Restructuring of Palladium Nanoparticles during Oxidation by Molecular Oxygen.
Small
; : e2401184, 2024 Jun 17.
Article
in En
| MEDLINE
| ID: mdl-38884188
ABSTRACT
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 PdâPd 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 PdâPd 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.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Language:
En
Journal:
Small
Journal subject:
ENGENHARIA BIOMEDICA
Year:
2024
Type:
Article
Affiliation country:
Spain