title: Comparison of the Activity and the Stability in CO Oxidation of Au-Cu Catalysts Supported on TiO2 in Anatase or Rutile Phase.
abstract: Au-Cu catalysts supported on anatase or rutile phases were prepared by deposition-precipitation method. The titania polymorph used as the support determined the catalytic behavior. For the Au-Cu/rutile catalysts, the metallic phase had smaller dimensions than for the Au-Cu/anatase catalysts. The catalysts supported on anatase, however, were more active and stable than those supported on rutile. A systematic study of the catalytic activity for CO oxidation as a function of the temperature of activation and the aging time was performed. The catalytic properties were correlated with the properties of the catalysts analyzed with X-ray powder diffraction, refinement of the crystalline structures with the Rietveld method, and transmission electron microscopy. When the support was anatase, a pretreatment at 400 degrees C in air led to the most active catalysts, whereas when the support was rutile, a pretreatment between 200 and 300 degrees C in air led to the most active catalysts; activation under hydrogen generated less active catalysts. The Au-Cu catalysts activated in air were more active for the oxidation of CO than the respective monometallic gold catalysts, indicating a promoting effect between gold and copper to catalyze this reaction.
authors.forename: Rodolfo
authors.initials: R
authors.lastname: Zanella
authors.forename: Xim
authors.initials: X
authors.lastname: Bokhimi
authors.forename: Viridiana
authors.initials: V
authors.lastname: Maturano
authors.forename: Antonio
authors.initials: A
authors.lastname: Morales