Influence of Lewis acid on activity and selectivity of Pt/MCM-41 (Al) catalysts for oxidation of C3 polyols in base-free medium

Abstract: The nature of solid support is crucial for 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 C3-polyols in base-free medium. Catalyst characterizations (e.g., HAADF-STEM and XPS) and DFT calculation 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 C-C bond of polyols. The conversion of glycerol and the selectivity of glyceric acid were 72.2% and 77.9%, respectively, over 3wt% Pt/MCM-41catalyst (Si/Al ratio: 70) at 60 oC, 1 MPa O2. In addition, the location and number of hydroxyl groups also affect the catalytic oxidation activity. The insights may provide new suggestions on design of bifunctional Pt-Lewis catalyst for the selective oxidation of alc...