Surface X-ray Diffraction Studies of the Metal-Electrolyte Interface

McIntyre, Thomas (2025) Surface X-ray Diffraction Studies of the Metal-Electrolyte Interface PhD thesis, University of Liverpool.

Text 201119913_Sep2024.pdf - Author Accepted Manuscript Download (16MB) | Preview

Abstract

Interfacial electrochemistry is fundamental to the development of electrocatalytic renewable energy technologies such as fuel cells, batteries and carbon capture systems. Although vast amounts of resources are applied to the fabrication and characterisation of electrocatalysts, for technologies such as these to be viable on a large scale and mitigate the effects of anthropogenic climate change, a better fundamental understanding of the atomic and electronic structure of the electrochemical interface is required. This thesis presents the results of a series of experiments employing surface X-ray diffraction (SXRD) of the electrochemical interface of fcc(111) metal surfaces. First presented is an SXRD study of Cu(111) and Ag(111) surfaces in varying concentrations of aqueous acetonitrile-containing electrolyte. The study shows evidence of a combination of potential-induced dissolution and re-adsorption of surface metal layers and formation of surface metal oxides, and a roughening of the metal surface with increasing concentrations of acetonitrile, demonstrating the dramatic effect that acetonitrile can have on transition metal surfaces without being specifically adsorbed. A study of thin cobalt films electrodeposited on Au(111) surfaces is also presented, where energy-dispersive resonant SXRD measurements reveal subtle changes in the RSXRD spectrum at the cobalt K edge depending on the thickness of the thin film and the applied electric field, providing foundational information on the underlying physical mechanism behind the favourable magneto-electric properties of thin Co films. Lastly presented is a study of the cation contribution to the structure of the electrochemical interface, consisting of measurements of Pt(111) and Au(111) in aqueous cesium hydroxide (CsOH) electrolyte. The study employs SXRD to construct a model of the electrochemical interface, combined with resonant SXRD and XAS measurements. Results suggest a hydrated Cs layer ordered in the plane of the surface on Pt(111), while measurements on Au(111) suggest a more disordered Cs layer. The experimental work detailed in this thesis, performed over a series of experimental sessions at synchrotron facilities (the i07 beam line at Diamond Light Source, Didcot, UK, the XMaS beamline at the ESRF, Grenoble, and the Advanced Photon Source, Illinois), represents a significant contribution to our understanding of the electrochemical interface, demonstrating the power and versatility of SXRD and providing foundational information for the development and refinement of vital electrochemical technologies.

Item Type:	Thesis (PhD)
Uncontrolled Keywords:	acetonitrile, ag(111), au(111), cobalt, csoh, cu(111), electrocatalysis, electrochemistry, pt(111), resonant surface x-ray diffraction, surface x-ray diffraction, sxrd, thin film electrochemistry, x-ray
Divisions:	Faculty of Science & Engineering Faculty of Science & Engineering > School of Physical Sciences
Depositing User:	Symplectic Admin
Date Deposited:	21 Aug 2025 08:01
Last Modified:	21 Aug 2025 08:03
DOI:	10.17638/03190962
Supervisors:	Lucas, Christopher McGrath, Ronan
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3190962
Disclaimer:	The University of Liverpool is not responsible for content contained on other websites from links within repository metadata. Please contact us if you notice anything that appears incorrect or inappropriate.