Mechanistic studies for depositing highly dispersed Pt nanoparticles on carbon by use of trimethyl(methylcyclopentadienyl)platinum(IV) reactions with O2 and H2

Alia M. Lubers, Christopher Muhich, Kelly M. Anderson, Alan W. Weimer

Research output: Contribution to journalArticle

12 Scopus citations

Abstract

A fundamental understanding is developed for the chemical reaction mechanism that underlies platinum atomic layer deposition (ALD) on a carbon support, XC72R, for use as a fuel cell catalyst. Specifically, trimethyl(methylcyclopentadienyl)platinum(IV) (MeCpPtMe3) was fed as the 1st reactant for ALD on high surface area particles using a well-instrumented fluidized bed reactor equipped with an in-line mass spectrometer. The precursor’s organic ligands were removed by reaction with the 2nd reactant, either oxygen or hydrogen. These experiments were performed on both unmodified and functionalized XC72R. Carbon modification involved reflux with nitric acid, which oxygenated the XC72R. Platinum weight loading, average particle size, and particle dispersion depended on carbon treatment and on the reactant used for ligand removal (oxygen or hydrogen). Deposited platinum particle sizes ranged from 2.6 to 6.7 nm. Transmission electron microscopy, chemisorption, and diffuse reflectance infrared Fourier transform spectroscopy were used to characterize the Pt deposition and carbon support functionalization. More discrete and non-agglomerated platinum nanoparticles were produced using hydrogen, rather than oxygen, as a reactant and when deposition was conducted on functionalized, rather than unmodified, XC72R carbon. The platinum nanoparticles are stabilized by the underlying oxygen added during substrate functionalization and the avoidance of carbon substrate combustion when using hydrogen, instead of oxygen, as the 2nd reactant to remove residual ligands.

Original languageEnglish (US)
JournalJournal of Nanoparticle Research
Volume17
Issue number4
DOIs
StatePublished - Apr 1 2015
Externally publishedYes

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Keywords

  • Atomic layer deposition (ALD)
  • Combustion
  • Fuel cell catalyst
  • Hydrogenation
  • Nitric acid functionalization

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics
  • Modeling and Simulation
  • Chemistry(all)
  • Materials Science(all)
  • Bioengineering

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