155 Catalytic Activity of Pd-Au Core-Shell Nanoparticles for Volatile Organic Compounds Oxidation

Thursday, November 5, 2009
Ballroom A+B (Camino Real Hotel)
M. Hosseini , Laboratoire de Catalyse et Environnement, University of Littoral Côte d'Opale, Dunkerque, France
S. Siffert , Laboratoire de Catalyse et Environnement, University of Littoral Côte d'Opale, Dunkerque, France
A. Aboukaïs , Laboratoire de Catalyse et Environnement, University of Littoral Côte d'Opale, Dunkerque, France
G. B. Saupe , Department of Chemistry, University of Texas at El Paso, El Paso, TX
M. Zarei , Department of Chemistry, University of Texas at El Paso, El Paso, TX
S. Masud , Department of Chemistry, University of Texas at El Paso, El Paso, TX
B. L. Su , Laboratoire de Chimie des Matériaux Inorganiques (CMI), University of Namur (FUNDP), Namur, Belgium
Volatile Organic compounds (VOCs) are recognized as major contributors to air pollution, either directly through their toxic nature, or indirectly as ozone and smog precursors. Catalytic combustion is one of the most important processes for VOC destruction at low concentrations. Noble metal exhibits low light-off temperature in the oxidation of hydrocarbons. Palladium is extensively used as the active and selective component in complete oxidation of VOC. Modification of palladium with gold often results in improvement in the catalytic activity for oxidation. The addition of a second metal can favor the reduction of the first, increase the dispersion of a metal, or decrease its fritting. The activity and selectivity of supports for Pd and Au catalysts in total oxidation has been reported to depend on the type of metal oxide support.

In our work, titania supported bimetallic Pd-Au and Au–Pd catalysts with the core–shell structure were prepared by chemical deposition of Pd over Au seeds and Au over Pd respectively.

Temperature Programmed Reduction and UV–vis spectrophotometry were used to characterize the core–shell and monometallic samples.

The catalytic tests showed that the Pd(shell)-Au(core)/TiO2 could significantly improve the catalytic activity in the low temperature oxidation of toluene and propene.

The highest activity of PdAu/TiO2 can be related to the presence of a synergetic effect between palladium shell and gold core. Study of the catalytic performance with “Operando’’ DRIFT allowed following the VOCs oxidation but also suggests an interaction between the adsorbed molecule and the catalyst, which decreases when the activity for oxidation reaction increases.

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