Insight into the Role of Unsaturated Coordination O2c-Ti5c-O2c Sites on Selective Glycerol Oxidation over AuPt/TiO2 catalysts

In this work, we synthesized a series of TiO2 enclosed with different terminated facet and investigated the catalytic performance on glycerol oxidation catalysts over Au1Pt3/TiO2 under base–free condition. To our surprise, Au1Pt3/TiO2 catalyst presented the support facet–dependent catalytic performance. Different TiO2 crystal planes apparently affect the oxidation products distribution especially the selectivity of glyceraldehyde and glyceric acid but have inconspicuous influence on activity of glycerol oxidation. Primarily, the coordination unsaturated sites O2c–Ti5c–O2c of (001) facet highly dissociated C=O bond of aldehyde group in a bidentate form characterized by in–situ CO2 and formaldehyde Fourier Transform Infrared Spectroscopy. In another aspect, Auδ+ species were generated on the interface between AuPt nanoparticles and the (001) facet of TiO2 due to the strong interaction, which facilities the insertion of oxygen species during the process of oxidation to glyceric acid. With the aid of bidentat...