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A series of Au/ZrO 2 catalysts with low content of gold (<1 wt.%) were prepared by deposition-precipitation method and evaluated in the low-temperature water-gas shift reaction (WGSR) under H 2-rich reformate atmosphere. The effect of pre-calcination temperature of ZrO 2 on the structural and surface properties of the freshly reduced Au/ZrO 2 catalysts was investigated by XRD, N 2- physisorption, HRTEM, UV-Vis DRS, AAS, EPR and XPS characterizations. The catalytic evaluation results reveal that the one supported on ZrO 2 calcined at 350°C shows the best catalytic performance. Correlating to the characterization results, it is found that the catalytic performance of Au/ZrO 2 catalysts strongly depends on the concentration of F-center defects on ZrO 2 surface. EPR and XPS results disclose that electrons can be transferred from F-center to the supported Au, resulting in the formation of activated electron-rich Au cluster, which is responsible for the high catalytic activity of the Au/ZrO 2 catalysts. Moreover, the electron transfer leads to the firm anchoring of Au cluster by the F-center, thus favoring a high catalytic stability. It is proposed that the active site for WGSR on the Au/ZrO 2 catalysts can be expressed as Au δ-[V o -]Zr 3+, where [V o -] represents an F-center. © 2012 Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.
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International Journal of Hydrogen Energy
ISSN: 0360-3199
Year: 2012
Issue: 17
Volume: 37
Page: 12292-12300
3 . 5 4 8
JCR@2012
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JCR@2023
JCR Journal Grade:1
CAS Journal Grade:1
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