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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