Regulating oxygen defects via atomically dispersed alumina on Pt/WO_x catalyst for enhanced hydrogenolysis of glycerol to 1,3-propanediol

Tungsten-based catalyst has been widely investigated in the field of selective hydrogenolysis of secondary C–O bond, such an important yet challenging strategy, in glycerol conversion, in which the product 1,3-propanediol (1,3-PDO) is of great value in polyester industry. Unfortunately, though it has been proved to be highly active, the identification of the intrinsic tungsten oxide active sites still remains unrevealed to date due to its complex microstructure. Herein, we incorporate atomically dispersed alumina as promoter in the context of the selective hydrogenation of glycerol and report a Pt/Al-WO_x catalyst. This catalyst decidedly outperforms the unpromoted Pt/WO_x, which elevates the 1,3-PDO yield to 2 times. Spectroscopy characterizations and chemisorption experiments have revealed that the high activity and selectivity of Pt/Al-WO_x catalyst results from the more oxygen vacancies on WO_x in-situ generation by the acceleration of atomically dispersed alumina in hydrogen atmosphere, which increases the selective adsorption of glycerol and the in-situ Brønsted acid sites for the selective activation of secondary C–O bonds, thus largely augmenting the hydrogenolysis performance. This discovery not only provides the new strategy of defect engineering to enhance hydrogenolysis performance of secondary C–O bond in biomass compounds, but reveals the unique role of the unsaturated coordination structure of WO_x in chemoselective hydrogenolysis reactions.