WO3–ZrO2–TiO2 Composite Oxide Supported Pt as an Efficient Catalyst for Continuous Hydrogenolysis of Glycerol

Abstract

Two series of WO3–ZrO2 and WO3–ZrO2–TiO2 composite oxides were prepared via an Evaporation Induced Self Assembly (EISA) method and applied for the hydrogenolysis of glycerol after loading with Pt. Several techniques like XRD, BET, Raman spectroscopy, NH3-TPD, Py-IR, TEM and XPS were adopted to characterize the physicochemical properties of the as-synthesized catalysts. The structure and catalytic activities of these catalysts were significantly affected by the calcination temperature of the composite oxides. The introduction of TiO2 into Pt/WO3–ZrO2 could inhibit the drastic decrease in catalytic performance due to the formation of inactive crystalline WO3 under high calcination temperature of 800 ℃. A maximum activity was obtained on the Pt/WO3–ZrO2–TiO2 catalyst when the calcination temperature was 600 ℃, which gave 73.8% glycerol conversion and 25.4% 1,3-propanediol yield. While the Pt/WO3–ZrO2 catalyst only exhibited 53.4% glycerol conversion and 20.2% 1,3-propanediol yield. The enhanced activity of Pt/WO3–ZrO2–TiO2 was ascribed to the improved acidity originating from (i) higher acidic properties of WOx species when linked to Ti with larger electronegativity other than Zr and (ii) new acid centers caused by heteroatoms linkage as the combination of ZrO2 and TiO2. The effects of Pt loading amount and reaction temperatures were also investigated.