Oxidative Thermal Sintering and Redispersion of Rh Nanoparticles on Supports with High Oxygen Ion Lability

Research output: Contribution to journalArticle

  • External authors:
  • Grammatiki Goula
  • Georgia Botzolaki
  • Amin Osatiashtiani
  • Georgios Kyriakou
  • Richard M. Lambert
  • Ioannis V. Yentekakis

Abstract

The thermal sintering under oxidative conditions of Rh nanoparticles supported on oxides characterized by very different oxygen storage capacities (OSC) and labilities was studied at 750 and 850 °C. Under sintering conditions, significant particle growth occurred for Rh/γ-Al2O3 (up to 120% at 850 °C). In striking contrast, Rh/ACZ (alumina–ceria–zirconia) and Rh/CZ (ceria–zirconia) exhibited marked resistance to sintering, and even moderate (ca. −10% at 850 °C) to pronounced (ca. −60% at 850 °C) redispersion of the Rh. A model is proposed based on a double-layer description of metal–support interactions assigned to back-spillover of labile oxygen ions onto the Rh particles, accompanied by trapping of atomic Rh by the resulting surface oxygen vacancies. This model accounts for the observed resistance to sintering and actual redispersion of Rh, consistent with both alternative sintering mechanisms, namely Ostwald ripening (OR) or particle migration and coalescence (PMC).

Bibliographical metadata

Original languageEnglish
JournalCatalysts
Volume9
Issue number6
DOIs
Publication statusPublished - 17 Jun 2019