A5054022692- Electrocatalysts for Energy Conversion
- Electrochemical Analysis and Applications
- Catalytic Processes in Materials Science
- Molecular Junctions and Nanostructures
- Photochromic and Fluorescence Chemistry
- Catalysis and Oxidation Reactions
- Porphyrin and Phthalocyanine Chemistry
- Copper-based nanomaterials and applications
- Hydrogen Storage and Materials
- Advancements in Battery Materials
- Advanced battery technologies research
- Fuel Cells and Related Materials
- Electronic and Structural Properties of Oxides
- Photochemistry and Electron Transfer Studies
- CO2 Reduction Techniques and Catalysts
- Electron and X-Ray Spectroscopy Techniques
- Surface and Thin Film Phenomena
- Semiconductor materials and devices
- Hybrid Renewable Energy Systems
- X-ray Spectroscopy and Fluorescence Analysis
- Organic Electronics and Photovoltaics
- Iron oxide chemistry and applications
- Catalysts for Methane Reforming
Friedrich-Alexander-Universität Erlangen-Nürnberg
2018-2023
Comprehensive Cancer Center Erlangen
2019
University of Würzburg
1999
Co oxides and oxyhydroxides have been studied extensively in the past as promising electrocatalysts for oxygen evolution reaction (OER) neutral to alkaline media. Earlier studies showed formation of an ultrathin CoO x (OH) y skin layer on Co3O4 at potentials above 1.15 V vs reversible hydrogen electrode (RHE), but precise influence this OER reactivity is still under debate. We present here a systematic study epitaxial spinel-type films with defined (111) orientation, prepared different...
Quantitative assessment of the charge transfer phenomena in cobalt oxides and complexes is essential for design advanced catalytic materials. We propose a method evaluation oxidation state with mixed valence states using resonant photoemission spectroscopy. The based on calculation enhancement ratio (RER) from heights features associated Co3+ Co2+ states. nature corresponding was corroborated by means density functional calculations. employed well-ordered Co3O4(111) film to calibrate RER...
Abstract Cobalt oxide is a promising earth abundant electrocatalyst and one of the most intensively studied oxides in electrocatalysis. In this study, structural dynamics well‐defined cobalt nanoislands (NIs) on Au(111) are investigated situ under potential control. The samples prepared ultra‐high vacuum system characterized using scanning tunneling microscopy (STM). After transfer into electrochemical environment, structure, mobility, dissolution via (EC) STM, cyclic voltammetry, EC on‐line...
We have explored the stability, structure, and chemical transformations of atomically defined Co3O4(111) thin films under electrochemical conditions. The well-ordered were prepared on an Ir(100) single crystal ultrahigh vacuum (UHV) conditions subsequently transferred characterized in environment by means cyclic voltammetry (CV), scanning flow cell inductively coupled plasma mass spectrometry (SCF-ICP-MS), infrared reflection absorption spectroscopy (EC-IRRAS). found that are stable...
Oxide supports can modify and stabilize platinum nanoparticles (NPs) in electrocatalytic materials. We studied related phenomena on model systems consisting of Pt NPs atomically defined Co3O4(111) thin films. Chemical states dissolution behavior catalysts were investigated as a function the particle size electrochemical potential by ex situ emersion synchrotron radiation photoelectron spectroscopy online inductively coupled plasma mass spectrometry. Electronic metal–support interaction...
Molecular solar thermal (MOST) systems combine energy conversion, storage, and release in simple one-photon one-molecule processes. Here, we address the electrochemically triggered from an azothiophene-based MOST system by photoelectrochemical infrared reflection absorption spectroscopy (PEC-IRRAS) density functional theory (DFT). Specifically, back-reaction rich (Z)-3-cyanophenylazothiophene to its lean (E)-isomer using highly oriented pyrolytic graphite (HOPG) as working electrode was...
