Sn-modification of Pt7/alumina model catalysts: Suppression of carbon deposition and enhanced thermal stability
| Autor: | Bradley J. Allen, Timothy J. Gorey, Borna Zandkarimi, Ashley C. Cass, Guangjing Li, Anastassia N. Alexandrova, Scott L. Anderson |
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| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Ethylene
Materials science physics.chem-ph FOS: Physical sciences General Physics and Astronomy Sintering 010402 general chemistry 01 natural sciences Catalysis chemistry.chemical_compound Electron transfer Atomic layer deposition Engineering Physics - Chemical Physics 0103 physical sciences Deposition (phase transition) Thermal stability Physical and Theoretical Chemistry Chemical Physics (physics.chem-ph) chemistry.chemical_classification Chemical Physics 010304 chemical physics Alkene 0104 chemical sciences chemistry Chemical engineering Physical Sciences Chemical Sciences |
| Zdroj: | The Journal of chemical physics, vol 152, iss 2 |
| Popis: | An atomic layer deposition process is used to modify size-selected Pt7/alumina model catalysts by Sn addition, both before and after Pt7 cluster deposition. Surface science methods are used to probe the effects of Sn-modification on the electronic properties, reactivity, and morphology of the clusters. Sn addition, either before or after cluster deposition, is found to strongly affect the binding properties of a model alkene, ethylene, changing the number and type of binding sites, and suppressing decomposition leading to carbon deposition and poisoning of the catalyst. Density functional theory on a model system, Pt4Sn3/alumina, shows that the Sn and Pt atoms are mixed, forming alloy clusters with substantial electron transfer from Sn to Pt. The presence of Sn also makes all the thermally accessible structures closed shell, such that ethylene binds only by {\pi}-bonding to a single Pt atom. The Sn-modified catalysts are quite stable in repeated ethylene temperature programmed reaction experiments, suggesting that the presence of Sn also reduces the tendency of the sub-nano-clusters to undergo thermal sintering. |
| Databáze: | OpenAIRE |
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