| dc.date.accessioned | 2022-10-06T14:44:52Z | |
| dc.date.available | 2022-10-06T14:44:52Z | |
| dc.date.issued | 2022 | |
| dc.identifier.uri | http://hdl.handle.net/10852/97026 | |
| dc.description.abstract | One of the steps in the production of synthetic nitrogen-based fertilizers is the oxidation of ammonia (NH3) to nitric oxide (NO). In this reaction, Pt/Rh (95/5 wt. %) is used as a catalyst and a significant Pt-loss occurs due to the high temperature and aggressive chemical conditions. The Pt-loss is unavoidable without compromising the catalytic selectivity. Mitigation of the Pt-loss is performed by Pt-catchment, utilizing a Pd/Ni (95/5 wt. %) net placed downstream of the Pt/Rh catalyst, catching the evaporated Pt. A re-alloying process of Pd/Ni with Pt occurs during Pt-catchment, causing the Pd/Ni wires to swell and the net to grow into something more similar to a porous plate. Alloying Pd with Au reduces the swelling, and the nets keep their shape during operation, only at the cost of a small reduction in Pt-catchment.
For the future of industrial chemistry, oxide materials are seen as a cheaper and more environmentally friendly alternative to noble metals. In this mind-set, selected Pt- and Rh-containing perovskite oxides were synthesized for fundamental studies. The stability of the perovskite structure depend strongly on the oxidation states for the present elements and their size, allowing only certain compositions with Pt- and Rh- to synthesized. | en_US |
| dc.language.iso | en | en_US |
| dc.relation.haspart | Paper I: Grain Reconstruction of Palladium and Palladium-Nickel Alloys for Platinum Catchment. A. S. Fjellvåg, D. Waller, J. Skjelstad and A. O. Sjåstad. Johnson Matthey Technology Review, 2019, 63, (4), 236. DOI: 10.1595/205651319X15597236291099. The article is included in the thesis. Also available at: https://doi.org/10.1595/205651319X15597236291099 | |
| dc.relation.haspart | Paper II: Mechanism of grain reconstruction of Pd and Pd/Ni wires during Pt–catchment. A. S. Fjellvåg, P. S. Jørgensen, D. Waller, D. S. Wragg, M. D. Michiel and A. O. Sjåstad. Materialia, 2022, 21, 101359. DOI: 10.1016/j.mtla.2022.101359. The article is included in the thesis. Also available at: https://doi.org/10.1016/j.mtla.2022.101359 | |
| dc.relation.haspart | Paper III: Platinum catchment using Pd/Au alloys: Effect of enhanced diffusion. A. S. Fjellvåg, D. Waller, T. By and A. O. Sjåstad. Submitted to Industrial & Engineering Chemistry Research. To be published. The paper is not available in DUO awaiting publishing. | |
| dc.relation.haspart | Paper IV: Structural disorder and antiferromagnetism in LaNi1-xPtxO3. A. S. Fjellvåg, Ø. S. Fjellvåg, Y. Breard and A. O. Sjåstad. Journal of Solid State Chemistry, 2021, 299, 122181. DOI: 10.1016/j.jssc.2021.122181. The article is included in the thesis. Also available at: https://doi.org/10.1016/j.jssc.2021.122181 | |
| dc.relation.haspart | Paper V: Interplay of valence states and magnetic interactions in the perovskite system LaNi1–xRhxO3. A. S. Fjellvåg, Ø. S. Fjellvåg, S. Kumar, A. Ruud and A. O. Sjåstad. Journal of Solid State Chemistry, 2021, 298, 122124. DOI: 10.1016/j.jssc.2021.122124. The article is included in the thesis. Also available at: https://doi.org/10.1016/j.jssc.2021.122124 | |
| dc.relation.uri | https://doi.org/10.1595/205651319X15597236291099 | |
| dc.relation.uri | https://doi.org/10.1016/j.mtla.2022.101359 | |
| dc.relation.uri | https://doi.org/10.1016/j.jssc.2021.122181 | |
| dc.relation.uri | https://doi.org/10.1016/j.jssc.2021.122124 | |
| dc.title | Platinum Catchment by Noble Metal Alloys and structural studies of Pt- and Rh-containing perovskites | en_US |
| dc.type | Doctoral thesis | en_US |
| dc.creator.author | Fjellvåg, Asbjørn Slagtern | |
| dc.type.document | Doktoravhandling | en_US |