A Thermodynamic Investigation of Ni on Thin-Film Titanates (ATiO<sub>3</sub>)
Thin, ~1-nm films of CaTiO<sub>3</sub>, SrTiO<sub>3</sub>, and BaTiO<sub>3</sub> were deposited onto MgAl<sub>2</sub>O<sub>4</sub> by Atomic Layer Deposition (ALD) and then studied as catalyst supports for ~5 wt % of Ni that was added to th...
| Main Authors: | , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2020-12-01
|
| Series: | Inorganics |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2304-6740/8/12/69 |
| _version_ | 1797544951675879424 |
|---|---|
| author | Chao Lin Alexandre C. Foucher Eric A. Stach Raymond J. Gorte |
| author_facet | Chao Lin Alexandre C. Foucher Eric A. Stach Raymond J. Gorte |
| author_sort | Chao Lin |
| collection | DOAJ |
| description | Thin, ~1-nm films of CaTiO<sub>3</sub>, SrTiO<sub>3</sub>, and BaTiO<sub>3</sub> were deposited onto MgAl<sub>2</sub>O<sub>4</sub> by Atomic Layer Deposition (ALD) and then studied as catalyst supports for ~5 wt % of Ni that was added to the perovskite thin films by Atomic Layer Deposition. Scanning Transmission Electron Microscopy demonstrated that both the Ni and the perovskites uniformly covered the surface of the support following oxidation at 1073 K, even after redox cycling, but large Ni particles formed following a reduction at 1073 K. When compared to Ni/MgAl<sub>2</sub>O<sub>4</sub>, the perovskite-containing catalysts required significantly higher temperatures for Ni reduction. Equilibrium constants for Ni oxidation, as determined from Coulometric Titration, indicated that the oxidation of Ni shifted to lower <inline-formula><math display="inline"><semantics><mrow><msub><mi>P</mi><mrow><msub><mi>O</mi><mn>2</mn></msub></mrow></msub></mrow></semantics></math></inline-formula> on the perovskite-containing materials. Based on Ni equilibrium constants, Ni interactions are strongest with CaTiO<sub>3</sub>, followed by SrTiO<sub>3</sub> and BaTiO<sub>3</sub>. The shift in the equilibrium constant was shown to cause reversible deactivation of the Ni/CaTiO<sub>3</sub>/MgAl<sub>2</sub>O<sub>4</sub> catalyst for CO<sub>2</sub> reforming of CH<sub>4</sub> at high CO<sub>2</sub> pressures, due to the oxidation of the Ni. |
| first_indexed | 2024-03-10T14:08:46Z |
| format | Article |
| id | doaj.art-57968c13ba4a48af88c08fc9b7f76929 |
| institution | Directory Open Access Journal |
| issn | 2304-6740 |
| language | English |
| last_indexed | 2024-03-10T14:08:46Z |
| publishDate | 2020-12-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Inorganics |
| spelling | doaj.art-57968c13ba4a48af88c08fc9b7f769292023-11-21T00:24:51ZengMDPI AGInorganics2304-67402020-12-018126910.3390/inorganics8120069A Thermodynamic Investigation of Ni on Thin-Film Titanates (ATiO<sub>3</sub>)Chao Lin0Alexandre C. Foucher1Eric A. Stach2Raymond J. Gorte3Department of Chemical and Biomolecular Engineering, University of Pennsylvania, 34th Street, Philadelphia, PA 19104, USADepartment of Materials Science and Engineering, University of Pennsylvania, Philadelphia, PA 19104, USADepartment of Materials Science and Engineering, University of Pennsylvania, Philadelphia, PA 19104, USADepartment of Chemical and Biomolecular Engineering, University of Pennsylvania, 34th Street, Philadelphia, PA 19104, USAThin, ~1-nm films of CaTiO<sub>3</sub>, SrTiO<sub>3</sub>, and BaTiO<sub>3</sub> were deposited onto MgAl<sub>2</sub>O<sub>4</sub> by Atomic Layer Deposition (ALD) and then studied as catalyst supports for ~5 wt % of Ni that was added to the perovskite thin films by Atomic Layer Deposition. Scanning Transmission Electron Microscopy demonstrated that both the Ni and the perovskites uniformly covered the surface of the support following oxidation at 1073 K, even after redox cycling, but large Ni particles formed following a reduction at 1073 K. When compared to Ni/MgAl<sub>2</sub>O<sub>4</sub>, the perovskite-containing catalysts required significantly higher temperatures for Ni reduction. Equilibrium constants for Ni oxidation, as determined from Coulometric Titration, indicated that the oxidation of Ni shifted to lower <inline-formula><math display="inline"><semantics><mrow><msub><mi>P</mi><mrow><msub><mi>O</mi><mn>2</mn></msub></mrow></msub></mrow></semantics></math></inline-formula> on the perovskite-containing materials. Based on Ni equilibrium constants, Ni interactions are strongest with CaTiO<sub>3</sub>, followed by SrTiO<sub>3</sub> and BaTiO<sub>3</sub>. The shift in the equilibrium constant was shown to cause reversible deactivation of the Ni/CaTiO<sub>3</sub>/MgAl<sub>2</sub>O<sub>4</sub> catalyst for CO<sub>2</sub> reforming of CH<sub>4</sub> at high CO<sub>2</sub> pressures, due to the oxidation of the Ni.https://www.mdpi.com/2304-6740/8/12/69Atomic Layer DepositionNi catalystreforming catalystthermodynamics |
| spellingShingle | Chao Lin Alexandre C. Foucher Eric A. Stach Raymond J. Gorte A Thermodynamic Investigation of Ni on Thin-Film Titanates (ATiO<sub>3</sub>) Inorganics Atomic Layer Deposition Ni catalyst reforming catalyst thermodynamics |
| title | A Thermodynamic Investigation of Ni on Thin-Film Titanates (ATiO<sub>3</sub>) |
| title_full | A Thermodynamic Investigation of Ni on Thin-Film Titanates (ATiO<sub>3</sub>) |
| title_fullStr | A Thermodynamic Investigation of Ni on Thin-Film Titanates (ATiO<sub>3</sub>) |
| title_full_unstemmed | A Thermodynamic Investigation of Ni on Thin-Film Titanates (ATiO<sub>3</sub>) |
| title_short | A Thermodynamic Investigation of Ni on Thin-Film Titanates (ATiO<sub>3</sub>) |
| title_sort | thermodynamic investigation of ni on thin film titanates atio sub 3 sub |
| topic | Atomic Layer Deposition Ni catalyst reforming catalyst thermodynamics |
| url | https://www.mdpi.com/2304-6740/8/12/69 |
| work_keys_str_mv | AT chaolin athermodynamicinvestigationofnionthinfilmtitanatesatiosub3sub AT alexandrecfoucher athermodynamicinvestigationofnionthinfilmtitanatesatiosub3sub AT ericastach athermodynamicinvestigationofnionthinfilmtitanatesatiosub3sub AT raymondjgorte athermodynamicinvestigationofnionthinfilmtitanatesatiosub3sub AT chaolin thermodynamicinvestigationofnionthinfilmtitanatesatiosub3sub AT alexandrecfoucher thermodynamicinvestigationofnionthinfilmtitanatesatiosub3sub AT ericastach thermodynamicinvestigationofnionthinfilmtitanatesatiosub3sub AT raymondjgorte thermodynamicinvestigationofnionthinfilmtitanatesatiosub3sub |