Promotion of Au(en)2Cl3-Derived Au/Fumed SiO2 by Treatment with KMnO4

Hongfeng Yin, Zhen Ma, Steven H. Overbury and Sheng Dai*
Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
J. Phys. Chem. C, 2008, 112 (22), pp 8349–8358
DOI: 10.1021/jp800797t
Publication Date (Web): May 8, 2008
Copyright © 2008 American Chemical Society
* Corresponding author. Tel: 1-865-576-7307 . Fax: 1-865-576-5235. E-mail: dais@ornl.gov.

Abstract

A new method for the removal of organic ligands used in the synthesis of nanoparticle catalysts via solution-phase chemical oxidation and subsequent pretreatment at moderate temperatures was developed. This synthesis protocol is advantageous for the preparation of highly dispersed gold catalysts with minimum sintering. Highly active Au/SiO2-based catalysts were prepared by treating Au(en)2Cl3-derived Au/fumed SiO2 in strongly oxidative KMnO4 solutions. The low-temperature activity in CO oxidation increased dramatically following the KMnO4 treatment and subsequent thermal activation (including treatment in O2−He at 300–600 °C). The influences of the pH values of KMnO4 solutions and temperatures of activation in O2−He prior to the reaction testing were investigated, and relevant characterization using XRD, TEM, TG/DTG, SEM, EDX, and ICP-OES was conducted. The catalyst stability in CO oxidation was studied as a function of reaction time on stream. The origin of the promotional effect was discussed.

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History

  • Published In Issue June 05, 2008
  • Article ASAPMay 08, 2008
  • Received: January 27, 2008
    Revised: March 1, 2008

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