Tuning Y-zeolite based catalyst with copper for enhanced activity and selectivity in vapor phase hydrogenolysis of glycerol to 1,2-propanediol

Abstract

Highly dispersed copper oxide species supported on a Y-zeolite with different Si/Al ratios (5.1, 12, 30, and 60) were synthesized by an incipient wet impregnation method. The catalysts were characterized by X-ray diffraction (XRD), N2 adsorption (BET), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV–vis diffused reflectance spectroscopy (UV-DRS), N2O chemisorption, Pyridine-adsorption Fourier transform Infrared Spectroscopy (Py-FTIR), NH3 temperature programmed desorption (NH3-TPD) and temperature programmed reduction (TPR). Copper dispersion and metallic area were measured by the N2O decomposition method. The amount of Bronsted and Lewis acidic sites was analyzed by Pyridine adsorption followed by FT-IR. Performance of the prepared catalysts in vapor phase hydrogenolysis of glycerol to 1,2-propanediol was evaluated by using a fixed-bed stainless-steel reactor at 0.2MPa and 210°C. The studies revealed that the 3wt.% CuO/Y-zeolite (Si/Al=5.1) catalyst was highly active in glycerol hydrogenolysis showing 92% conversion of glycerol and 83% selectivity to 1,2-propanediol. This seems to originate from high dispersion of Cu, smaller Cu crystallite size, and the presence of a high amount of surface beneficial acido-basic properties.