Effect of modified groups of carbon nanotubes on catalytic properties of Ru/CNTs catalysts for hydrogenolysis of sorbitol

Ruthenium catalysts supported on carbon nanotubes with different functional groups (MCN, AMCN and GMCN) were prepared by incipient wetness impregnation with ultrasonic-assistance and used for the hydrogenolysis of sorbitol. The catalysts were characterized by X-ray diffraction (XRD), HRTEM, X-ray photoelectron spectroscopy (XPS) and ICP-AES. The effects of functional group species, and base additives on the catalytic performance of Ru/CNTs in the sorbitol hydrogenolysis reaction were investigated. Nearly 99.5% of sorbitol conversion and 47.7% total yield of ethylene glycol and 1,2-propanediol (1,2-PD) could be achieved over Ru/AMCN under mild reaction conditions (205℃, 5.0 MPa), using Ca(OH)₂ as additive. The conversion of sorbitol and the selectivity to ethylene glycol (EG) and 1,2-propanediol (1,2-PD) did not decrease over the five repeated runs, which confirmed that the Ru/AMCN catalyst exhibited high stability in the aqueous hydrogenolysis of sorbitol to glycols.