Dresden 2011 – scientific programme

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O: Fachverband Oberflächenphysik

O 12: Metal substrates: Adsorption of O / H and inorganic molecules I

O 12.2: Talk

Monday, March 14, 2011, 15:15–15:30, WIL A317

Adsorption and reaction of sulfurdioxide on clean and oxygen precovered Pd(100) — •Karin Gotterbarm, Regine Streber, Christian Papp, Oliver Höfert, Michael Peter Andreas Lorenz, and Hans-Peter Steinrück — Lehrstuhl für physikalische Chemie II, Universität Erlangen-Nürnberg, Egerlandstr. 3, 91052 Erlangen

Sulfur and its oxides are well-known poisons in large scale applications of heterogeneously catalyzed reactions. We studied the adsorption and thermal evolution of SO₂ on a clean and oxygen precovered Pd(100) surface by in-situ high-resolution XPS applying synchrotron radiation at BESSY II, Berlin. Adsorption of SO₂ on the clean Pd(100) surface at 130 K leads to formation of two different SO₂ species: a highly populated upright standing SO₂ species and a small amount of flat lying SO₂. Upon annealing the sample standing SO₂ is transformed into lying SO₂, which is ultimately reduced to atomic sulfur. On the oxygen precovered surface a fraction of SO₂ reacts to SO₃ immediately upon adsorption, even at temperatures as low as 130 K. Heating of the resulting mixed adsorbate layers first results in the conversion of all remaining SO₂ species to SO₃ followed by subsequent oxidation to SO₄ above 300 K.

This work was supported by the BMBF under grant 05 ES3XBA/5 and by the Cluster of Excellence ’Engineering of Advanced Materials’.