Divergent influence of {1 1 1} vs. {1 0 0} crystal planes and Yb3+ dopant on CO oxidation paths in mixed nano-sized oxide Au/Ce1−xYbxO2−x/2 (x = 0 or 0.1) systems

Abstract

In this paper, the fundamental information on interactions in systems concerning nanocrystalline gold disperses on the shaped (octahedron-like or cube-like) Ce_1−xYb_xO_2−x/2 (x = 0 or 0.1) support has been discussed. Four types of Au/Ce_1−xYb_xO_2−x/2 systems with different morphology and defect level of support have been investigated. It was observed that the microstructure and structural features of the support crystals play a key role in the reaction of CO oxidation catalysed by Au/Ce_1−xYb_xO_2−x/2 materials. The divergent influence of Yb³⁺ dopant on the CO reaction as a function of exposing planes of the support was observed for Ce_1−xYb_xO_2−x/2 and Au/Ce_1−xYb_xO_2−x/2 systems. For the undecorated oxides, the presence of Yb³⁺ ions in the ceria matrix increased the activity of the octahedron-like oxides, but decreased it for the cube-like ones. On the other hand, the positive effect of the Yb-dopant on the reactivity of Au/Ce_1−xYb_xO_2−x/2 systems was observed for both morphologies.