Influence of Calcination Temperature on Properties of Au/Fe2O3 Catalysts for Low Temperature Water Gas Shift Reaction

A series of Au/Fe2O3 catalysts for the water gas shift (WGS) reaction were prepared by modified deposition-precipitation method. The sample calcined at 300 °C showed higher catalytic activity and better stability than other samples. Using N2 physisorption, in situ XRD, H2-TPR, and XPS techniques, the influence of calcination temperature on properties of Au/Fe2O3 catalyst was explored, and the cause of deactivation was analyzed as well. The results showed that the catalytic behaviors were related to the interaction between Au and Fe2O3, and the reductive property of support, both of which were significantly affected by calcination temperature. Furthermore, according to the results of XPS, although stable carbonate and carbonyl surface species were found on the spent catalysts, the semiquantitative analysis of these species indicated that they were not the main cause of the deactivation. In fact, the deactivation of Au/Fe2O3 was sensitive to the structure change of support. During the water gas shift reaction, Fe3O4 particle would aggregate and crystallize leading to increase in the crystallinity of support and a significant reduction in the surface area of the catalysts, which resulted in the deactivation of Au/Fe2O3.