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O: Fachverband Oberflächenphysik

O 12: Oxides and insulators: Adsorption

O 12.8: Vortrag

Montag, 22. März 2010, 16:45–17:00, H33

Interaction of CO₂ and H₂O with Thin NiO Layers on Cu(111) — •Karin Gotterbarm, Michael Peter Andreas Lorenz, Regine Streber, Oliver Höfert, Marie-Madeleine Walz, Christian Papp, Andreas Bayer, and Hans-Peter Steinrück — Lehrstuhl für Physikalische Chemie II, Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058 Erlangen

NiO is an important material in heterogeneous catalysis. Under ambient conditions, reactions with CO₂ and H₂O can lead to the formation of carbonates and hydroxides, which could block active sites and thereby influence the catalytic reactivity. We studied the adsorption of CO₂ and H₂O on thin NiO layers (around 2 ML) on Cu(111) as inert substrate by in-situ XPS applying synchrotron radiation at BESSY II.

Upon adsorption of CO₂, characteristic peaks in the O 1s and C 1s region indicate the formation of carbonate. When the surface is exposed to water, hydroxide and multilayers of water are formed. In-situ XPS during heating revealed an unusual thermal stability of the carbonate as well as hydroxide layers. Experiments on different NiO layers with varying hydroxide precoverages showed that adsorbed OH species effectively block CO₂ adsorption sites, leading to a lower saturation coverage of CO₃.

This work was supported by BMBF (05 ES3XBA/5) and the DFG through the Cluster of Excellence ”Engineering of Advanced Materials”.