Understanding the chemistry during the preparation of Pd/SSZ-13 for the low-temperature NO adsorption: The role of NH4-SSZ-13 support
| Autor: | Johannes W. Schwank, Adarsh Bhat, Yongdan Li, Xiaoyin Chen, Huawang Zhao |
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| Přispěvatelé: | Tianjin University, University of Michigan, Ann Arbor, Industrial chemistry, Department of Chemical and Metallurgical Engineering, Aalto-yliopisto, Aalto University |
| Rok vydání: | 2021 |
| Předmět: |
02 engineering and technology
010402 general chemistry Dispersion (geology) 01 natural sciences Medicinal chemistry chemistry of preparation Catalysis Ion law.invention Metal Adsorption law Oxidizing agent Calcination General Environmental Science NO adsorption Chemistry Process Chemistry and Technology low-temperature storage Pd/SSZ-13 021001 nanoscience & nanotechnology 0104 chemical sciences environmental catalysis SSZ-13 visual_art visual_art.visual_art_medium 0210 nano-technology Brønsted–Lowry acid–base theory |
| Zdroj: | Applied Catalysis B: Environmental. 282:119611 |
| ISSN: | 0926-3373 |
| DOI: | 10.1016/j.apcatb.2020.119611 |
| Popis: | The chemistry during the preparation of Pd/SSZ-13, including impregnation and calcination process, was investigated, using Pd(NO3)2 as precursor and NH4-SSZ-13 as the support. Special attention was paid on analyzing the improvement effect of NH4-SSZ-13 support on Pd2+ ions dispersion. The Pd(NO3)2 precursor remained intact after impregnation and transformed to Pd(NH3)x2+ during calcination at 200−290 °C, and then converted to Pd2+ ions occupying the ion-exchange sites by oxidizing the NH3 ligands to N2 at 290−450 °C. The formation of Pd(NH3)x2+ intermediates is a critical factor for achieving high Pd2+ dispersion, probably due to the fact that NH3 ligands give the intermediates high mobility, facilitating their movement to the ion-exchange sites. The PdO formation might be related to the excessive reduction of Pd2+ sites to metallic Pd, when catalyzing the oxidation of NH3 ligands and the NH4+ on the Brønsted acid sites. |
| Databáze: | OpenAIRE |
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