第122回先端計測オープンセミナー

2018年4月11日 (水) 10:00-11:00

国立研究開発法人 物質・材料研究機構
千現地区 研究本館8階 中セミナー室
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Prof. Ludo B.F. Juurlink (Leiden Institute of Chemistry , Leiden University)

Fundamental studies on the influence of defects and coadsorbates on adsorption of H₂O and H₂ on platinum

Defects have been known to alter the chemical reactivity of surfaces [1, 2]. While theoretical studies predict trends [3], systematic experimental studies for nanostructured surfaces are sparse.

To start, I review our results on the influence of surface structure on the adsorption of H₂O on platinum obtained using a series of Pt single crystals. I discuss how the two most common step types influence the adsorption of water and address how H_ads and O_ads alter the interaction.

Subsequently, I discuss how curved single crystal surfaces allow for probing the influence of different types of defects with a continuous variation of defect density. We use STM and LEED, AES, TPD, RAIRS, and SMB techniques to study them with varying degrees of spatial resolution[4]. I show how it allows us to unravel fundamental problems in catalysis using H₂ dissociation on platinum [5-6] as an example.

References
[1] S.L. Rernasek, W.J. Siekhaus and G.A. Somorjai, Phys.Rev.Lett. 30, 1202 (1973)
[2] L. Vattuonea, L. Savioa, Ma.Rocca, Surf. Sci. Rep. 63, 101 (2008)
[3] J.K. Norskov et al. J. Catal. 209, 275 (2002)
[4] C. Hahn et al. J. Chem. Phys. 136, 114201 (2012); Mom et al., Surf. Sci. 615, 015 (2013); Janlamool et al., Molecules 19, 10845 (2014); Walsh et al., J. Vac. Sci. Technol A 35, 03E102 (2017)
[5] B. Poelsema, K. Lenz, and G. Comsa, J. Chem. Phys. 134, 074703 (2011); ibid. J. Phys. Condens. Matter 22, 304006 (2010).
[6] A. T. Gee et al., J. Phys. Chem. 112, 7660 (2000); D.A. McCormack et al. J. Chem. Phys. 122, 194708 (2005); I.M.N. Groot et al. J. Phys. Chem. C 117, 9266 (2013)