Project

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Ultrafast Equilibrium and Nonequilibrium Dynamics at Solid-Liquid Interfaces

Applicant Dereka Bogdan
Number 201996
Funding scheme Ambizione
Research institution Institut für Chemie Universität Zürich
Institution of higher education University of Zurich - ZH
Main discipline Physical Chemistry
Start/End 01.02.2022 - 31.01.2026
Approved amount 911'933.00
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Keywords (10)

Ultrafast spectroscopy; Electric double layer; Solvation; Interfaces; Surface science; Electrostatic catalysis; Time-resolved infrared; Transient spectroscopy; 2D IR; Ions

Lay Summary (German)

Lead
We are trying to understand how being in the first nanometer from the boundary between solid and liquid affects molecular chemical reactions and physical processes compared to when the molecules are very far away from this boundary.
Lay summary
Most important chemical, physical, technological and biological processes are happening near the interface between two phases: whether it is on a surface of the ocean, atop of the membrane in a living cell or on an electrode in a Li-ion battery inside a smartphone. These examples highlight just a tiny fraction of the vast number of processes that benefit from the unique environment that the interfacial region brings about. It is truly remarkable how different the first nanometer from the surface is from the bulk of any material, whether it is water, metal or a piece of rock. However, this boundary region is extremely difficult to interrogate experimentally and to directly watch the process in question occurring in real time. Especially, when "real time" means natural time scale for molecules, that is a period when chemical bonds vibrate, break, form and rearrange. This scale (called femtosecond) is as short when compared to a second as a second itself is short when compared to the age of the Universe.

This project is aimed at advancing the state-of-the-art laser spectroscopic tools to directly watch chemical reactions at so-called buried interfaces: the boundary between solid and liquid without interference from the bulk of these phases. It is our ultimate goal to not only directly watch the reactions happening specifically in this nanometer thin layer at the interface, but also to manipulate them by applying specifically tailored electric fields and surface-attached molecular arrangements. We have developed a broad selection of approaches to attack this problem from multiple sides. It is our hope that the fundamental findings that we expect to obtain from the experiments will be useful for applied science to enhance the current catalysis and battery techonologies.
Direct link to Lay Summary Last update: 13.01.2022

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Abstract

Fundamental physical and chemical processes at surfaces are of paramount importance in chemistry, physics, biology and technology. Direct interrogation of their dynamics at solid-liquid interface at room temperature on the timescale of molecular motion is difficult because only few methods have the combination of necessary sensitivity and temporal resolution. As a result, a rather static picture of the dynamic fluctuating world of the interfaces has been painted. The proposed research plan focuses on investigating the fundamental aspects of the structural dynamics and chemical reactivity on the fs-ns timescale at catalytic and electrified interfaces. The specific aims are: i) to develop tools able to interrogate interfacial equilibrium structures and their fluctuations by means of ultrafast two-dimensional infrared (2D IR) spectroscopy and photoinduced chemical reactions at surfaces by transient IR spectroscopies; ii) apply these tools to investigate the heterogeneity of structural and solvation environments and differences in dynamic fluctuations imposed by the interface depending on its nature, morphology, charge and surrounding chemical entities; iii) establish the impact of the nature of the interface and its correlation length on the chemical reactivity of chemisorbed molecules; iv) influence the rate and possibly the product of these reactions by tailored electric fields emanating from the interface. State-of-the-art multidimensional IR spectroscopy is the primary tool to achieve these goals in combination with complementary surface preparation and characterization techniques, electrochemistry, computer simulations, and ultrafast electronic methods. The expected end result is a widely applicable versatile surface dynamics tools capable of investigating various physical and chemical processes at complex interfaces, in addition to a detailed picture of structural dynamics of several target molecules and the ability to catalyze/inhibit their photoreactions and possibly change the nature or yield of their products. The impact of these results is expected to paint the dynamic picture of surface processes with atomistic structural details. Revelation of the intrinsic dynamics of liquids next to the electrocatalytic surface, the structural and dynamic effects of the ions situated in the electric double layer and understanding of the solid-electrolyte interphase region are invaluable pieces of information that bear direct implications for the basic science and technology. They are expected to influence the strategies and approaches for the design and development of new battery and supercapacitor technologies, improve photo- and electrocatalytic processes and enhance the fundamental knowledge about the boundary between solid and liquid. The results of the nonequilibrium experiments at electrified interfaces transcend the boundaries of the surface science and can potentially demonstrate the practical feasibility of the concept of the electrostatic catalysis and control of chemical reactions on a macroscopic scale.
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