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Aromatic adsorption on metal surfaces plays a key role in many fields including heterogeneous catalysis, electrochemical devices, photovoltaics, corrosion protection and chemical sensing. As the simplest aromatic molecule, benzene has been widely studied on a variety of metal surfaces both computationally and experimentally.1-3 However, one metal surface which has received very little attention in this context is iron. Experimental UHV adsorption studies carried out on iron surfaces are complicated by the metal's reactivity and strong tendency to passivate, which result in significant difficulty obtaining a high purity metal surface. Still, iron is deserving of study as it is the major component of steel and catalyses important industrial reactions such as the Fischer-Tropsch and Haber processes. Computational studies of the surface chemistry of benzene and other aromatic molecules on iron provides novel insight on these system as well as a level of detail which would not be afforded using experimental techniques.

The density functional theory (DFT) studies carried out at present are conducted on the three most stable surface facets of bcc iron, including flat {110}, kinked {100} and stepped {211}. To support the energetic and geometric results obtained using periodic DFT calculations, charge density differences, residual spin densities, density of states (DOS) and work function changes can also be calculated and analysed. Finally, the effect of van der Waals corrected DFT on binding site energetics and geometries is being studied using the Tkatchenko-Scheffler (TS) correction.4 Such corrections have been shown to provide results in better agreement with experiment for aromatic adsorption on certain metal surfaces.1

We also have carried out DFT work on industrially important Fe-related surfaces such as Fe sulphides and carbides.

 

[1] Carrasco, J., Liu, W., Michaelides, A., Tkatchenko, A. J. Chem. Phys. 2014, 140, 084704

[2] Jenkins, S. J. Proc. R. Soc. A 2009, 465(2110), 2949-2976

[3] Netzer, F. P. Langmuir 1991, 7(11), 2544-2547

[4] Tkatchenko, A., Scheffler, M. Phys. Rev. Lett. 2009, 102(7), 073005

 

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