Catalysis Letters, Vol.148, No.1, 267-276, 2018
Gold Promotion of MCM-41 Supported Ruthenium Catalysts for Selective Hydrogenation of alpha,beta-Unsaturated Aldehydes and Ketones
In the challenging alpha,beta-unsaturated aldehydes and ketones hydrogenation to unsaturated alcohols (UA), Ru-Au/MCM-41 exhibits superior high activity and selectivity compared with monometallic Ru. TEM and XRD measurements were applied to characterize as-prepared Ru/MCM-41 and Ru-Au/MCM-41 catalysts. The results indicated that the addition of Au significantly improved the dispersion of the metallic Ru components, thus enhancing the activity of the catalyst. The enhancement of selectivity to UA could be attributed to the interaction of Ru and Au components in the support and the morphology effect of Ru, which are revealed by in-suit DRIFTS, H-2-TPD, XPS, and FTIR measurements. The morphological and electronic aspects of Ru particles lead to a favorable adsorption of C=O bond versus C=C bond. A dramatic increase in activity and selectivity of the reactions were observed upon the addition of Au, suggesting that the significant synergistic effects between Ru and Au play an important role in the activity and selectivity of the reaction. It is the first time that chemoselective hydrogenation of alpha,beta-unsaturated aldehydes and ketones were studied on Ru-Au/MCM-41 catalysts.