Catalytic functionalities of nano Ru catalysts supported on TiO2-ZrO2 mixed oxide for vapor phase hydrogenolysis of glycerol to propanediols

摘要

Vapor phase hydrogenolysis of glycerol was studied over Ru catalysts supported on TiO2-ZrO2 binary oxide. Ru catalysts with various ruthenium loadings from 1.0 to 6.0 wt% were prepared by deposition-precipitation method on the TiO2-ZrO2 mixed oxide support. These catalysts were characterized by X-ray diffraction, H2 temperature-programmed reduction, NH3 temperature-programmed desorption, transmission electron microscopy, BET surface area, XPS and CO chemisorption measurements. The catalysts exhibited superior performance for the vapor phase hydrogenolysis of glycerol at moderate temperature and atmospheric pressure. The mixed oxide support plays a significant role in improving the catalytic activity for the production of propanediols. The glycerol conversion and the selectivity of various products depend on the catalyst preparation method and also on the Ru content. The influence of acidity of the catalyst and its correlation to the catalytic performance (selectivity and conversion) has been studied. The weak and strong acidic sites of the catalysts measured by NH3-TPD play a key role in selective formation of 1,2-propanediol and 1,3-propanediol. XRD, TEM, XPS and CO chemisorption studies revealed that ruthenium was well dispersed on TiO2-ZrO2 which further contributed to the superior catalytic activity for glycerol hydrogenolysis.