Carbon support effects on bimetallic Pt-Ru nanoparticles formed from molecular precursors

Journal Article · Tue Feb 02 04:00:00 EST 1999 · Langmuir

DOI:https://doi.org/10.1021/la980921b· OSTI ID:680000

Hills, C W; Nashner, M S; Frenkel, A I; Shapley, J R; Nuzzo, R G ^[1]

---

1. Univ. of Illinois, Urbana, IL (United States)

The authors describe the preparation, structural characterization, and support interactions experienced by two different compositions of Pt-Ru nanoparticles supported on several carbons (carbon black, fullerene soot, and desulfurized carbon black). The bimetallic nanoparticles, obtained by reduction of the neutral molecular precursors PtRu{sub 5}C(CO){sub 16} and Pt{sub 2}Ru{sub 4}(CO){sub 18} (the latter of which lacks a central stabilizing carbide core) at elevated temperatures in a hydrogen atmosphere, show a structural homology, exhibiting exceptionally narrow size and compositional distributions. A detailed structural picture of the nanoparticles has been deduced on the basis of in-situ extended X-ray absorption fine structure (EXAFS), scanning transmission electron microscopy (STEM), energy-dispersive X-ray analysis (EDX), and X-ray absorption near edge structures (XANES). These techniques reveal that the bimetallic nanoparticles have Pt/Ru compositions of 1:5 and 2:4, respectively, and average diameters lying between 1.0 and 1.5 nm. The local metal coordination environments reveal a nonstatistical distribution of the two metals in the nanoparticles. Specifically, Pt shows a marked preference for segregation to the particle surfaces under an H{sub 2} atmosphere. The data also reveal a difference in the structural environment of the nanoparticles when formed on the fullerene soot support. Interactions between Ru and low-Z atoms are revealed through XANES, which, taken collectively with the other data presented, leads the authors to propose a possible Ru-C compound formation on this latter support phase.

• Sponsoring Organization: USDOE, Washington, DC (United States); Defense Advanced Research Projects Agency, Arlington, VA (United States)
• DOE Contract Number: FG02-91ER45439
• OSTI ID: 680000
• Report Number(s): CONF-980314--
• Journal Information: Langmuir, Journal Name: Langmuir Journal Issue: 3 Vol. 15; ISSN LANGD5; ISSN 0743-7463
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
40 CHEMISTRY
CARBON BLACK
CATALYST SUPPORTS
CATALYSTS
CHEMICAL PREPARATION
CONFIGURATION INTERACTION
CRYSTAL STRUCTURE
FULLERENES
PLATINUM
RUTHENIUM