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Surface Science Group

 

The group's research activities can be grouped under four main themes:

Complex Interadsorbate Interactions

Interadsorbate interactions may be broadly categorised as arising due to either through-space mechanisms or substrate-mediated phenomena. Although they are most often repulsive in character, a classic example of important attractive interactions is the formation of extended hydrogen-bonded networks on the surface, found in the adsorption of water, amino acids, and other biologically-relevant molecules. Unexpected attractive interaction is also found in the stable coadsorption of NO2 and CO (two electronegative species) on Au{111}. We aim to study these and other systems, in which the interadsorbate interactions are both important and far from simple.

Nanoscale Surface Phenomena

Behaviour at the nanoscale cannot be extrapolated from knowledge of macroscopic properties; the only productive strategy is from the bottom up (i.e. a rigorous investigation at the atomistic level). In this context, the group has developed a new approach to the understanding of surface structure and symmetry, which provides a new perspective on the issues surrounding facetted and/or rough roughened surfaces. These ideas feed through to the interpretation of experiments, for example our STM work on the atomically rough and/or facetted reconstructions of Pt{531} and Cu{531} surfaces. We also maintain an interest in surface nanomagnetism, in particular relating to the deposition of magnetic overlayers on stepped and kinked substrates.

Tuning Reactivity and Catalysis

Catalytic processes can be tuned by means that are either predominantly electronic (e.g. alloying, promotion), predominantly structural (e.g. nanoparticles, stepped surfaces), or a mixture of both (e.g. oxide supports with strong interactions). From a theoretical point of view, our group has contributed to the development of coinage metal systems for low-temperature catalysis, fungiform nanostructures of Au/IrO2/TiO2, and the water-gas-shift reaction on ceria-supported Au nanoclusters. We have also suggested safer and more efficient means to produce synthesis gas from natural gas, as a feedstock for Fischer-Tropsch or other C-C coupling reactions, both through experiment and theory.

Chiral Surface Systems

Surfaces can possess the property of chirality - that is, exist in two non-superimposable mirror-image forms - and such surfaces have the capability of directing physical or chemical phenomena to occur in an asymmetric manner. This can be achieved by adsorption of chiral modifiers or (less frequently) by the use of intrinsically chiral surfaces. In particular, kink-free chiral surfaces (only achievable in bcc substrates) are expected to be stable against roughening, and should therefore provide excellent substrates for detailed studies of asymmetric surface chemistry. We focus on the adsorption of simple chiral and prochiral molecules on achiral and chiral substrates, with a view towards demonstrating asymmetric effects.