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Regensburg 2010 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 41: Poster Session I (Semiconductor Substrates: Epitaxy and growth; Semiconductor Substrates: Adsorbtion; Semiconductor Substrates: Solid-liquid interfaces; Semiconductor Substrates: Clean surfaces; Oxides and insulators: Epitaxy and growth; Oxides and insulators: Adsorption; Oxides and insulators: Clean surfaces; Organic, polymeric and biomolecular films - also with adsorbates; Organic electronics and photovoltaics, Surface chemical reactions; Heterogeneous catalysis; Phase transitions; Particles and clusters; Surface dynamics; Surface or interface magnetism; Electron and spin dynamics; Spin-Orbit Interaction at Surfaces; Electronic structure; Nanotribology; Solid/liquid interfaces; Graphene; Others)

O 41.28: Poster

Dienstag, 23. März 2010, 18:30–21:00, Poster B1

First-principles study of the interaction of CO, CO2 and water with NiO surfaces — •Tobias Schaub, Volker Strauss, and Bernd Meyer — Interdisziplinäres Zentrum für Molekulare Materialien ICMM, Universität Erlangen-Nürnberg

Nickel oxide is an important catalyst for the cracking and partial oxidation of hydrocarbons. Under reaction conditions CO, CO2 and water are frequently present in the gas phase. The formation of carbonates and the partial hydroxylation of the NiO surfaces, however, often leads to a reduction of the catalytic activity of NiO due to a blocking of available surface sites for the hydrocarbon reactions. To elucidate the nature and stability of the surface carbonates and hydroxyl groups we have used DFT+U calculations to study the adsorption of CO, CO2 and water on different structural models of ideal and defective NiO surfaces. We find that undercoordinated Ni sites activate CO2 and stable surface carbonates are formed which are bound in a tridentate configuration, similar as previously observed for ZnO [1]. Water adsorbs molecularly or dissociatively, depending on the surface sites with a similar binding energy as CO2. Therefore, a strong competition between CO2 and water for the low coordinated Ni surface sites can be expected. Finally, the influence of O vacancies on the adsorption of CO, CO2 and water will be discussed.

[1] Y. Wang et al. Angew. Chem. Int. Ed. 46 (2007) 5624

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