SiO2 promoted Pt/WOx/ZrO2 catalysts for the selective hydrogenolysis of glycerol to 1,3-propanediol

•Addition of SiO2 to PtW/Zr greatly enhanced activity and 1,3-propanediol selectivity.•54.3% conversion and 52.0% 1,3-propanediol selectivity were achieved over 5PtW/ZrSi.•A model scheme of WOx transformation due to SiO2 doping has been built.•Pt and polytungstate have been identified as the dominant active phases.•Glycerol hydrogenolysis conforms to the dehydration–hydrogenation mechanism.

To improve 1,3-propanediol selectivity, a series of SiO2 modified Pt/WOx/ZrO2 catalysts with various SiO2 content for glycerol hydrogenolysis were prepared via deposition–precipitation method followed by sequential impregnation. These catalysts were systematically characterized using BET, ICP, CO chemisorption, XRD, H2-TPR, NH3-TPD, Raman, IR, TEM and XPS. The incorporation of suitable SiO2 into Pt/WOx/ZrO2 catalysts had extremely favorable effects on the dispersion of WOx and transformation from crystalline WO3 to active polytungstate, while superfluous SiO2 converted polytungstate to monotungstate. Among them, the 5PtW/ZrSi catalyst reached superior activity and maximum 1,3-propanediol selectivity, up to 52.0%. The structure-activity correlation indicated that glycerol hydrogenolysis conformed to dehydration–hydrogenation reaction mechanism and found that Pt and polytungstate were the most active species.

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