Promoting effect of boron oxide on Cu/SiO2 catalyst for glycerol hydrogenolysis to 1,2-propanediol

•B2O3 can promote the dispersion of copper species and stabilize copper particles.•Addition of B2O3 to Cu/SiO2 greatly enhanced activity and stability.•100% Conversion and 98.0% 1,2-propanediol selectivity were achieved over 3CuB/SiO2.•1,2-Propanediol yield was proportional to Cu specific surface area.•Glycerol hydrogenolysis is a structure-sensitive reaction.

Cu/SiO2 catalyst has been extensively applied in glycerol hydrogenolysis for its high selectivity to 1,2-propanediol, while suffering from severe deactivation easily. B2O3 is frequently used as an additive for stabilizing active species. Thus, a series of Cu/SiO2 catalysts with various B2O3 loadings for glycerol hydrogenolysis were prepared via precipitation-gel method followed by impregnation with boric acid. These catalysts were fully characterized by ICP, BET, XRD (in situ XRD), N2O chemisorption, H2-TPR, NH3-TPD, IR, Raman, XPS, and TEM. Addition of B2O3 to Cu/SiO2 can greatly restrain the growth of copper particles and promote the dispersion of copper species upon calcination, reduction and reaction, which resulted in the enhanced catalytic activity and stability. The optimal 3CuB/SiO2 reached complete conversion with 98.0% 1,2-propanediol selectivity. The strong correlation between 1,2-propanediol yield and Cu surface area gave direct evidence that the active Cu species were the primary active sites for glycerol hydrogenolysis.

Graphical abstractDoping B2O3 to Cu/SiO2 catalyst significantly improved activity and long-term performance for glycerol hydrogenolysis to 1,2-propanediol. The strong correlation between 1,2-propanediol yield and Cu surface area gave direct evidence that Cu surface area was a key parameter for developing fundamental mechanistic insight into the performance of glycerol hydrogenolysis over Cu-based catalyst.Figure optionsDownload full-size imageDownload high-quality image (126 K)Download as PowerPoint slide