Gold, cluster catalyst

Fig. 9 Dependence of catalytic activity of MgO-supported catalysts containing cationic gold and (except in the most active catalyst) gold clusters for ethene hydrogenation at 760 Torr and 353 K (reactive mixture of He, ethene, and H2—ethene partial pressure, r ethene. 40 Torr Phydrogen. 160 Torr the balance He). Note the nonlinearity of the scale at the top [53]...

Gold clusters supported on a mixed Ti02-Si02 surface show activity for propylene epoxidation comparable to Ti02-supported Au catalysts but with enhanced stability.104 Therefore, it was decided... 

The oxidation of CO is the simplest reaction and has been the most intensively studied since Langmuir first presented a theory of adsorption and catalysis for this reaction [13]. Supported Au NPs such as Au/Ti02, Au/Fe203 and Au/Co304 are extraordinarily active in CO oxidation, even at 200 K, and are much more active than the other noble metals catalysts at temperatures below 400 K [14—16]. Gold clusters composed of several atoms can promote the reaction between CO and 02 to form C02 at as low as 40 K [17]. Most recently, Lahr and Ceyer [18] have extended the temperature range at which the activity for CO oxidation is observed to as low as 70 K by using an Au/Ni surface alloy. 

Heteronuclear gold cluster compounds have, therefore, been proposed as potential precursors for the synthesis of selective catalysts and also as models of the modifications to the substrate that arise at a molecular level. Braunstein has reviewed in more detail the catalytic applications of gold-containing polymetallic systems (212). 

Since Haruta s initial report (Sanchez et al., 1997) of the unexpected activity of supported gold catalysts for low-temperature CO oxidation, there has been a resurgence of research and interest in gold-mediated catalysis. Supported gold clusters have since been found to be active in a... 

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