Effect of WOx Doping into Pt/SiO2 Catalysts for Glycerol Hydrogenolysis to 1,3-Propanediol in Liquid Phase

Abstract

Direct hydrogenolysis of glycerol to 1,3-PDO is a cost-effective solution to both production of 1,3-PDO with an increasing industrial demand and valorization of the biomass-derived glycerol, and the oxophilic tungsten oxide was found beneficial to the selective formation of 1,3-PDO from glycerol combined with platinum group metals. However, role of tungsten oxide on the structure, properties and catalytic performances has remained unsolved. Pt-WOx/SiO2 catalysts were prepared by a sequential impregnation method, and the resulting samples were systematically characterized and their catalytic performances were probed by selective hydrogenolysis of glycerol to 1,3-PDO in liquid phase. There was a strong interaction found between the tungsten oxide species and the metallic platinum on the synthesized Pt-WOx/SiO2. A non-stoichiometric ratio of WOx was detected and the polytungstate were predominating on the optimized Pt-10WOx/SiO2 catalyst, and a rather high ratio of W5+ species and the possible oxygen vacancies were suggested. WOx doping enhanced the surface acidity of Pt/SiO2 and promoted the dispersion degree of metallic platinum on it. The glycerol conversion and 1,3-PDO selectivity can be markedly improved by WOx doping into Pt/SiO2 catalysts, and the enhancement in the selectivity to 1,3-PDO was believed to proceed by restraining the transformation of 1,3-PDO to 1-propanol.