Gold particle size effects in the gas-phase hydrogenation of m-dinitrobenzene over Au/TiO2

Fernando Cardenas-Lizana, Santiago Gomez-Quero, Hicham Idriss, Mark A. Keane

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The effect of Au particle size, supported on TiO2, on the gas-phase hydrogenation of m-dinitrobenzene has been considered. The catalysts (Au loading = 0.1 and 1 mol%) were prepared by impregnation with HAuCl4 and a range of Au particle sizes (3.4-10.0 nm) was generated by temperature-programmed reduction over the interval 603 K <= T <= 1273 K. A thermal treatment of TiO2 at T >= 873 K was required for the allotropic change from anatase to rutile but the presence of Au lowered the requisite temperature for complete transformation by up to 400 K. m-Dinitrobenzene hydrogenation exhibited a particle size sensitivity where higher specific rates were obtained with smaller Au particles, irrespective of the support composition (i.e. anatase:rutile ratio). The reaction over each Au/TiO2 catalyst generated m-phenylenediamine (reduction of both -NO2 groups) and/or m-nitroaniline (reduction of one -NO2 group). A parallel/consecutive kinetic model has been applied to quantify the catalytic selectivity where Au particles <5 nm favoured m-nitroaniline production. The dependence of hydrogenation performance on Au particle size is accounted for in terms of a modification to Au electronic character, which impacts on m-dinitrobenzene adsorption/activation. (c) 2009 Elsevier Inc. All rights reserved.

Original languageEnglish
Pages (from-to)223-234
Number of pages12
JournalJournal of Catalysis
Issue number2
Early online date28 Oct 2009
Publication statusPublished - 10 Dec 2009

Bibliographical note

We are grateful to Dr. W. Zhou and Mr. R. Blackley for their contribution to the TEM analysis. We acknowledge Dr. P. Vaqueiro and M. L. Romero for assistance with the DRS UV–vis measurements. This work was financially supported by EPSRC through Grant 0231 110525. EPSRC support for free access to the TEM/SEM facility at the University of St Andrews is also acknowledged.


  • Au particle size
  • Au/TiO2
  • anatase
  • rutile
  • m-dinitrobenzene hydrogenation
  • metal-support interaction
  • non-stoichiometric oxides
  • aromatic nitro-compounds
  • catalytic-hydrogenation
  • selective hydrogenation
  • titanium-dioxide
  • chemoselective hydrogenation
  • CO oxidation
  • crotonaldehyde hydrogenation
  • nitrobenzene hydrogenation


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