A5073106048- Catalytic Processes in Materials Science
- Electrocatalysts for Energy Conversion
- Catalysis and Oxidation Reactions
- Graphene research and applications
- Electron and X-Ray Spectroscopy Techniques
- Advanced Photocatalysis Techniques
- Semiconductor materials and devices
- Electronic and Structural Properties of Oxides
- ZnO doping and properties
- Quantum Dots Synthesis And Properties
- Catalysts for Methane Reforming
- Nanomaterials for catalytic reactions
- Transition Metal Oxide Nanomaterials
- Electrochemical Analysis and Applications
- Calcium Carbonate Crystallization and Inhibition
- Copper-based nanomaterials and applications
- Catalysis and Hydrodesulfurization Studies
- Gas Sensing Nanomaterials and Sensors
- Paleontology and Stratigraphy of Fossils
- Fuel Cells and Related Materials
- Advanced Electron Microscopy Techniques and Applications
- Surface and Thin Film Phenomena
- Mesoporous Materials and Catalysis
- Molecular Junctions and Nanostructures
- nanoparticles nucleation surface interactions
Technical University of Munich
2022-2025
ETH Zurich
2018-2024
Fritz Haber Institute of the Max Planck Society
2013-2024
Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement
2022-2024
Center for Environmental Economics - Montpellier
2018-2024
ShanghaiTech University
2022
Max Planck Institute of Colloids and Interfaces
2016-2020
Board of the Swiss Federal Institutes of Technology
2019-2020
Max Planck Society
2016-2018
Scope
2018
A one-pot, hydrothermal synthesis of nitrogen and sulfur dual doped carbon aerogels is presented, derived from our previously published carbonization approach. Two co-monomers, S-(2-thienyl)-L-cysteine (TC) 2-thienyl carboxaldehyde (TCA), were used for incorporation, giving rise to distinct morphologies varying doping levels sulfur. Nitrogen-doping 5 wt% sulfur-doping 1 (using TCA) 4 TC) obtained. secondary pyrolysis step was further tune the aerogel conductivity heteroatom binding states....
Hollowing Out Metal Oxide Nanoparticles Corrosion is normally a problem, but it can be useful, for example, when you wish to create hollow metal nanoparticles, whereby the reduction of one species in solution drives dissolution core particle. Oh et al. (p. 964 ; see Perspective by Ibáñez and Cabot ) adapted this approach oxide nanoparticles placing Mn 3 O 4 nanocrystals with Fe 2+ ions, which replaces nanocrystal exterior γ-Fe 2 . At sufficiently high concentrations, nanocages formed. These...
In industrially relevant Cu/ZnO/Al2 O3 catalysts for methanol synthesis, the strong metal support interaction between Cu and ZnO is known to play a key role. Here we report detailed chemical transmission electron microscopy study on nanostructural consequences of in an activated high-performance catalyst. For first time, clear evidence formation metastable "graphite-like" layers during reductive activation provided. The description this layer might contribute understanding synergistic...
Active and highly stable oxide-supported IrNiO(x) core-shell catalysts for electrochemical water splitting are presented. IrNi(x)@IrO(x) nanoparticles supported on high-surface-area mesoporous antimony-doped tin oxide (IrNiO(x)/Meso-ATO) were synthesized from bimetallic IrNi(x) precursor alloys (PA-IrNi(x) /Meso-ATO) using Ni leaching concomitant Ir oxidation. Special emphasis was placed Ni/NiO surface segregation under thermal treatment of the PA-IrNi(x)/Meso-ATO as well chemical state...
The notorious instability of non-precious-metal catalysts for oxygen reduction and evolution is by far the single unresolved impediment their practical applications. We have designed highly stable active bifunctional reversible electrodes oxidative thermal scission, where we concurrently rupture nitrogen-doped carbon nanotubes oxidize Co Mn nanoparticles buried inside them to form spinel Mn-Co oxide partially embedded in nanotubes. Impressively high dual activity achieved using these...
Cost‐efficient, visible‐light‐driven hydrogen production from water is an attractive potential source of clean, sustainable fuel. Here, it shown that thermal solid state reactions traditional carbon nitride precursors (cyanamide, melamine) with NaCl, KCl, or CsCl are a cheap and straightforward way to prepare poly(heptazine imide) alkali metal salts, whose thermodynamic stability decreases upon the increase atom size. The chemical structure prepared salts confirmed by results X‐ray...
We report an operando examination of a model nanocrystalline In2O3 catalyst for methanol synthesis via CO2 hydrogenation (300 °C, 20 bar) by combining X-ray absorption spectroscopy (XAS), powder diffraction (XRD), and in situ transmission electron microscopy (TEM). Three distinct catalytic regimes are identified during hydrogenation: activation, stable performance, deactivation. The structural evolution nanoparticles (NPs) with time on stream (TOS) followed XANES-EXAFS-XRD associates the...
Thanks to their remarkably high activity toward oxygen reduction reaction (ORR), platinum-based octahedrally shaped nanoparticles have attracted ever increasing attention in last years. Although activities for ORR catalysts been attained, the practical use is still limited by long-term stability. In this work, we present Rh-doped Pt–Ni octahedral with up 1.14 A mgPt–1 combined improved performance and shape stability compared previous bimetallic particles. The synthesis, electrocatalytic of...
