrogen Reduction
- Ferroelectric and Piezoelectric Materials
- Semiconductor materials and devices
- Analytical Chemistry and Sensors
- Electrochemical Analysis and Applications
- Transition Metal Oxide Nanomaterials
- Layered Double Hydroxides Synthesis and Applications
- Carbon dioxide utilization in catalysis
- Ionic liquids properties and applications
- Advancements in Battery Materials
- Membrane-based Ion Separation Techniques
- Laser-induced spectroscopy and plasma
- Advanced Photocatalysis Techniques
TU Wien
2016-2025
Massachusetts Institute of Technology
2021
Christian Doppler Laboratory for Thermoelectricity
2016-2020
Interface (United States)
2015-2019
Forschungszentrum Jülich
2016-2019
Abstract Over the last decade, exsolution has emerged as a powerful new method for decorating oxide supports with uniformly dispersed nanoparticles energy and catalytic applications. Due to their exceptional anchorage, resilience various degradation mechanisms, well numerous ways in which they can be produced, transformed applied, exsolved have set standards terms of activity, durability functionality. In conjunction multifunctional such perovskite oxides, becomes platform design advanced...
The oxygen exchange activity of mixed conducting oxide surfaces has been widely investigated, but a detailed understanding the corresponding reaction mechanisms and rate-limiting steps is largely still missing. Combined in situ investigation electrochemically polarized model electrode under realistic temperature pressure conditions by near-ambient (NAP) XPS impedance spectroscopy enables very surface-sensitive chemical analysis may detect species that are involved step. In present study,...
Any substantial move of energy sources from fossil fuels to renewable resources requires large scale storage excess energy, for example, via power fuel processes. In this respect electrochemical reduction CO2 may become very important, since it offers a method sustainable CO production, which is crucial prerequisite synthesis fuels. Carbon dioxide in solid oxide electrolysis cells (SOECs) particularly promising owing the high operating temperature, leads both improved thermodynamics and fast...
The temperature dependent conductivity of yttria stabilized zirconia (YSZ) exhibits a bending in Arrhenius' plots which is frequently discussed terms free and associated oxygen vacancies. However, the very high doping concentration YSZ leads to such strong defect interaction that concept vacancies becomes highly questionable. Therefore, reconsidered. with different was measured broad range. data are analyzed two barrier heights have be passed along an average path vacancy (two model). For...
Abstract La 0.6 Sr 0.4 CoO 3– δ (LSC) thin‐film electrodes are prepared on yttria‐stabilized zirconia (YSZ) substrates by pulsed laser deposition at different temperatures. The decrease of the film crystallinity, occurring when temperature is lowered, accompanied a strong increase electrochemical oxygen exchange rate LSC. For more or less X‐ray diffraction (XRD)‐amorphous deposited between ca. 340 and 510 °C polarization resistances as low 0.1 Ω cm 2 can be obtained 600 °C. Such films also...
Abstract In the search for optimized cathode materials high‐temperature electrolysis, mixed conducting oxides are highly promising candidates. This study deals with fundamentally novel insights into relation between surface chemistry and electrocatalytic activity of lanthanum ferrite based electrolysis cathodes. For this means, near‐ambient‐pressure X‐ray photoelectron spectroscopy (NAP‐XPS) impedance experiments were performed simultaneously on electrochemically polarized La 0.6 Sr 0.4 FeO...
Cation diffusion was investigated in La0.6Sr0.4CoO3-δ (LSC) thin films on (100) yttria stabilized zirconia the temperature range 625-800 °C. Isotopic ((86)Sr) and elemental tracers (Fe, Sm) were used to establish profiles of cations bi- multi-layered films. The analyzed by time flight-secondary ion mass spectrometry (ToF-SIMS). Grain grain boundary coefficients determined for LSC with columnar grains - along boundaries is shown be about three orders magnitude faster than grains. This could...
Solid oxide fuel cells (SOFCs) exhibit potential to become a key technology for future clean energy systems. The metal-supported SOFC exhibits decisive strengths like fast start-up capability, mechanical robustness, and acceptable cost, making it the concept of choice mobile applications. As promising example, SOFC-powered range extenders electric vehicles offer refueling significantly increased driving range, while lowering size, weight, cost vehicle's battery. Here, we report development...
Exsolution generates stable and catalytically active metal nanoparticles via phase precipitation out of a host oxide. An ability to control the size dispersion exsolution particles is desirable for design nanostructured (electro)catalysts. Here, we demonstrate that tuning point defects by lattice strain affects both thermodynamics kinetics iron (Fe0) on La0.6Sr0.4FeO3 (LSF) thin film model. By combining in situ surface characterization ab initio defect modeling, show oxygen vacancy Schottky...
