A5063355388- Electrocatalysts for Energy Conversion
- Advanced Chemical Physics Studies
- Catalytic Processes in Materials Science
- Spectroscopy and Quantum Chemical Studies
- nanoparticles nucleation surface interactions
- Electrochemical Analysis and Applications
- Catalysis and Oxidation Reactions
- Surface and Thin Film Phenomena
- Electrostatics and Colloid Interactions
- Nanowire Synthesis and Applications
- Molecular Junctions and Nanostructures
- ZnO doping and properties
- Advanced Battery Materials and Technologies
- Magnetic and transport properties of perovskites and related materials
- Fuel Cells and Related Materials
- Force Microscopy Techniques and Applications
- Quantum and electron transport phenomena
- Machine Learning in Materials Science
- Ga2O3 and related materials
- Chalcogenide Semiconductor Thin Films
- Semiconductor materials and interfaces
- Semiconductor materials and devices
- Electronic and Structural Properties of Oxides
- CO2 Reduction Techniques and Catalysts
- Advanced Materials Characterization Techniques
Universität Ulm
2016-2025
Helmholtz-Institute Ulm
2015-2021
Max Planck Institute for Chemical Physics of Solids
2019
University of Duisburg-Essen
2008-2015
University of Florida
2015
Technical University of Munich
2003-2005
The description of electrode-electrolyte interfaces is based on the concept formation an electric double layer. This was derived from continuum theories extended by introducing point charge distributions. Based ab initio molecular dynamics simulations, we analyze layer in approach beyond scheme instead assessing polarizations at electrochemical metal-water first principles. We show that atomic structure water layers room temperature leads to oscillatory behavior averaged electrostatic...
The structure of a liquid water layer on Pt(111) has been studied by ab initio molecular dynamics simulations based periodic density functional theory calculations. First the reliability chosen exchange-correlation function validated considering clusters, bulk ice structures, and water, confirming that dispersion corrected RPBE-D3/zero is suitable choice. at room temperature yield six layers thick sufficient to properties in interior film. Performing statistical average along trajectory,...
The electro-oxidation of methanol on Pt(111) is studied based periodic density functional theory calculations. aqueous electrolyte taken into account using an implicit solvent model, and the dependence reaction energetics electrode potential derived concept computational hydrogen electrode. total oxidation becomes thermodynamically preferred at potentials above U = 0.6 V relative to standard We propose a most favorable path involving surface carboxyl as last intermediate before CO2...
We present a computational study of the interface Pt electrode and an aqueous electrolyte employing semi-empirical dispersion corrections implicit solvent model within first-principles calculations. The potential is parametrized hydrogen scheme. Using one explicit layer, we find that most realistic configuration water bilayer in H-up configuration. Furthermore, focus on contribution interaction presence H, O, OH adsorption energies. This demonstrates scheme represents computationally...
The structure of water on metal electrodes is addressed based first-principles calculations. Special emphasis placed the competition between water-metal and water-water interaction as determining factors. Thus question will be discussed whether at surfaces ice- or rather liquid-like. proper description liquid phases requires to perform thermal averages. This has been done by combining electronic calculations with molecular dynamics simulations. After reviewing recent studies about flat,...
A structural analysis of solvating water layers on a Pt(111) electrode has been performed based extensive ab initio molecular dynamics simulations. We have emulated different electrochemical conditions by varying the concentration hydrogen ions in layers, which effectively corresponds to variation potential. present detailed arrangement and orientation molecules also address their mobility solvation layer.
It is shown that substitution of C or N for O recently proposed as a way to create ferromagnetism in otherwise nonmagnetic oxide insulators curtailed by formation impurity pairs, and the resultant C2 spin=1 dimers well isoelectronic N2(2+) interact antiferromagnetically p-type MgO. For C-doped ZnO, however, we demonstrate using Heyd-Scuseria-Ernzerhof hybrid functional resonance spin-polarized ppπ* states with host conduction band results long-range ferromagnetic interaction. Magnetism...
We determine the detailed differences in geometry and band structure between wurtzite (Wz) zinc blende (Zb) InAs nanowire (NW) surfaces using scanning tunneling microscopy/spectroscopy photoemission electron microscopy. By establishing unreconstructed defect-free surface facets for both Wz Zb, we can reliably measure valence conduction edges, local vacuum levels, geometric relaxations to few-millielectronvolt few-picometer respectively. Surface bulk density functional theory calculations...
Over the past years, density functional theory (DFT) became a widely approved and successful method for calculating properties of various materials molecules. Especially suited systems with delocalized electrons like metals, efficient treatment van der Waals interaction remained problem DFT functionals within generalized gradient approximation (GGA). Combining Grimme's D3 correction RPBE using previously published data set, we show that this yields is well-suited an accurate balanced...
The theoretical modeling of metal/water interfaces centers on an appropriate configuration the electric double layer (EDL) under grand canonical conditions. In principle, ab initio molecular dynamics (AIMD) simulations would be choice for treating competing water-water and water-metal interactions explicitly considering atomic electronic degrees freedom. However, this approach only allows relatively small ensembles over a limited period (shorter than 100 ps). On other hand, computationally...
The CO adsorption on ordered Cu–Pd alloy surfaces and surface alloys has been studied using density functional theory (DFT) within the framework of generalized gradient approximation (GGA). On alloys, energy at top sites decreases with increasing concentration more reactive metal Pd. This surprising ligand effect is caused by effective compressive strain induced larger size Pd atoms. other hand, most favorable binding becomes stronger which an ensemble related to availability higher...
The partial and total oxidation of methanol on clean oxygen-precovered Cu(110) has been studied by periodic density functional theory calculations within the generalized gradient approximation. Reaction paths including geometry energetics several reaction intermediates activation barriers between them have determined, thus creating a complete scheme for copper. demonstrate that specific structure oxygen copper plays an important role in both methanol. For lower concentrations surface, to...
A path through a crowd Catalytic reactions on surfaces occur at pressures which the are completely covered with adsorbed molecules. It would seem that this arrangement interfere reactants encountering one another diffusion processes. Henß et al. used high-speed scanning tunneling microscopy to follow of oxygen atoms ruthenium surface was fully carbon monoxide (CO) molecules (see Perspective by Magnussen). Oxygen-atom unexpectedly fast. theoretical model revealed CO appears open pathways for...
The formation energies of GaAs nanowires have been calculated from a structural motif approach supported by first-principles data for small-diameter nanowires. bulk material has zincblende (ZB) structure, but the ground state may be either ZB or wurtzite (WZ), possibly depending on energetic contributions their surfaces and edges. are cut in $\left[111\right]$ direction $\left[0001\right]$ WZ respectively. We consider with hexagonal cross sections ${11\overline{2}0}$ ${10\overline{1}0}$...
Density functional theory (DFT) calculations are used to determine the vibrational modes of hydrogen adsorbed on graphene in low-coverage limit. Both calculated adsorption energy a H atom 0.8 eV and C-H stretch frequency 2552 cm(-1) unusually low for hydrocarbons, but agreement with data from electron loss spectroscopy hydrogenated graphite. The clustering two atoms observed scanning tunneling microscopy images shows its fingerprint also our spectra. energetically preferred different...
CO adlayers on Pt(111) electrode surfaces are an important electrochemical system and of great relevance to electrocatalysis. The potential-dependent structure dynamics these complex still controversial, especially in the pre-oxidation regime. We here employ situ high-speed scanning tunneling microscopy for studying surface phase behavior CO-saturated 0.1 m H