Facile conversion of glycerol to 1,3-dihydroxyacetone by using mesoporous CuO–SnO 2 composite oxide supported Au catalysts

Selective catalytic oxidation of polyols, e.g., the selective catalytic oxidation of the secondary –OH bond in glycerol, remains a considerable challenge. In this study, a series of mesoporous CuO–SnO 2 composite oxides were prepared by a hard-template method and used to support Au catalysts for the selective oxidation of glycerol to 1,3-dihydroxyacetone (DHA) under base-free conditions. Catalysts with different Cu:Sn molar ratios gave different catalytic performances. A high conversion of glycerol (100%) and selectivity for DHA (94.7%) were obtained in 2 h at 80°C and P O2 = 1 MPa over the Au/CuO–SnO 2 -3:1 catalyst. Further investigation indicated that the high catalytic activity of Au/CuO–SnO 2 -3:1 is related to the small size and high dispersion of Au nanoparticles (NPs), the interactions between the Au NPs and the support, the synergistic effect between CuO and SnO 2 , and the amount of surface lattice oxygen species. Various reaction parameters, namely the glycerol:Au molar ratio, the reaction temperature, the initial O 2 pressure, the reaction time, and the support calcination temperature were studied. Although the conversion rate by the catalyst decreased after four cycles, the selectivity remained above 86%. Density functional theory calculations showed that the synergy between CuO and SnO 2 improves the catalytic activity in glycerol oxidation to DHA. The results show that mesoporous composite oxide supports have a wide range of potential applications in the selective oxidation of glycerol to other high-value-added products.