Gas phase dehydration of glycerol to acrolein over WO3/ZrO2 catalysts: Improvement of selectivity and stability by doping with SiO2

WO3/ZrO2 catalysts doped with SiO2 were shown to be more selective and stable catalysts than without SiO2 for dehydration of glycerol to acrolein at 300 °C. The catalysts prepared combining incorporation of siliceous species into ZrOx(OH)4-2x precursor and anionic exchange with peroxotungstate exhibited a selectivity to acrolein reaching 78% at nearly total glycerol conversion and a conversion of 82% was maintained after 177 h on stream. Characterization by several techniques (adsorption isotherms, XRD, Raman spectroscopy, XPS, NH3-TPD measurements) allowed to understand the origin of the improvement: the deposition of SiO2 on ZrO2 favored the formation of larger mesoporous pores and reduces the support basicity limiting the formation of by-products that can be coke precursors.

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► SiO2 doped WO3/ZrO2 catalysts were evaluated for dehydration of glycerol to acrolein.
► They were shown to be more selective and stable catalysts than without SiO2.
► Larger mesoporous pores were formed adding SiO2 leading to better stability.
► The support basicity was also reduced limiting the formation of coke precursors.