Influence Of Lewis Acid On The Activity And Selectivity Of Pt/Mcm-41 (Al) Catalysts For Oxidation Of C-3 Polyols In Base-Free Medium

The nature of a solid support is crucial for the metal-support interaction, leading to tunable activity and selectivity on supported catalysts. We prepared the Lewis acidic MCM-41 (Al)-supported Pt catalysts for selective oxidation of C-3 polyols in base-free medium. Catalyst characterizations (e.g., high-angle annular dark-field scanning transmission electron microscopy and X-ray photoelectron spectroscopy) and density functional theory calculations confirmed that the electron transfer from Pt to MCM-41 (Al) weakens the adsorption of reactants and products, and the enhanced metal-support interaction between Pt and Lewis acid of MCM-41 (Al) promotes the selectivity of carboxylic acids by preventing the cleavage of the C-C bond of polyols. The conversion of glycerol and the selectivity of glyceric acid were 72.2 and 77.9%, respectively, over 3 wt % Pt/MCM-41 catalyst (Si/Al ratio, 70) at 60 degrees C and 1 MPa O-2. In addition, the location and number of hydroxyl groups also affect the catalytic oxidation activity. The insights may provide new suggestions on design of the bifunctional Pt-Lewis catalyst for the selective oxidation of alcohols.