In situ study of the thermal stability of supported Pt nanoparticles and their stabilization via atomic layer deposition overcoating
| Autor: | Ji-Yu Feng, Michiel Van Daele, Thomas Dobbelaere, Kevin Van de Kerckhove, Christophe Detavernier, Matthias Minjauw, Philipp Brüner, Jolien Dendooven, Alessandro Coati, Daniel Hermida-Merino, Ranjith Karuparambil Ramachandran, Eduardo Solano |
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| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
PLATINUM
Materials science Scattering CATALYSTS 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology OXIDATION 01 natural sciences 0104 chemical sciences Atomic layer deposition Chemistry Chemical engineering Low-energy ion scattering Physics and Astronomy Grazing-incidence small-angle scattering Particle General Materials Science Thermal stability HYDROGENATION Particle size 0210 nano-technology Layer (electronics) |
| Zdroj: | NANOSCALE |
| ISSN: | 2040-3364 2040-3372 |
| Popis: | Downscaling of supported Pt structures to the nanoscale is motivated by the augmentation of the catalytic activity and selectivity, which depend on the particle size, shape and coverage. Harsh thermal and chemical conditions generally required for catalytic applications entail an undesirable particle coarsening, and consequently limit the catalyst lifetime. Herein we report an in situ synchrotron study on the stability of supported Pt nanoparticles and their stabilization using atomic layer deposition (ALD) as the stabilizing methodology against particle coarsening. Pt nanoparticles were thermally annealed up to 850 degrees C in an oxidizing environment while recording in situ synchrotron grazing incidence small angle X-ray scattering (GISAXS) 2D patterns, thereby obtaining continuous information about the particle radius evolution. Al2O3 overcoat as a protective capping layer against coarsening via ALD was investigated. In situ data proved that only 1 cycle of Al2O3 ALD caused an augmentation of the onset temperature for particle coarsening. Moreover, the results showed a dependence of the required overcoat thickness on the initial particle size and distribution, being more efficient (i.e. requiring lower thicknesses) when isolated particles are present on the sample surface. The Pt surface accessibility, which is decisive in catalytic applications, was analyzed using the low energy ion scattering (LEIS) technique, revealing a larger Pt surface accessibility for a sample with Al2O3 overcoat than for a sample without a protective layer after a long-term isothermal annealing. |
| Databáze: | OpenAIRE |
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