Reverse Water-Gas Shift (rWGS) is among the reactions with highest readiness level for technological implementation of CO2 utilization as an abundant and renewable carbon source, its transformation instance into synthetic fuels. Hence, great efforts are made in terms further development comprehension novel catalyst materials. To achieve excellent catalytic performance, catalytically active (nano)particles that evenly distributed on (and ideally embedded in) support crucial. An extremely...
A novel operation mode for time of flight-secondary ion mass spectrometry (ToF-SIMS) is described a TOF.SIMS 5 instrument with Bi-ion gun. It features sub 100 nm lateral resolution, adjustable primary currents and the possibility to measure high resolution as well resolution. The adjustment performance are compared established ToF-SIMS modes. Several examples application featuring scientific results show capabilities in terms accuracy isotope analysis oxygen, combination relationship between...
Owing to its extraordinary high activity for catalysing the oxygen exchange reaction, strontium doped LaCoO3 (LSC) is one of most promising materials solid oxide fuel cell (SOFC) cathodes. However, under SOFC operating conditions this material suffers from performance degradation. This loss electrochemical has been extensively studied in past and an accumulation at LSC surface shown be responsible degradation effects. The present study sheds further light onto changes also occurring...
Abstract Exsolution of metal nanoparticles from perovskite-type oxides is a very promising approach to obtain catalysts with superior properties. One particularly interesting property exsolution the possibility electrochemical switching between different activity states. In this work, synchrotron-based in-situ X-ray diffraction experiments on electrochemically polarized La 0.6 Sr 0.4 FeO 3-δ thin film electrodes are performed, in order simultaneously insights into phase composition and...
In this study, five different mixed conducting cathode materials were grown as dense thin films by pulsed laser deposition (PLD) and characterized
Detailed insight into electrochemical reaction mechanisms and rate limiting steps is crucial for targeted optimization of solid oxide fuel cell (SOFC) electrodes, especially new materials processing techniques, such as Ni/Gd-doped ceria (GDC) cermet anodes in metal-supported cells. Here, we present a comprehensive model that describes the impedance porous electrodes according to transmission line circuit. We exemplify validity on electrolyte-supported symmetrical cells with two equal...
In heterogeneous catalysis, surfaces decorated with uniformly dispersed, catalytically-active (nano)particles are a key requirement for excellent performance. Beside standard catalyst preparation routines—with limitations in controlling surface structure (i.e., particle size distribution or dispersion)—we present here novel time efficient route to precisely tailor morphology and composition of perovskites. Perovskite-type oxides nominal ABO3 transition metal cations on the B-site can exsolve...
Solid oxide fuel electrodes with pure GDC as the functional layer exhibit excellent kinetics, in line mechanistic impedance modelling.
Abstract Nanostructured functional oxides play an important role in enabling clean energy technologies and novel memory processor devices. Using thin‐film La 0.6 Sr 0.4 FeO 3 (LSF) as a model system, the utility of exsolution fabricating self‐assembled metal oxide nanocomposites with tunable functionalities is shown. Exsolution triggers formation metallic iron (Fe 0 ) nanoparticles, Ruddlesden–Popper domains, nm‐scale percolated Fe‐deficient channels LSF. Combining multimodal...
Minimizing the overpotential at air electrode of solid oxide fuel cells (SOFC) is one key challenges regarding a broad applicability this technology. Next to novel materials and geometry optimization, surface modification promising flexible method alter oxygen exchange kinetics SOFC cathode surfaces. Despite extensive research, mechanism behind effect decorations still under debate. Moreover, for Sr decoration, previous studies yielded conflicting results, reporting either beneficial or...
Owing to its mixed ionic and electronic conductivity high thermochemical stability, La0.6Sr0.4FeO3-δ (LSF64) is an attractive electrode material in solid oxide fuel/electrolysis cells (SOFCs/SOECs). Well defined thin film microelectrodes are used compare the electrochemical properties of LSF64 oxidizing reducing conditions. The sheet resistance hydrogen can be overcome by use additional metallic current collector. With being compensated, area specific similar humidified oxygen containing...
Nanoparticle exsolution is regarded as a promising alternative to classical catalyst synthesis routes. In this work, we compare the catalytic performance of nanoparticles formed by in-situ during dry reforming methane with particles pre-formed reductive pre-treatment. The experiments were conducted on three perovskite-type oxides. Using combination and operando spectroscopic investigations (x-ray diffraction, near ambient pressure x-ray photoelectron spectroscopy) correlation obtained...
The oxygen exchange kinetics of platinum on yttria-stabilized zirconia (YSZ) was investigated by means geometrically well-defined Pt microelectrodes. By variation electrode size and temperature it possible to separate two regimes with different geometry dependencies the polarization resistance. At higher temperatures (550–700 °C) an elementary step located close three phase boundary (TPB) activation energy ∼1.6 eV identified as rate limiting. lower (300–400 limiting is related area exhibited...