Restructuring of Palladium Nanoparticles during Oxidation by Molecular Oxygen.

Autor: Usoltsev O; ALBA Synchrotron, Cerdanyola del Valles, Barcelona, 08290, Spain., Stoian D; The Swiss-Norwegian Beamlines (SNBL) at ESRF, BP 220, Grenoble, 38043, France., Skorynina A; ALBA Synchrotron, Cerdanyola del Valles, Barcelona, 08290, Spain., Kozyr E; Department of Chemistry, INSTM and NIS Centre, University of Torino, via Quarello 15A, Turin, 10125, Italy., Njoroge PN; Department of Chemistry, University of Oslo, Sem Saelandsvei 26, Oslo, 0315, Norway., Pellegrini R; Chimet S.p.A. - Catalyst Division, Via di Pescaiola 74, Viciomaggio Arezzo, 52041, Italy., Groppo E; Department of Chemistry, INSTM and NIS Centre, University of Torino, via Quarello 15A, Turin, 10125, Italy., van Bokhoven JA; Paul Scherrer Institute, Villigen, 5232, Switzerland.; Institute for Chemical and Bioengineering, ETH Zurich, Vladimir-Prelog-Weg 1, Zurich, 8093, Switzerland., Bugaev A; Paul Scherrer Institute, Villigen, 5232, Switzerland.
Jazyk: angličtina
Zdroj: Small (Weinheim an der Bergstrasse, Germany) [Small] 2024 Jun 17, pp. e2401184. Date of Electronic Publication: 2024 Jun 17.
DOI: 10.1002/smll.202401184
Abstrakt: An interplay between Pd and PdO and their spatial distribution inside the particles are relevant for numerous catalytic reactions. Using in situ time-resolved X-ray absorption spectroscopy (XAS) supported by theoretical simulations, a mechanistic picture of the structural evolution of 2.3 nm palladium nanoparticles upon their exposure to molecular oxygen is provided. XAS analysis revealed the restructuring of the fcc-like palladium surface into the 4-coordinated structure of palladium oxide upon absorption of oxygen from the gas phase and formation of core@shell Pd@PdO structures. The reconstruction starts from the low-coordinated sites at the edges of palladium nanoparticles. Formation of the PdO shell does not affect the average Pd‒Pd coordination numbers, since the decrease of the size of the metallic core is compensated by a more spherical shape of the oxidized nanoparticles due to a weaker interaction with the support. The metallic core is preserved below 200 °C even after continuous exposure to oxygen, with its size decreasing insignificantly upon increasing the temperature, while above 200 °C, bulk oxidation proceeds. The Pd‒Pd distances in the metallic phase progressively decrease upon increasing the fraction of the Pd oxide due to the alignment of the cell parameters of the two phases.
(© 2024 The Author(s). Small published by Wiley‐VCH GmbH.)
Databáze: MEDLINE
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