Hydrothermal growth of mesoporous SBA-15 silica in the presence of PVP-stabilized Pt nanoparticles: Synthesis, characterization, and catalytic properties

Hyunjoon Song, Robert Martin Rioux, Jr., James D. Hoefelmeyer, Russell Komor, Krisztian Niesz, Michael Grass, Peidong Yang, Gabor A. Somorjai

Research output: Contribution to journalArticle

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Abstract

A novel high surface area heterogeneous catalyst based on solution phase colloidal nanoparticle chemistry has been developed. Monodisperse platinum nanoparticles of 1.7-7.1 nm have been synthesized by alcohol reduction methods and incorporated into mesoporous SBA-15 silica during hydrothermal synthesis. Characterization of the Pt/SBA-15 catalysts suggests that Pt particles are located within the surfactant micelles during silica formation leading to their dispersion throughout the silica structure. After removal of the templating polymer from the nanoparticle surface, Pt particle sizes were determined from monolayer gas adsorption measurements. Infrared studies of CO adsorption revealed that CO exclusively adsorbs to atop sites and red-shifts as the particle size decreases suggesting surface roughness increases with decreasing particle size. Ethylene hydrogenation rates were invariant with particle size and consistent with a clean Pt surface. Ethane hydrogenolysis displayed significant structure sensitivity over the size range of 1-7 nm, while the apparent activation energy increased linearly up to a Pt particle size of ∼4 nm and then remained constant. The observed rate dependence with particle size is attributed to a higher reactivity of coordinatively unsaturated surface atoms in small particles compared to low-index surface atoms prevalent in large particles. The most reactive of these unsaturated surface atoms are responsible for ethane decomposition to surface carbon. The ability to design catalytic structures with tunable properties by rational synthetic methods is a major advance in the field of catalyst synthesis and for the development of accurate structure-function relationshios in heteroaeneous reaction kinetics.

Original languageEnglish (US)
Pages (from-to)3027-3037
Number of pages11
JournalJournal of the American Chemical Society
Volume128
Issue number9
DOIs
StatePublished - Mar 8 2006

Fingerprint

Particle Size
Silicon Dioxide
Nanoparticles
Silica
Particle size
Growth
Ethane
Carbon Monoxide
Adsorption
Atoms
Catalysts
Hydrogenation
Micelles
Gas adsorption
Hydrogenolysis
Platinum
Surface-Active Agents
Hydrothermal synthesis
SBA-15
Reaction kinetics

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

Cite this

Song, Hyunjoon ; Rioux, Jr., Robert Martin ; Hoefelmeyer, James D. ; Komor, Russell ; Niesz, Krisztian ; Grass, Michael ; Yang, Peidong ; Somorjai, Gabor A. / Hydrothermal growth of mesoporous SBA-15 silica in the presence of PVP-stabilized Pt nanoparticles : Synthesis, characterization, and catalytic properties. In: Journal of the American Chemical Society. 2006 ; Vol. 128, No. 9. pp. 3027-3037.
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Hydrothermal growth of mesoporous SBA-15 silica in the presence of PVP-stabilized Pt nanoparticles : Synthesis, characterization, and catalytic properties. / Song, Hyunjoon; Rioux, Jr., Robert Martin; Hoefelmeyer, James D.; Komor, Russell; Niesz, Krisztian; Grass, Michael; Yang, Peidong; Somorjai, Gabor A.

In: Journal of the American Chemical Society, Vol. 128, No. 9, 08.03.2006, p. 3027-3037.

Research output: Contribution to journalArticle

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T1 - Hydrothermal growth of mesoporous SBA-15 silica in the presence of PVP-stabilized Pt nanoparticles

T2 - Synthesis, characterization, and catalytic properties

AU - Song, Hyunjoon

AU - Rioux, Jr., Robert Martin

AU - Hoefelmeyer, James D.

AU - Komor, Russell

AU - Niesz, Krisztian

AU - Grass, Michael

AU - Yang, Peidong

AU - Somorjai, Gabor A.

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