Florian Schweinberger

Florian Schweinberger
Roche · Diagnostics - R&D

Dr. rer. nat.

About

38
Publications
3,511
Reads
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1,259
Citations
Citations since 2017
8 Research Items
846 Citations
2017201820192020202120222023050100150
2017201820192020202120222023050100150
2017201820192020202120222023050100150
2017201820192020202120222023050100150
Additional affiliations
September 2017 - July 2018
Roche
Position
  • Researcher
June 2008 - August 2008
Koc University
Position
  • IAESTE Summer Intern

Publications

Publications (38)
Article
Palladium based systems are used extensively in a wide range of catalytic hydrogenation reactions. Here, electronic modifications of two amorphous SiO2 thin films are used to influence the properties of supported Pd nanoparticles (≈1 nm). Negative charging of the metal particles leads to destabilization of both, surface and subsurface hydrogen spec...
Article
Size-selected metal clusters supported on metal oxides have recently gained significant scientific attention due to their potential to investigate hydrogenation reactions on a fundamental level. To expand previous studies on ethylene hydrogenation, we report on the selective hydrogenation of 3-hexyne using the same model systems of Pt clusters supp...
Article
Full-text available
In the present work, the degradation of size-selected Pt nanoclusters is studied under electrochemical conditions. This model catalyst mimics carbon supported Pt nanoclusters and nanoparticles typically employed in proton exchange membrane fuel cells (PEMFCs). Insight into the early stage of degradation is given by high-angle annular dark-field sca...
Article
The preparation of organic ligands-free, isolated tantalum oxide atoms (Ta1) and small clusters (Tan>1) on flat silicate supports was accomplished by ultra-high vacuum (UHV) techniques followed by oxidation in air. The resulting surface complexes were thoroughly characterized and tested as supported catalysts for the epoxidation of cycloalkenes. Th...
Article
Nanometer-sized metal clusters are prime candidates for photoactivated catalysis, based on their unique tunable optical and electronic properties, combined with a large surface-to-volume ratio. Due to the very small optical cross sections of such nanoclusters, support-mediated plasmonic activation could potentially make activation more efficient. O...
Article
The use of physico-chemical preparation techniques of metal clusters in the ultra-high vacuum (UHV) allows for high control on cluster nuclearity and size distribution for fundamental studies in catalysis. Surprisingly, the potential of these systems as catalysts for organic chemistry transformations in solution has not been explored. To this end s...
Article
Gelten Reaktivitätskorrelationen auch für Materie im Subnanometerbereich? Die Antwort geben Platincluster, auf die das Wissen aus größeren Dimensionen angewendet wird. Solche Eigenschaften vorhersagen zu können trägt dazu bei, Metallkatalysatoren zu verstehen und neue zu entwickeln.
Article
The H2/D2 exchange reaction was studied on mono-disperse Pt8 clusters in a μ-reactor. The chemical activity was studied at temperatures varying from room temperature to 180 °C using mass spectrometry. It was found that minute amounts of O2 in the gas stream increased the chemical activity significantly. XPS and ISS before and after reaction suggest...
Article
Ethylene hydrogenation was investigated on size-selected Pt13 clusters supported on three amorphous silica (a-SiO2) thin films with different stoichiometries. Activity measurements of the reaction at 300 K revealed that on a silicon-rich and a stoichiometric film, Pt13 exhibits a similar activity to that of Pt(111), in line with the known structure...
Article
Ethylene hydrogenation was investigated on size-selected Pt13 clusters supported on three amorphous silica (a-SiO2 ) thin films with different stoichiometries. Activity measurements of the reaction at 300 K revealed that on a silicon-rich and a stoichiometric film, Pt13 exhibits a similar activity to that of Pt(111), in line with the known structur...
Article
The nature of the nano-catalyzed hydrogenation of ethylene, yielding benchmark information pertaining to the concept of structure sensitivity/insensitivity and its applicability at the bottom of the catalyst particle size-range, is explored with experiments on size-selected Ptn (n = 7–40) clusters soft-landed on MgO, in conjunction with first-princ...
Article
Ethylene hydrogenation catalyzed at 300 K by 1--1.5 nm nanoparticles of Ni, Pd and Pt supported on MgO(1 0 0) with a narrow size-distribution, as well as the deactivation under reaction conditions at 400 K, was investigated with pulsed molecular beam experiments. Ni nanoparticles deactivate readily at 300 K, whereas Pd particles deactivate only aft...
Article
Full-text available
The sensitivity, or insensitivity, of catalysed reactions to catalyst structure is a commonly employed fundamental concept. Here we report on the nature of nano-catalysed ethylene hydrogenation, investigated through experiments on size-selected Ptn (n=8-15) clusters soft-landed on magnesia and first-principles simulations, yielding benchmark inform...
Data
Supplementary Figures 1-36, Supplementary Note 1-2 and Supplementary References
Article
Metal oxide thin films grown on metal single crystals are commonly used to model heterogeneous catalyst supports. The structure and properties of thin silicon dioxide films grown on metal single crystals have only recently been thoroughly characterized and their spectral properties well established. We report the successful growth of a three- dimen...
Chapter
This chapter is dedicated to the utilized methods and their underlying theoretical background.
Chapter
The chapter is divided into four major parts, illustrating the capabilities of the MIES/UPS setup towards application for adsorption studies and cluster science as well as investigation of the reactivity of olefins on Pt clusters.
Chapter
The results of investigations of supported size-selected Pt cluster catalysts under ambient and more applied conditions is described in this chapter.
Chapter
In the presented work different aspects of supported Pt cluster catalysts were studied under well defined UHV and applied ambient conditions. In the following the achieved results and gained insights are summarized.
Chapter
The phenomenon of catalysis, the acceleration (of the rate) of a chemical reaction by means of a (catalyst) material through an energetically favorable mechanism, is a concept known for almost 200 years. The technological revolution in the last century would not have been possible without catalysis and nowadays approximately 85–90 % of the products...
Article
Employing rationally designed model systems with precise atom-by-atom particle size control, we demonstrate by means of combining non-invasive in situ Indirect Nanoplasmonic Sensing and ex situ Scanning Transmission Electron Microscopy that monomodal size-selected platinum cluster catalysts on different supports exhibit remarkable intrinsic sinteri...
Chapter
This part is split into three sub sections. First a brief introduction, covering the studied reactions and their mechanisms is presented. Second, the fundamentals of the electronic structure of model systems and adsorbed species, with a focus on electron emission spectroscopy (EES) are discussed. Last, the motivation for studying catalyst model sys...
Book
Supported, size-selected Platinum clusters (8–68 atoms), as sophisti-cated heterogeneous model catalyst system, were investigated with respect to different aspects of their catalytic properties as a function of size. Under ultra high vacuum conditions the electronic structure, adsorption properties and reactivity of two olefins on surfaces and Pt c...
Article
The photocatalytic water reduction reaction on CdS nanorods was studied as function of Pt cluster size. Maximum H2 production is found for Pt46. This effect is attributed to the size dependent electronic properties (e.g. LUMO) of the clusters with respect to the band edges of the semiconductor. This observation may be applicable for the study and i...
Article
The diminished surface-area-normalized catalytic activity of highly dispersed Pt nanoparticles compared with bulk Pt is particularly intricate, and not yet understood. Here we report on the oxygen reduction reaction (ORR) activity of well-defined, size-selected Pt nanoclusters; a unique approach that allows precise control of both the cluster size...
Article
In the present study size-selected platinum clusters fabricated by a laser ablation source are investigated with respect to the oxygen reduction reaction. Pt46 Clusters were deposited onto planar carbon surfaces leading to different cluster coverages between 0.018 clusters / nm² and 0.115 clusters / nm². In all cases the coverage on the glassy carb...
Article
By means of ultraviolet photoelectron spectroscopy (UPS) and metastable impact electron spectroscopy (MIES), combined with temperature programmed desorption (TPD) experiments, the coverage dependent adsorption properties of trichloroethene (TCE) on Mo(100), Mo(112) and Pt(111) support were probed and are compared to findings on MgO(100). Peaks in t...
Article
We introduce size-selected subnanometer cluster catalysts deposited on thin films of colloidal semiconductor nanocrystals as a novel platform to obtain atomic scale insight into photocatalytic generation of solar fuels. Using Pt-cluster-decorated CdS nanorod films for photocatalytic hydrogen generation as an example, we determine the minimum amount...
Article
Full-text available
Poly(2-ethyl-2-oxazoline) (PEOX) formed self-assembled fibers in aqueous solutions above the cloud point temperature (Tc) through a slow crystallization process. The fiber formation above Tc happened both in pure water and in the presence of salting-in (SCN−) and salting-out (CH3COO−) ions. The crystal structure and the melting temperature of the P...
Article
The separation of ultraviolet photoelectron spectroscopy (UPS) and metastable impact electron spectroscopy (MIES) is usually performed by a time-of-flight (ToF) separation using pre-set ToF for both types of signal. In this work, we present a new, improved ex situ signal separation method for the separation of MIES and UPS for every single measurem...
Article
Full-text available
Nanotechnologies promise to contribute significantly to major technological challenges of the upcoming century. Despite profound scientific progress in the last decades, only minor advances have been made in the field of nanomaterial toxicology. The International Team in Nanosafety (TITNT) is an international and multidisciplinary group of scientis...
Article
In the presented study the influence of electrochemical treatments on size-selected Pt nanoclusters (NCs) supported on amorphous carbon is investigated by means of transmission electron microscopy (TEM). Well-defined Pt NCs are prepared by an ultra-high vacuum (UHV) laser vaporization source and deposited with low kinetic energy (≤10eV/cluster) ont...
Article
Employing ultraviolet photoelectron spectroscopy (UPS, He I), the more surface sensitive metastable impact electron spectroscopy (MIES) and temperature programmed desorption (TPD) measurements of the adsorption properties of the pollutant trichloroethylene (TCE) on thin MgO(100) films, grown on a Mo(100) single crystal, have been investigated. From...
Article
First results of investigations are presented, where size-selected metal clusters generated in ultra high vacuum (UHV) are transferred to ambient conditions and tested for suitable electrochemical applications. As demonstrated, the transfer allows for the characterization of clusters by transmission electron microscopy (TEM) as well as catalytic me...
Article
Using p-MBRS experiments and TPR as well as FTIR measurements, it could be shown that dissociative oxygen activation occurs in the same temperature range for small clusters in comparison to faceted nanoparticles (NPs) and Pd single crystals. Surprisingly, CO poisoning does not take place on small Pd clusters at temperatures above 300 K. Furthermore...

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