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Ambient pressure x-ray photoelectron spectroscopy

Involved people:
Benjamin Reinecke, postdoc
Niclas Johansson, PhD student
Payam Shayesteh, PhD student
Joachim Schnadt

Collaborators:
Jan Knudsen (MAX IV Laboratory)
Samuli Urpelainen (MAX IV Laboratory)
Margit Andersson (MAX IV Laboratory)
Andrey Shavorskiy (MAX IV Laboratory)
Suyun Zhu (MAX IV Laboratory)
Antonio Bartalesi (MAX IV Laboratory)
Ashley Head (Lawrence Berkeley Laboratory)
Jean-Jacques Gallet, Fabrice Bournel, and François Rochet (Université Pierre et Marie Curie, Paris)
Jeppe Vang Lauritsen, Flemming Besenbacher, Aarhus University, Stig Helveg, Poul Georg Moses, Michael Brorson, Haldor Topsøe A/S

Description
During the past years we have built up a new activity focused at the use of x-ray photoelectron spectroscopy for in situ surface science studies. In particular, we have built up the Swedish ambient pressure x-ray photoelectron spectroscopy instrument on the SPECIES beamline on the MAX II ring of the MAX IV Laboratory, and we are in charge of the HIPPIE beamline project to be realised at the new MAX IV facility.

While traditional x-ray photoelectron spectroscopy is limited to vacuum environments of 10-6 mbar and better, the technical development of ambient pressure x-ray photoelectron spectroscopy, driven forward in particular by groups in Berlin and Berkeley (Bluhm, Schlögl, Salmeron et al.), allows the measurement of x-ray photoelectron spectroscopy at maximum pressures of around 1 to 10 mbar. Such a pressure is sufficiently high to allow the study of the influence of a gas phase chemical potential on the state and dynamic development of a surface, and completely new perspectives are opened up for the use of surface scientific methods.

The instrument, which we have installed in Lund and which was developed in collaboration with SPECS GmbH, is special in terms of that it enables the dual use of ultrahigh vacuum x-ray and ambient pressure x-ray photoelectron spectroscopy on the very same sample. This is made possible by the use of a dedicated high pressure cell in an ultrahigh vacuum environment. This cell also allows the fast switching of gas composition, a feature which is highly favourable for the study of chemical reactions at surfaces.

The primary focus of our in situ studies is the investigation of catalytic samples and processes as well as growth processes. We study both surface-supported metal element nanoparticles, oxide films, and transition metal complexes. A very important goal is to widen our perspective and to study complex surfaces and reactions, including epoxidation, preferential oxidation, C-H activation, and Atomic layer deposition (ALD).

The real-time monitoring of ALD project is in collaboration with the LPC-MR group at Université Pierre et Marie Curie in Paris, with whom we also collaborate on the development of instrumentation for Ambient pressure x-ray photoelectron spectroscopy within the MAX IV-SOLEIL collaboration.

Another collaboration effort together with Aarhus University and Haldor Topsøe A/S in Denmark - the "CAT-C" project - is funded by the Danish Strategic Research Council. CAT-C stands for Clean Air Technologies by Development of New Catalysts, and the project is concered - on a fundamental level - with the hydrodesulphurisation of crude oil and the NOx reduction.

 

Transition metal complexes at surfaces

Involved people:
Olesia Snezhkova, PhD student
Ekaterina Bolbat, PhD student (Centre for Analysis and Synthesis)
Niclas Johansson, PhD student
Joachim Schnadt

Collaborators:
Ola Wendt, Centre for Analysis and Synthesis, Lund University
Petter Persson and Fredric Ericsson, Theoretical Chemistry, Lund University
Roberto Otero, Universidad Autónoma de Madrid
Barbara Brena and Johann Lüder, Uppsala University
Willie Auwärter and Alissa Wiengarten, Technische Universität München
Marie-Laure Bocquet, ENS Lyon

The chemistry of transition metal complexes has been one of the central topics of chemistry for more than a century now. The high chemical versatility and variability of transition metal complexes has implied that the topic has remained at the heart of anorganic chemistry until today, and transition metal complexes retain their most important role in catalysis research and other areas.

