Rare-Earth Metal Modified Co-Based Catalysts for Highly Selective Hydrogenation of Furfural to 1,5-Pentanediol

Abstract

The ability to effectively control furan ring opening is the key to transforming furfural into 1,5-pentanediol. Herein, a series of Co-based catalysts modified with rare-earth metals (Y, Pr, La, and Ce) were synthesized. It was found that Y-modified Co-based catalyst with a Co/Y molar ratio of 3.5/0.5 exhibited the highest selectivity for 1,5-pentanediol (53.7%) at 150 °C and 4 MPa H₂ in isopropanol (time = 5 h). Coordination between Co and Y in the catalyst resulted in more CoO_x and oxygen vacancies, which are vital factors for cleaving the C–O bond of the furan ring. In addition, highly dispersed small-sized Co⁰ particles on the catalyst surface could boost the dissociation of H₂ molecules, which attacked the carbonyl group in the furan ring of furfural to afford 1,5-pentanediol. Density functional theory calculations revealed that the presence of CoO_x/Y₂O₃ oxide interfaces promoted adsorption of furfural (especially via the furan ring) and hydrogenolysis during the hydrogenation process. Modifying a Co-based catalyst with rare-earth metals offers a novel approach for producing 1,5-pentanediol from furfural.