Combined Atomic Imaging and Diffraction Studies of the Electrooxidation of Supported Metal Multilayers

Lead Research Organisation: University of Liverpool
Department Name: Physics


The solid/liquid interface plays a fundamental role in a diverse range of physical phenomena, for example in catalysis, crystal growth and in many biological reactions that govern the building of the human body and the functioning of the brain. Unravelling the atomic structure at the solid/liquid interface remains, therefore, one of the major challenges facing surface science today for it is only by understanding the physical processes in model systems that we can extrapolate to more complex environments. The key to developing this understanding lies in the preparation and study of model surfaces with well-defined elemental reaction sites.The development of alternative methods of energy supply and storage requires major advances in materials research. Such advances may now be achieved by the manipulation of molecular and atomic-scale processes, leading to an increased understanding of the physical and chemical properties of new materials. In particular, design of these materials may become possible from fundamental principles, i.e. understanding surface properties, as distinct from the bulk material properties, by the application of modern experimental techniques. The aims of this proposal are to further the understanding of the atomic and electronic structure at the electrochemical interface particularly to develop a fundamental understanding of the oxidation and reduction of transition metal multilayer films deposited by electrochemical methods. Due to the buried nature of the electrochemical interface, it is inaccessible to most standard surface science techniques that employ strongly adsorbed electron probes to gain surface sensitivity. Study of the interface is restricted to techniques that employ penetrating radiation, such as x-ray scattering or to imaging techniques such as scanning tunneling microscopy (STM) and atomic force microscopy (AFM). The utilization of synchrotron radiation facilities (the European Synchrotron Radiation Facility in Grenoble and the Diamond Light Source at the Rutherford Appleton Laboratory) is a key component of this project. They offer state-of-the-art equipment for performing x-ray scattering experiments with high incident x-ray flux, energy tuneability and high resolution. Using such equipment it will be possible to probe surface atomic structure and the structures of adsorbed species with sub-monolayer resolution and also to gain electronic structure information from selected interface atoms that form the boundary between the solid surface and the liquid electrolyte where electric field driven reactions occur. By combining x-ray scattering (reciprocal space information) and imaging techniques (real space information) it will be possible to build a detailed picture of a surface structure under 'real' working conditions.


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Description The research focused on the preparation of supported metal monolayers produced by electrodeposition methods. The aim was to prepare supported monolayers in order to study processes such as oxidation and electrochemical reactions. Some of the results are still being processed and prepared for publication.
Key findings so far are:
(1) New insight into ordering into the structure of the electrochemical double layer (the liquid side of the interface) and the influence of this structure on electrochemical reactivity.
(2) The influence of surface alloys on electrocatalytic reactions, such as the oxygen reduction reaction.
(3) Fundamental insight into the nature of bonding in metal-halide structures, ie structure and charge transfer.
Exploitation Route The results obtained have advanced the fundamental understanding of the structure at the electrochemical interface and also the knowledge of applying modern synchrotron x-ray techniques to probe atomic structure at the electrochemical interface. The results will be used by other researchers in the field along with scientists developing methodologies at central facilities such as the Diamond Light Source and ESRF.
2 new publications associated with this project have been submitted in 2016. One has been accepted for publication and the other is under review.
Sectors Chemicals,Energy,Environment