In situ formation of cobalt nanoclusters in sol-gel silica films for single-walled carbon nanotube growth

Li Wei, Bo Wang, Dapeng Liu, Lain-Jong Li, Yanhui Yang, Yuan Chen*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

A facile method was developed for in situ formation of Co nanoclusters in sol-gel silica thin films spin-coated on Si wafers. The size and density of Co nanoclusters can be controlled by spin-coating speeds, annealing methods, reduction temperatures under H2, and metal precursor concentrations in tetraethylorthosilicate solutions. The optimized preparation condition, spin-coating speed of 9000 rpm, annealing at 500°C in air followed by reduction at 800°C in H2, resulted in silica films as thin as 60 nm and Co nanoclusters with a mean diameter of 1.5 nm. Morphological and chemical characteristics of thin films and nanoclusters were studied by atomic force microscopy and X-ray photoelectron spectroscopy, respectively. Subsequently, these Co nanoclusters were successfully used to grow SWCNTs by CO decomposition. Film containing Co monometallic clusters produced SWCNTs of 1.3 nm in diameter, whereas film having Co/Mo bimetallic clusters produced SWCNTs of 0.9 nm. This sol-gel approach allowed not only easy catalyst patterning on a thin film but also a fine-tuning of SWCNT properties, e.g., diameter.

Original languageEnglish (US)
Pages (from-to)99-106
Number of pages8
JournalNano
Volume4
Issue number2
DOIs
StatePublished - Aug 12 2009

Keywords

  • Co nanocluster
  • Single-walled carbon nanotube
  • Sol-gel
  • Thin film

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics

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