Abstract
The oxygen vacancy structure of ceria plays a key role in its performance as a favored material for catalysis applications. Here, we develop an understanding of the effects of Pt loading on the structural evolution of ceria nanorods under redox gas environments that mimic real automotive catalytic converters. In situ neutron scattering studies under redox flow reveal that both CeO2 and Pt-CeO2 nanorods share a bulk fluorite structure with the presence of surface Frenkel-type oxygen defects. However, Pt-CeO2 nanorods are more easily reducible than CeO2 rods as evidenced by an increased concentration of Ce3+, determined by NAP-XPS. Importantly, this work finds no evidence of oxygen vacancy ordered surface reconstruction which has been reported in earlier ex situ investigations. Thus, this work highlights the discrepancy between ex situ and in situ structural observations and emphasizes the need for robust in situ investigations of catalysts to develop industrially relevant materials.
| Original language | English |
|---|---|
| Pages (from-to) | 3689-3697 |
| Number of pages | 9 |
| Journal | Journal of Physical Chemistry C |
| Volume | 127 |
| Issue number | 7 |
| DOIs | |
| State | Published - Feb 23 2023 |
Funding
This work was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences Early Career Research Program Award KC040602, under Contract DE-AC05-00OR22725. Data analysis and interpretation was supported by the Graduate Advancement and Training Education fellowship and sponsored by the Science Alliance. Sample preparation was supported as part of UNCAGE-ME, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science (Basic Energy Sciences), under Award DE-SC0012577. This research used beamline BL-1B (NOMAD) at the Spallation Neutron Source, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory.