Abstract
The development of three-way catalysts with improved low temperature activity is essential for automotive catalysis. Here, we show that solution atomic layer deposition (SALD) of titania or zirconia promoters on alumina supports lowers the light-off temperatures of rhodium-based catalysts by 50–150 °C compared to a commercial benchmark three-way catalyst. X-ray diffraction, scanning transmission electron microscopy–electron energy loss spectroscopy, diffuse reflectance UV–visible spectroscopy and X-ray absorption near edge structure results indicate that titania incorporated by SALD at one monolayer loading is present primarily as atomically disperse 5-coordinate Ti4+ species. These species persist after exposure to steam and corrosive gases at temperatures up to 960 °C. Zirconia incorporated onto alumina by SALD is present as few-nanometre oxide particles and supports a three-way catalyst activity that is superior to that of Rh on either alumina or zirconia. Our results show that molecularly precise synthesis can lead to robust promotion of precious metal activity and provide a promising path towards reducing emissions from gasoline vehicles.
| Original language | English |
|---|---|
| Pages (from-to) | 614-622 |
| Number of pages | 9 |
| Journal | Nature Catalysis |
| Volume | 2 |
| Issue number | 7 |
| DOIs | |
| State | Published - Jul 1 2019 |
Funding
This research was sponsored by the US Department of Energy, Office of Energy Efficiency and Renewable Energy, Vehicle Technologies Office, Propulsion Materials Program under grant no. DE-EE0006845. Electron microscopy on the FEI Talos F200X STEM was provided by the Department of Energy, Office of Nuclear Energy, Fuel Cycle R&D Program and the Nuclear Science User Facilities. This research used resources of the Materials Research Collaborative Access Team at the Advanced Photon Source, a US Department of Energy Office of Science User Facility operated for the DOE by Argonne National Laboratory under contract no. DE-AC02-06CH11357. The authors thank K. Nietering for assistance with diffuse reflectance UV–vis spectroscopy, J. Wu and J. Kropf for assistance with X-ray absorption spectroscopy, and J. Hepburn, T. Toops, A. Binder, E. Kyriakidou, J. Schwank, G. Fisher, J. Hoard and C.-Y. Seo for useful discussions. This manuscript was co-authored by UT-Battelle, LLC, under contract no. DE-AC05-00OR22725 with the US Department of Energy (DOE).