Precise Control of Pt Particle Size for Surface Structure-Reaction Activity Relationship

Reem Al-Shareef, Moussab Harb*, Youssef Saih, Samy Ould-Chikh, Dalaver H. Anjum, Jean Pierre Candy, Jean Marie Basset

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

8 Scopus citations

Abstract

The use of surface organometallic chemistry on metal (SOMC/M) allows the controlled and stepwise variation of the platinum particle size in Pt/SiO2 catalysts. This SOMC/M method is possible thanks to the better affinity of most organometallic compounds with the surface of zerovalent metal particles covered with hydrogen than their support. In this paper, Pt(acac)2 was used as the organometallic precursor, silica as a support, and then hydrogen to reduce the adsorbed organometallic layer on top of the starting Pt nanoparticle. We partially succeeded in adding one Pt layer with a stepwise particle size increase of around 0.6 nm when going from the first (1G) to the second (2G) refilling run, as obtained from TEM and H2 chemisorption analysis and then confirmed by DFT calculations. The metal loading could be kept at a very low level (<1-2 wt %), which is relevant for catalytic applications. The particle size distribution remained relatively narrow even after two refilling runs, allowing more precise relationships between particle size and catalytic properties to be established. The TORH (for hydrogenolysis) dramatically decreased, while TORI (for skeletal isomerization) slightly increased with increasing the particles size. It is therefore suggested that hydrogenolysis might preferentially occur on low coordination surface platinum atoms (corners and edges), while isomerization occurs mostly on the facets.

Original languageEnglish (US)
Pages (from-to)23451-23459
Number of pages9
JournalJOURNAL OF PHYSICAL CHEMISTRY C
Volume122
Issue number41
DOIs
StatePublished - Oct 18 2018

Bibliographical note

Publisher Copyright:
© 2018 American Chemical Society.

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • General Energy
  • Surfaces, Coatings and Films
  • Physical and Theoretical Chemistry

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