The reactivity of different gold‐based catalysts has been examined and re‐discussed on the basis of the most recent literature data, mainly looking at the characterization data obtained by FTIR spectroscopy and HRTEM microscopy. In particular, the CO oxidation reactions at 90 K and at room temperature have been discussed. By comparing samples with different gold particle sizes and different supports it has been deduced that the sites responsible for the adsorption and the reactive activation of CO and O2 are the gold edge sites, in proximity to the support oxygen‐vacancy defects. These defects may produce electron‐rich gold atoms, which may be relevant for oxygen activation and dissociation. As for the water–gas shift reaction, an important role of support sites at the borderline with the gold sites, where water and CO in mutual interaction may be activated, has been proposed. Moreover, a role of oxygen adsorbed on gold particles near oxygen vacancies of the support in the oxidative dehydrogenation of methanol and in the furfural oxidative esterification has been discussed. All the above summarized points confirm the importance of the dual perimeter sites in the catalytic activity of gold catalysts.
Insights into the Reactivity of Gold: an Analysis of FTIR and HRTEM Studies
BOCCUZZI, Flora;MANZOLI, Maela;CHIORINO, Anna;VINDIGNI, FLORIANA
2013-01-01
Abstract
The reactivity of different gold‐based catalysts has been examined and re‐discussed on the basis of the most recent literature data, mainly looking at the characterization data obtained by FTIR spectroscopy and HRTEM microscopy. In particular, the CO oxidation reactions at 90 K and at room temperature have been discussed. By comparing samples with different gold particle sizes and different supports it has been deduced that the sites responsible for the adsorption and the reactive activation of CO and O2 are the gold edge sites, in proximity to the support oxygen‐vacancy defects. These defects may produce electron‐rich gold atoms, which may be relevant for oxygen activation and dissociation. As for the water–gas shift reaction, an important role of support sites at the borderline with the gold sites, where water and CO in mutual interaction may be activated, has been proposed. Moreover, a role of oxygen adsorbed on gold particles near oxygen vacancies of the support in the oxidative dehydrogenation of methanol and in the furfural oxidative esterification has been discussed. All the above summarized points confirm the importance of the dual perimeter sites in the catalytic activity of gold catalysts.File | Dimensione | Formato | |
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