LAUSR

Supported gold catalysts are highly active for a variety of reactions including low-temperature CO oxidation. It has been shown that reducible support materials, e.g. ceria or titania, may significantly alter the catalytic performance. In this contribution, we provide the first direct evidence for ceria (CeO2) support dynamics and its relevance in Au/CeO2 catalysts during room temperature CO oxidation. In particular, combined operando Raman and UV-Vis spectroscopy are employed to monitor the surface and subsurface defect dynamics of ceria quantitatively and in real time. The results clearly show a dependence of catalytic activity on the reduction state of the ceria support. In fact, the pre-reduced CeO2 catalyst support increases the activity during CO oxidation initially by 100%. The reduction is not limited to the CeO2 surface but also affects the CeO2 subsurface due to oxygen mobility and charge transfer in CeO2-x. Our results highlight the enormous importance of the support properties for a mechanisti...