Structure, stability, and electronic interactions of polyoxometalates on functionalized graphene sheets

Langmuir. 2013 Jan 8;29(1):393-402. doi: 10.1021/la303408j. Epub 2012 Dec 24.

Abstract

Polyoxometalates (H(3)PMo(12)O(40), H(3)PW(12)O(40), H(4)PMo(11)VO(40)) supported on oxygen- and alkyl-functionalized graphene sheets were investigated. Discrete molecular species were directly observed by electron microscopy at loadings below 20 wt.%. The interaction between the polyoxometalates and the graphene surface was found to significantly impact their vibrational spectra and a linear correlation between the frequency of the M-O(c)-M vibration and the dispersion was evidenced by FTIR. While bulk-like electronic properties were observed for small aggregates (2-5 nm), UV-vis spectroscopy and cyclic voltammetry revealed changes in the electronic structure of isolated molecular species as a result of their interaction with graphene. Because of the ability to disperse alkyl-functionalized graphene in a variety of polar and nonpolar solvents, the materials synthesized in this work provide an opportunity to disperse polyoxometalates in media in which they would not dissolve if unsupported.

Publication types

  • Research Support, American Recovery and Reinvestment Act
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Drug Stability
  • Electrons*
  • Graphite / chemistry*
  • Hydrophobic and Hydrophilic Interactions
  • Microscopy, Electron, Scanning
  • Oxidation-Reduction
  • Oxygen / chemistry*
  • Spectroscopy, Fourier Transform Infrared
  • Surface Properties
  • Tungsten Compounds / chemistry*

Substances

  • Tungsten Compounds
  • polyoxometalate I
  • Graphite
  • Oxygen