Restructuring of supported Pd by green solvents: an operando quick EXAFS (QEXAFS) study and implications for the derivation of structure–function relationships in Pd catalysis
| Autor: | Christopher J. Mulligan, John B. Brazier, Luis A. Adrio, Hermann Emerich, King Kuok (Mimi) Hii, Klaus Hellgardt, Elena M. Barreiro, Mark A. Newton |
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| Přispěvatelé: | Engineering & Physical Science Research Council (EPSRC), Engineering & Physical Science Research Council (E |
| Rok vydání: | 2016 |
| Předmět: |
inorganic chemicals
Nanoparticle chemistry.chemical_element OXIDATION 010402 general chemistry 01 natural sciences Catalysis SELECTION GUIDES NANOPARTICLES Organic chemistry Science & Technology Aqueous solution Extended X-ray absorption fine structure Chemistry Physical PALLADIUM 010405 organic chemistry Chemistry ALCOHOLS HYDROGEN ETHYLENE 0104 chemical sciences Solvent Chemical engineering Transmission electron microscopy X-RAY-ABSORPTION Physical Sciences CLUSTERS Dispersion (chemistry) LIGAND-FREE Palladium |
| Zdroj: | 'Catalysis Science & Technology ', vol: 6, pages: 8525-8531 (2016) |
| ISSN: | 2044-4761 2044-4753 |
| DOI: | 10.1039/c6cy02073a |
| Popis: | Transmission electron microscopy (TEM) is commonly used as an ex-situ technique to determine structural changes by comparing images of catalyst particles before and after a reaction. This requires the use of an alcoholic solvent to disperse the particles on a grid. In this work, we will show that Pd catalysts can be transformed during the procedure, by using EXAFS to determine the structure of Pd catalysts in different environments (as dry or wet samples). Supported palladium nanoparticles exposed to aqueous ethanolic solution (50% w/v) are transformed to a common, reduced, and hydrogen-contaminated state, irrespective of their initial habit or support. Catalysts comprised of nanosize PdO are reduced at ca. 350 K, whereas samples comprised of very small (ca. ≤ 10 atoms) Pd particles react with the solvent at just above room temperature and agglomerating with considerable loss of dispersion. As such any potential benefits to catalysis sought through the synthesis of very highly dispersed metallic Pd supported upon a range of inorganic dispersants will be rapidly erased through the action of such solvents. |
| Databáze: | OpenAIRE |
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