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Ambient pressure XPS for operando studies of (photoelectro)chemical reactions at the solid-liquid interface

English title Ambient pressure XPS for operando studies of (photoelectro)chemical reactions at the solid-liquid interface
Applicant Osterwalder Jürg
Number 170747
Funding scheme R'EQUIP
Research institution Physik-Institut Universität Zürich
Institution of higher education University of Zurich - ZH
Main discipline Condensed Matter Physics
Start/End 01.01.2017 - 31.12.2018
Approved amount 370'028.00
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All Disciplines (2)

Discipline
Condensed Matter Physics
Physical Chemistry

Keywords (6)

solid/liquid interfaces; catalysis; surface science; electron spectroscopy; atmospheric chemistry; solar fuel

Lay Summary (German)

Lead
Chemische Analytik von (photoelektro)chemischen Reaktionen an wohldefinierten fest-flüssig-Grenzflächen mit Hilfe von Elektronenspektroskopie
Lay summary

Viele wichtige chemische, physikalische und biologische Prozesse laufen an der Phasengrenze zwischen einem festen Stoff und einer Flüssigkeit ab. Diese Art von Grenzflächen sind sehr schwierig zugänglich für die Charakterisierung ihrer chemisches Eigenschaften und Reaktionen, da die entsprechenden Signale von den Volumensignalen überdeckt werden. In den letzten Jahren wurde die Methode APXPS eingeführt (ambient pressure XPS), womit chemische Analytik mit Röntgen-Photoelektronenspektroskopie (XPS) bei Drücken von mehreren zehn Millibar möglich wird. Insbesondere sind solche Messungen möglich an wenigen Nanometer dünnen Wasserfilmen auf einer festen Oberfläche, welche im Gleichgewicht mit dem entsprechenden Wasserdampfdruck sind. In diesem Projekt wird ein Vakuumsystem aufgebaut, in dem solche Experimente mit Hilfe von Synchrotronstrahlung am Paul-Scherrer-Institut gemacht werden können. In der selben Anlage können wohldefinierte Oberflächen präpariert und mit Standardmethoden im Ultrahochvakuum charakterisiert werden, bevor sie in Kontakt mit dem Wasserfilm gebracht werden. Gleichzeitig kann die Grenzschicht zusammen mit dem Wasserfilm ein Teil einer elektrochemischen Zelle sein und/oder mit Licht beschienen werden, was das direkte Verfolgen von (photo)elektrochemischen Reaktionen erlaubt. Mit diesem Instrument sollen unter anderem die elektrochemische Delamination von Graphen und Bornitrid-Monolagen von Metaloberflächen studiert werden, die photokatalytische Wasserspaltung und weitere katalytische Reaktionen auf Oxidoberflächen, sowie Reaktionen zwischen Oxidoberflächen und Wasser welche in der Atmosphärenchemie von Bedeutung sind.

Direct link to Lay Summary Last update: 28.11.2016

Responsible applicant and co-applicants

Collaboration

Group / person Country
Types of collaboration
Prof. Anders Nilsson / Stockholm University Sweden (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
Dr. Marco Favaro / Helmholtz Zentrum Berlin Germany (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
Dr. Ethan Crumlin / Advanced Light Source, LBL United States of America (North America)
- in-depth/constructive exchanges on approaches, methods or results
- Publication

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
5th International Workshop on Ambient Pressure XPS Talk given at a conference New APXPS endstation at the Swiss Light Source for the Study of Model Catalysts (invited) 13.12.2018 Berlin, Germany Osterwalder Jürg;


Associated projects

Number Title Start Funding scheme
149492 The surface chemistry of tropospheric gas - particle interactions 01.12.2013 Project funding (Div. I-III)
169176 Multiphase kinetics and chemistry at aqueous solution and mineral oxide - air interfaces 01.01.2017 Project funding (Div. I-III)
158188 Selective Oxidation of ethanol on modified supported Au catalysts: from fundamentalunderstanding to improved performance 01.10.2015 Project funding (Div. I-III)
200303 Model systems for single-atom catalysts and 2D-confined catalysis studied by in situ surface science methods 01.04.2021 Project funding (Div. I-III)
172641 Surface physics with single-layer materials and molecular layers 01.04.2017 Project funding (Div. I-III)
153312 Surface physics with single-layer materials and molecular layers 01.04.2014 Project funding (Div. I-III)
157148 In situ Studien zur Bildung und Metamorphose amorpher Kalcium Karbonat Kluster 01.10.2015 Project funding (Div. I-III)

Abstract

Many important chemical, physical and biological processes occur at the interface between a solid and a liquid. This is inherently a buried interface and, as such, not easily accessible with surface sensitive methods for chemical analysis. This proposal requests funding for an instru-ment that will enable us to carry out in situ and operando XPS experiments at solid-liquid interfaces and at near ambient pressures in one chamber, and to apply standard surface science preparation and characterization methods for atomically well defined samples in a second chamber under UHV conditions, with a transfer chamber in between. This system will be connected to the existing near ambient pressure photoemission (NAPP) spectrometer at PSI, where it will be used as a mobile end station at two different beamlines of the Swiss Light Source. The solid-liquid ambient pressure XPS (SLAPXPS) chamber will be designed along similar lines as a highly successful chamber at the Advanced Light Source (ALS) at Lawrence Berkeley Laboratory (Beamline 9.3.1), where a liquid water container can be placed directly underneath the sample analysis position, from which the sample can pull a few nanometer thick water film into the area probed by XPS. This provides not only access to direct chemical analysis at the solid-liquid interface, but the sample can also be configured in a three-electrode setup for in situ electrochemistry with potential control above the sample surface. The proposed system will go beyond what is available at the ALS with respect to sample preparation facilities. In the connected UHV preparation chamber well defined single crystalline substrates of metals, metal oxides and semiconductors can be prepared and routinely characterized, ultrathin metal and oxide films can be grown, and molecular monolayers can be deposited. The combination is unique and powerful and will boost the research activities of the three applicants in several fields. The Osterwalder group will prepare monolayers of molecular catalysts and photosensitizers for photoelectrochemical water splitting reactions on oxide surfaces and study their surface chemistry under operando conditions. A second project addresses the electrochemical delamination of graphene and single-layer hexagonal boron nitride, which is the crucial step in the transfer of CVD grown 2D materials from their metal growth substrate to other substrates. The van Bokhoven group will characterize model catalysts based on oxide single crystal surfaces and quantify the oxygen vacancy formation in the presence of gaseous or liquid water as well as gas phase reductants and oxidants. Moreover, the growth mechanism of oxides inside a liquid layer containing ions relevant to their synthesis will be investigated. The Ammann group will be able to characterize adsorbed water and liquid water on well defined oxide surfaces by means of electron yield oxygen K-edge NEXAFS, in the context of the heterogeneous ice nucleation where substrate-water interactions are important drivers. The interface of ice layers with sea salt brines will also be studied.
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