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Fundamental Research into Understanding the Molecular structure of eleKtrochemical INterfaces

Project description

Enhancing models of processes at the electrode–electrolyte interface

Meeting the growing energy demand in a sustainable way is one of the biggest challenges of our time. The electrode–electrolyte interface is a critical component of many energy storage and energy generation devices. It is here that charge transfer, electrolyte decomposition and electrode degradation take place. As ions from the electrolyte solution adhere to the surface of the electrode, separated from the charges in the electrode itself, a so-called electric double layer is formed. This structure plays a critical role in electrochemical and electrocatalytic reactions. Through a comprehensive combination of experimental, theoretical and computational techniques, the EU-funded FRUMKIN project is developing a new model of processes occurring at the electric double layer.

Objective

The FRUMKIN project aims to develop and test a new model for the electric double-layer structure of the electrode-electrolyte interface and to investigate the impact of this double-layer structure on the kinetics and selectivity of electrochemical and electrocatalytic reactions. The inspiration for this new model comes from my own recent work that the classical Gouy-Chapman-Stern model for the electric double layer fails to properly describe the interface between an aqueous electrolyte and single-crystal platinum and gold electrodes. Specifically, our results indicate that there is an attractive interaction between ions and the electrode surface (unaccounted for in the Gouy-Chapman-Stern theory) that accumulates ions in the diffuse double layer, and that ions in the double layer interact with the electrode and with themselves through water-mediated hydration forces, approximately following the Hofmeister series. These effects are observed even for low electrolyte concentrations, explaining the invalidity of the Gouy-Chapman-Stern theory.
The FRUMKIN project will approach its research objectives using a variety of high-level experimental, spectroscopic, theoretical, and computational techniques. The heart of the experimental work is based on ac voltammetry, i.e. differential capacitance measurements of the various interfaces, and electrochemical measurements of reactivity. Modelling of the experimental differential capacitance curves is based on first-principles DFT calculations and coarse-grained free-energy-based classical density functional simulations of the double-layer properties. Experimental molecular details of both double-layer structure and reactivity will be obtained from in situ vibrational spectroscopy (Infrared and Raman) and advanced in situ X-Ray spectroscopy, specifically Near-Ambient Pressure X-Ray Photoelectron Spectroscopy and Total Electron Yield X-Ray Absorption Spectroscopy.

Host institution

UNIVERSITEIT LEIDEN
Net EU contribution
€ 2 500 000,00
Address
RAPENBURG 70
2311 EZ Leiden
Netherlands

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Region
West-Nederland Zuid-Holland Agglomeratie Leiden en Bollenstreek
Activity type
Higher or Secondary Education Establishments
Links
Total cost
€ 2 500 000,00

Beneficiaries (1)