Supported Gold in CO Oxidation, the

SUPPORTED GOLD IN CO OXIDATION, THE WATER-GAS SHIFT, AND DeSOx REACTIONS 

Chemistry Department, Brookhaven National Laboratory, Upton, NY 11973, USA 

Gold particles supported on titania are active catalysts for the low temperature oxidation of CO. This phenomenon was originally discovered by Haruta and coworkers in the early 1990s, and has been corroborated by many subsequent studies. - - - - The exact catalytic activity of the Au/TiOj system depends on the method of preparation and the dispersion of the metal on the support, but in general Au particles with sizes between 2 and 4 nm display a catalytic activity for CO oxidation much larger than that of bulk metallic gold. New preparation methods aim for the synthesis of very small Au particles ( 2 nm) with an extremely high catalytic activity.  

The Au/Ti02 systems lose catalytic activity over time as a consequence of the sintering of the Au particles. The smaller the initial size of the particles, the more dramatic the negative effects of sintering. In the case of Au nanoparticles dispersed on TiC, the interactions of the admetal with the carbide substrate are stronger than typical interactions with oxides, and the Au/TiC system is an excellent catalyst for CO oxidation. - -  

Au particles supported on reducible oxides such as titania or ceria are also efficient catalysts for the water-gas shift, the destruction of sulfur dioxide (DeSOx processes), the complete oxidation of methane, the selective or partial oxidation of propene, the hydrogenation of CO and olefins, and the reduction of NO with hydrocarbons. Depending on the conditions, Au/TiOs 

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