Transition metal complexes have entered surface chemistry and physics much later, around twenty years ago. It is only during the past years that it has been investigated how the properties of surface-adsorbed transition metal complexes can be both altered and used.

Our focus is on the properties of two types of surface-adsorbed transition metal complexes, phthalocyanines and metal salen complexes. We have been able to show that the spin states of iron phthalocyanine can be tuned to different values by the adsorption of different ligands. More recently, we investigate how the choice of support can affect the chemical and spin state of phthalocyanines and salen comeplexes, and we investigate the catalytic properties of surface-adsorbed phthlaocyanines, salen, as well as Pd complexes.

This work forms part of our activities within the previous Marie Curie Initial Training Network SMALL.

 

Immobilisation of molecular catalysts and polymer nanoparticles at surfaces

Involved people:
Shilpi Chaudhary, PhD student
Tripta Kamra, PhD student
Payam Shayesteh, PhD student
Ekaterina Bolbat, PhD student (Centre for Analysis and Synthesis)
Maitham Majeed, PhD student (Centre for Analysis and Synthesis)
Joachim Schnadt

Collaborators:
Ola Wendt, Centre for Analysis and Synthesis, Lund University
Lei Ye, Pure and Applied Biochemistry, Lund University
Lars Montelius, Solid State Physics, Lund University
Petter Persson, Theoretical Chemistry, Lund University

As a result of synthetic chemists' outstanding ability of designing molecular materials with a highly specific active site, such materials are typically extremely efficient and/or selective for the task that they have been made for. Such tasks comprise e.g. catalytic and biosensing applications. The materials are then typically used in a homogeneous liquid phase, which also contains the reactants at which the materials aim. It would be favourable, however, if they could be heterogenised, i.e. anchored to a surface, which then is immersed in the reactant gas or liquid phase. The huge advantage lies in the much simplified separation of catalytic/sensing material and reactants and products. Yet, the anchoring of molecular materials is by far not trivial, since the interaction with the surface can significantly change the molecular materials' chemical, physical, and electronic properties.

Our activity aims at the precise characterisation of heterogenised molecular materials for catalytic and sensing purposes by surface science methods. In particular, this also comprises the investigation under in situ conditions.

This work forms part of our activities within the previous Marie Curie Initial Training Network SMALL.

 

Catalytic nanoparticles

Involved people:
Sheetal Sisodiya, PhD student (Centre for Analysis and Synthesis)
Shilpi Chaudhary, PhD student
Niclas Johansson, PhD student
Payam Shayesteh, PhD student
Joachim Schnadt

Collaborators:
Ola Wendt, Centre for Analysis and Synthesis, Lund University
Ashley Head (Lawrence Berkeley Laboratory)
Bjørk Hammer and Michael Groves, Aarhus University

Especially since the ground-breaking discovery around 25 years ago that the otherwise inert element gold is highly catalytically active for a variety of chemical reactions when in nanoparticle form, immense effort has been invested in the practical catalytic application of nanoparticular gold and other elements as well as the elucidation of the catalytic principles behind the activity.

Our efforts target the function and use of catalytic gold particles for reactions which are complex from a surface science point-of-view. Hence, we have investigated coupling reactions both over flat Au surfaces and over surface-immobilised Au particles. We have also targeted the in situ formation of nanoreactors containing disperse gold nanoparticles with the goal of carrying out oxidation reactions of alkenes.


Lunds universitet, Avdelningen för synkrotronljusfysik
Besöks- och leveransadress: Sölvegatan 14, 223 62 Lund
Postadress: Box 118, 221 00 Lund
Fakturaadress: Box 188, 221 00 Lund
OBS! Beställarens för- och efternamn måste alltid anges som referens på fakturan!

Lund University, Division of Synchrotron Radiation Research
Visiting and delivery address: Sölvegatan 14, 223 62 Lund, Sweden
Mail address: Box 118, 221 00 Lund, Sweden
Billing address: Box 188, 221 00 Lund, Sweden
Please observe that all bills have to contain the orderer's first and last name as the reference.

Phone: +46 (0)46-222 00 00, Fax: +46 (0)46-222 42 21
Publisher: Joachim Schnadt