Ball-milling-induced phase transition of ZrO2 promotes selective oxidation of glycerol to dihydroxyacetone over supported PtBi bimetal catalyst

Catalytic oxidation of glycerol to dihydroxyacetone (DHA) represents an essential bio-upgrading process with industrial potential, and the challenging tasks are to control the selectivity for metal catalysts. This study provides insights into multiple positive roles of ball-milling-induced phase transition from tetragonal t-ZrO2 to monoclinic m-ZrO2 on activation of the secondary hydroxyl of glycerol over the bimetal PtBi/ZrO2 catalysts. The mZrO2-BM support affords enhanced both dispersion of the Bi-modified Pt sites and surface basicity than tZrO2 support, and therefore promotes the activity, DHA selectivity and recycling stability of the PtBi catalyst under neutral condition. Catalytic evaluation with DHA and glyceraldehyde as reactants and in-situ FT-IR spectra of isopropanol and acetone adsorption reveal that the catalyst prefers dissociative activation of the secondary hydroxyl of glycerol rather than the primary hydroxyl. The observations also demonstrate that DHA tends to be easily desorbed as target product for preventing deep oxidation or C–C cleavage into by-products.