Abstract
Copper exchanged chabazites are among the state-of-the-art catalyst materials being studied for selective catalytic reduction of NOx, however, there is still a need to understand how these materials store ammonia after aging. In this work, studies are performed to assess the ammonia storage capacity of Cu-SSZ-13 as a function of concentration, temperature, and extent of hydrothermal aging. Ammonia binds at three difference sites: (i) a Cu site bound at 1 framework Al (Z1Cu site), (ii) a Cu site bound at 2 framework Al (Z2Cu site), and (iii) a Brønsted acid site (ZH site). Results show that a 3-site model can accurately capture ammonia storage across all conditions. Impacts for hydrothermal aging are considered via 3 aging reactions that change the site densities of each identified adsorption site. Model assessment shows that during aging there is a significant loss in Brønsted acid sites.
| Original language | English |
|---|---|
| Article number | 120898 |
| Journal | Applied Catalysis B: Environmental |
| Volume | 303 |
| DOIs | |
| State | Published - Apr 2022 |
Funding
This manuscript has been authored by UT-Battelle, LLC under Contract No. DE-AC05–00OR22725 with the U.S. Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan (http://energy.gov/downloads/doe-public-access-plan). This research was supported by the DOE Office of Energy Efficiency and Renewable Energy (EERE), Vehicle Technologies Office and used resources at the National Transportation Research Center, a DOE-EERE User Facility at Oak Ridge National Laboratory. We appreciate the guidance of Siddiq Khan, Ken Howden, and Gurpreet Singh at DOE VTO and helpful discussions with our colleagues at the ORNL NTRC. We also thank the editors and reviewers for their support and volunteered time. We dedicate this manuscript to the memory of C. Stuart Daw, an outstanding researcher and mentor who led this work during its early stages. Notice:, This manuscript has been authored by UT-Battelle, LLC under Contract No. DE-AC05?00OR22725 with the U.S. Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan (http://energy.gov/downloads/doe-public-access-plan). This research was supported by the DOE Office of Energy Efficiency and Renewable Energy (EERE), Vehicle Technologies Office and used resources at the National Transportation Research Center, a DOE-EERE User Facility at Oak Ridge National Laboratory. We appreciate the guidance of Siddiq Khan, Ken Howden, and Gurpreet Singh at DOE VTO and helpful discussions with our colleagues at the ORNL NTRC. We also thank the editors and reviewers for their support and volunteered time.
Keywords
- Aging
- Ammonia storage
- Copper chabazite
- Modeling
- Selective catalytic reduction