Model studies at complex, yet well-defined electrodes can provide a better understanding of electrocatalytic reactions. New experimental devices are required to prepare such model electrocatalysts with atomic-level control. In this work, we discuss the design new setup, which enables preparation in ultra-high vacuum (UHV) using full portfolio surface science techniques. The setup allows for direct transfer samples from UHV and immersion into electrolyte without contact air. As special...
Employing molecular photoswitches, we can combine solar energy conversion, storage, and release in an extremely simple single molecule system. In order to the stored as electricity, photoswitch has interact with a semiconducting electrode surface. this work, explore solar-energy-storing model system, consisting of anchored atomically defined oxide surface liquid electrolyte under potential control. Previously, system been proven be operational ultrahigh vacuum (UHV) conditions. We used...
Electronic metal–support interactions play a key role in the design of heterogeneous catalysts, as they provide tool for tuning catalytic properties and enhancing catalyst stability. In this work, we explore electrocatalysis using model approach. We investigate adsorption reaction behavior atomically defined Pt/Co3O4 catalysts under ultrahigh vacuum (UHV) electrochemical conditions. The systems were prepared by physical vapor deposition (PVD) Pt onto well-ordered Co3O4(111) films on Ir(100),...
We have studied particle size effects on atomically-defined model catalysts both in ultrahigh vacuum (UHV) and under electrochemical (EC) conditions liquid electrolytes. The were prepared UHV by physical vapour deposition (PVD) of Pt onto an ordered Co3O4(111) film Ir(100), yielding nanoparticles (NPs) with average from 10 to 500 atoms per (0.8 3 nm). systems characterized using surface science methods including scanning tunnelling microscopy (STM), before transferring them out the into...
Abstract 2-Propanol and its dehydrogenated counterpart acetone can be used as a rechargeable electrofuel. The concept involves selective oxidation of 2-propanol to in fuel cell coupled with reverse catalytic hydrogenation closed cycle. We studied electrocatalytic on complex model Pt/Co 3 O 4 (111) electrocatalysts prepared ultra-high vacuum characterized by scanning tunneling microscopy. behavior the has been investigated alkaline media (pH 10, phosphate buffer) means electrochemical...
Molecular solar thermal (MOST) systems open application fields for energy conversion as they combine conversion, storage, and release in one single molecule. For release, catalysts must be controllable, selective, stable over many operation cycles. Here, we present a MOST/catalyst couple, which combines all these properties. We explore storage tailor-made MOST system (cyano-3-(3,4-dimethoxyphenyl)-norbornadiene/quadricyclane; NBD′/QC′) the heterogeneously catalyzed at Au(111) surface. By...
PtCu bimetallic alloys are known to provide better activity than pure platinum in proton exchange membrane fuel cells. However, such catalysts undergo complex degradation processes during cell operation, resulting deterioration of their activity. By using situ electrochemical (EC) atomic force microscopy combined with EC infrared reflection absorption spectroscopy, we a comprehensive investigation morphological and structural transformations model thin film accelerated tests (ADTs). The ADTs...
In this work, we investigated the interaction of phenylphosphonic acid (PPA, C6H5PO3H2) with atomically-defined Co3O4(111) thin films, grown on Ir(100), under ultrahigh vacuum (UHV) conditions and in electrochemical environment. first step, employed infrared reflection absorption spectroscopy (IRAS) followed formation a saturated monolayer (380 K) UHV. We observed that binding motif changes from chelating tridentate sub-monolayer regime to bidentate at full coverages. environment, analyzed...
The metastability of the Pd<sub>6</sub>C phase results from thermodynamically favorable growth graphene.
The need for environmental friendly and sustainable energy conversion has triggered renewed interest into the electrochemical photoelectrochemical splitting of water. A key challenge in this field is development economically viable electrocatalyst materials oxygen evolution reaction (OER). Transition-metal oxide catalysts, particular cobalt (hydr)oxide materials, have been found as promising candidates, since they are earth-abundant, efficient scalable over a wide range conditions [1]. They...