Catalyst Preparation Using Controlled Pt deposition onto well-
defined CeO2 nanostructures using Atomic Layer Deposition
Haibin Zheng, Lilli Eleanor Carpo, Helena Hagelin-Weaver
University of Florida, Gainesville, U.S.A.
In recent years, ceria-supported catalysts have been studied extensively, mainly due to the oxygen storage capacity (OCS) of ceria and its ability to induce strong metal-support interactions. Many studies have been performed over CeO2-supported catalysts and suggest that the metal-support interface plays an important role during the redox reactions. In an attempt to facilitate determining structure-activity relationships and comparisons to theoretical studies, we prepare well-defined catalysts by supporting active metals onto CeO2 nanoshapes. The benefit of using well-defined CeO2 nanoshapes is that CeO2 nano-octahedra have a (1 1 1) surface termination, while the CeO2 nano-rods consist of (1 0 0) and (1 1 0) surface facets. Thus, the CeO2 nanoshapes allow us to investigate the effects of CeO2 surface facets on the active metal, such as platinum. To obtain better control over the active metal deposition, compared with conventional catalyst preparation techniques, we used atomic layer deposition of platinum onto the CeO2 nanoshapes. Early results demonstrate that the sizes and the amount of the Pt nanoparticles can be fine-tuned by adjusting the ALD conditions (such as deposition temperature and time, as well as number of ALD cycles). Moreover, preliminary CO oxidation data over the prepared catalysts reveal that the support structure can strongly influence not only the Pt deposition, but also the catalytic actives. Characterizations of these catalysts are underway to obtain a better understanding of the metal-support interactions of these catalysts.
Figure 1: Pt deposited onto CeO2 nano-rod and nano-octahedra using ALD