Chemoselective Oxidation of Glycerol over Platinum-Based Catalysts: Toward the Role of Oxide Promoter

The metal oxide promoters remarkably enhance the catalytic activity of supported Pt catalysts in the glycerol oxidation toward glyceric acid, whereas the primary factor that metal oxide promotes the reaction, as well as the kinetics relevant step remain indistinct. Herein, manganese dioxide (MnO₂) is chosen as a model to uncover the role of promoter in the glycerol oxidation over Pt-based catalyst in alkali-free solution. The results prove that the superior catalytic performance is mainly attributed to the increased synergistic interaction between Pt particles and the metal oxides to boost the activation of oxygen (not glycerol), while the increased dispersion shows slight effect. Furthermore, the detailed kinetic studies reveal that MnO₂ is prone to accelerate the awkward step of glyceraldehyde to glyceric acid, and the lattice oxygen of MnO₂ also involves in this particular step.