Rapid Sintering in NO of Nanometer-Sized Pt Particles on γ-Al2O3 Observed by CO Temperature-Programmed Desorption and Transmission Electron Microscopy

Ostwald Ripening of Platinum Nanoparticles Confined in a Carbon Nanotube/Silica‐Templated Cylindrical Space

“…TEM images and resulting average size distributions, indicating that smaller NPs have eventually disappeared and larger ones have been obtained, are consistent with a sintering process of Pt NPs governed by an Ostwald ripening mechanism. The corresponding mass-transport can be justified if mediated by Pt atoms, or more likely by Ptoxygen species (the sintering rate of Pt NPs in oxidative environments was reported to be accelerated due to the formation of volatile Pt-oxygen species) [21]. Besides the oxygen-rich environment, we have to take into account the increased temperatures reached and the fact that Pt NPs are neither free nor supported on planar substrates but confined in the cylindrical empty spaces given once the carbonization of CNTs and the compaction of silica are accomplished.…”

Study on the hydrothermal and SO2 stability of Al2O3-supported manganese and iron oxide catalysts for lean CO oxidation

“…The deactivating SO x species can partially be removed by thermal treatment, whereas the efficiency is enhanced under rich conditions [16,19]. Furthermore, high temperatures (>600 • C) can cause irreversible degradation of the catalysts implying sintering as well as phase transformation and crystallization of substrate and precious metal particles [18,[20][21][22][23][24]. Thus, the thermal aging of automotive catalysts is currently inhibited by using sintering barriers such as La 2 O 3 , ZrO 2 and CeO 2 [25,26].…”

Bridging nanoscience and surface science to understand heterogeneous catalysis

“…If this initial model was only supported by experimental data on Pt 29,30 and Ru, 31 a second set of publications is in line with this relationship. More precisely, experiments performed on the following nanomaterials: Rh/SiO 2 , 32 Rh/γ-Al 2 O 3 , 33 Ir/H-ZSM-5 34 as well as Cu/Al 2 O 3 , 35 Pt/SiO 2 36 are coherent with this simple model.…”