Regensburg 2010 – wissenschaftliches Programm
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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”.