Abstract
Bimetallic Ru–Re/SiO 2 and monometallic Ru/SiO 2 catalysts were prepared by impregnation method and their catalytic performances were evaluated in the hydrogenolysis of glycerol to propanediols (1,2-propanediol and 1,3-propanediol) with a batch type reactor (autoclave) under the reaction conditions of 160 °C, 8.0 MPa and 8 h. Ru–Re/SiO 2 showed much higher activity in the hydrogenolysis of glycerol than Ru/SiO 2, and the pretreatment conditions of the catalyst precursors had great influence on the catalytic performance of both Ru–Re/SiO 2 and Ru/SiO 2 catalysts. The physicochemical properties of Ru–Re/SiO 2 and Ru/SiO 2, such as specific surface areas, crystal phases, morphologies/microstructures, surface element states, reduction behaviors and dispersion of Ru metal, were characterized by N 2 adsorption/desorption, XRD, Raman, TEM–EDX, XPS, H 2-TPR and CO chemisorption. The results of XRD, TEM–EDX and CO chemisorption characterizations showed that Re component had an effect on promoting the dispersion of Ru species on the surface of SiO 2, and the measurements of H 2-TPR revealed that the co-existence of Re and Ru components on SiO 2 changed the respective reduction behavior of Re or Ru alone. High pre-reduction temperatures would decrease the activities of Ru–Re/SiO 2 and Ru/SiO 2 catalysts, compared with the corresponding calcined catalysts (without pre-reduction), which actually went through an in-situ reduction during the reaction. XPS analysis indicated that Ru species was in Ru 0 metal state, while Re species was mostly in Re oxide state in the spent Ru–Re/SiO 2 sample. Re component was probably in rhenium oxide state rather than Re 0 metal state to take part in the reaction via interaction with Ru 0 metal.
Published Version
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