In-Situ Photoelectron Spectroscopy at the Liquid-Nanoparticle and Liquid-Air Interface

June 30, 2015
4:00-5:00pm
414 CEPSR
Speaker: Dr. Giorgia Olivieri, Postdoctoral Researcher, Laboratory of Surface Science and Technology, Department of Materials, ETH Zürich, Switzerland

Abstract

With the developments of near ambient pressure photoemission (NAPP) and the liquid microjet, X-ray photoelectron spectroscopy (XPS) measurements at the liquid-nanoparticle interface are now possible. This significant advance allows soft matter physicists working in the field of colloid nanoscience the opportunity to perform surface science experiments long deemed impossible. Current themes that are strongly represented within our group are the spatial distribution of atmospherically relevant atomic and molecular ions in aqueous solutions, electronic and geometric structure of the water-oxide nanoparticles (NPs) interface, measurements of the true NPs surface potential under a variety conditions.

In this talk I begin by describing our new NAPP endstation at the Swiss Light Source and how it allows for the extension of in situ X-ray Photoelectron Spectroscopy (XPS) to the liquid-nanoparticle interface of colloidal suspensions. Two applications will be then illustrated in details. The first is a study of the electronic and geometric structures of a core-shell type nanoparticle, AlxOy@SiO2, suspended in aqueous solution and the adsorption of a simple molecule, formic acid, on the NP surface. In the second one I will show how a combined study of theory and experiments can be used to describe the depth profile distribution of ions in solution at the water/air interface.

Speaker Bio

After completing my Master degree in Physics from the University of Bologna I moved to the University of Trieste to start a PhD under the supervision of Alberto Morgante. During my PhD I spent most of my time at the ELETTRA synchrotron where I was performing spectroscopic surface science experiments on hybrid interfaces. I have also done six months internship in the CLUE laboratory in Columbia University working in the group of Ioannis Kymissis on tandem solar cells. My first postdoc was done in Paris where I worked in the group of François Rochet to install the new Near-Ambient Pressure X-ray Photoemission Spectroscopy (NAP-XPS) end station in the SOLEIL synchrotron. During this period I participated in all the NAP experiments from my group and I have also strongly collaborated with external users that arrived after one-year period of commissioning. My interest was in developing and studying model catalytic systems in order to bridge the gap between UHV studies and more realistic working conditions. Another topic of interest was the investigation of ions behavior at the liquid/air interfaces of electrolytic solutions.

I am currently doing my second postdoc at the ETH Zurich under the supervision of Matthew Brown where I am performing XPS experiments from a liquid microjet. This allows me to continue my studies on liquid/air and solid/liquid interfaces. During the last month I have also starting to work on theoretical simulations to better support and quantify the experimental findings.

Hosted by John Kymissis.


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