Complementary in situ X-ray photoelectron spectroscopy (XPS), diffractometry, and environmental scanning electron microscopy are used to fingerprint the entire graphene chemical vapor deposition process on technologically important polycrystalline Cu catalysts address current lack of understanding underlying fundamental growth mechanisms catalyst interactions. Graphene forms directly metallic during high-temperature hydrocarbon exposure, whereby an upshift binding energies corresponding C1s...
The dynamic interactions between noble metal particles and reducible metal-oxide supports can depend on redox reactions with ambient gases. Transmission electron microscopy revealed that the strong metal-support interaction (SMSI)-induced encapsulation of platinum titania observed under reducing conditions is lost once system exposed to a redox-reactive environment containing oxygen hydrogen at total pressure ~1 bar. Destabilization interface redox-mediated reconstructions lead particle...
Abstract Heterogeneous catalysts play a pivotal role in the chemical industry. The strong metal-support interaction (SMSI), which affects catalytic activity, is phenomenon researched for decades. However, detailed mechanistic understanding on real systems lacking. Here, this surface was studied an actual platinum-titania catalyst by state-of-the-art situ electron microscopy, X-ray photoemission spectroscopy and diffraction, aided density functional theory calculations, providing novel time...
Hydrogen production by electrocatalytic water splitting will play a key role in the realization of sustainable energy supply. Owing to their relatively high stability and activity, iridium (hydr)oxides have been identified as most promising catalysts for oxidation water. Comprehensive spectroscopic theoretical studies on basis rutile IrO2 provided insight about electronic structure active X-ray amorphous phase. However, due absence long-range order missing information local arrangement...
This work highlights the importance of in situ experiments for an improved understanding graphene growth on copper via metal-catalyzed chemical vapor deposition (CVD). Graphene inside chamber a modified environmental scanning electron microscope under relevant low-pressure CVD conditions allows visualizing structural dynamics active catalyst simultaneously with nucleation and unparalleled way. It enables observation complete process from substrate annealing through and, finally, cooling real...
Abstract Potassium poly(heptazine imide) (PHI) is a photocatalytically active carbon nitride material that was recently prepared from substituted 1,2,4‐triazoles. Here, we show the more acidic precursors, such as commercially available 5‐aminotetrazole, upon pyrolysis in LiCl/KCl salt melt yield PHI with greatly improved structural order and thermodynamic stability. Tetrazole‐derived PHIs feature long‐range crystallinities unconventionally small layer stacking distances, leading to altered...
Fossil-free ironmaking is indispensable for reducing massive anthropogenic CO2 emissions in the steel industry. Hydrogen-based direct reduction (HyDR) among most attractive solutions green ironmaking, with high technology readiness. The underlying mechanisms governing this process are characterized by a complex interaction of several chemical (phase transformations), physical (transport), and mechanical (stresses) phenomena. Their interplay leads to rich microstructures, hierarchy defects...
Facile autoreduction of iron oxide encapsulated within carbon nanotubes has been observed at a temperature 200 degrees C lower than those on the outer surface. This opens new route to tune state confined nanoparticles d-band metals by confinement CNTs.
Abstract A symbiosis of advanced scanning probe and electron microscopy a well‐defined model system may provide detailed picture interfaces on nanostructured catalytic systems. This was demonstrated for Pt nanoparticles supported iron oxide thin films which undergo encapsulation by supporting as result strong metal–support interactions.
Platinum nanoparticles dispersed on nanosized ceria are active for CO oxidation at room temperature after hydrogen pretreatment. High angular annular dark field scanning transmission electron microscopy (HAADF-STEM) analysis of the reduced catalyst shows spreading 1 nm sized platinum particles under beam, characteristic a two-dimensional strong metal–support interaction. In situ X-ray absorption fluorescence spectroscopy (XAFS) reveals Pt–O distance 2.1 Å, which is significantly longer than...
Abstract In industrially relevant Cu/ZnO/Al 2 O 3 catalysts for methanol synthesis, the strong metal support interaction between Cu and ZnO is known to play a key role. Here we report detailed chemical transmission electron microscopy study on nanostructural consequences of in an activated high‐performance catalyst. For first time, clear evidence formation metastable “graphite‐like” layers during reductive activation provided. The description this layer might contribute understanding...
Dry reforming of methane (DRM) has been studied for many years as an attractive option to produce synthesis gas. However, catalyst deactivation by coking over nonprecious-metal catalysts still remains unresolved. Here, we study the influence structural and compositional properties nickel on catalytic performance propensity in DRM. A series bulk with different Ni contents was synthesized calcination hydrotalcite-like precursors NixMg0.67–xAl0.33(OH)2(CO3)0.17·mH2O prepared constant-pH...
Intercalation of oxygen at the interface graphene grown by chemical vapour deposition and its polycrystalline copper catalyst can have a strong impact on electronic, structural properties both Cu. This affect oxidation resistance metal as well subsequent transfer. Here, we show, using near ambient pressure X-ray photoelectron spectroscopy (NAP-XPS), absorption edge (XANES), energy dispersive (EDX) (environmental) scanning electron microscopy (ESEM) that intercalation de-intercalation are...