Efficient Cu-Co bimetallic catalysts for the selective hydrogenation of furfural to furfuryl alcohol

Abstract

It has important research value for effectively upgrading furfural (FAL) to furfuryl alcohol (FOL) with cheap metals. In this work, a series of layered double hydroxides (LDH) derived CunCo1/MgAlOx (n = 1, 2, 3, and 4) catalysts with different metal ratios were prepared by a simple one-pot method and applied in FAL hydrogenation to FOL. It was found that the synergistic interaction between Cu and Co significantly improves the catalyst activity and favors the formation of Cu2O, which can act as a Lewis acid site and polarize the carbonyl group (C = O), thus promoting the formation of FOL. And in-situ DRIFTS shows that the Cu3Co1/MgAlOx preferentially adsorbs and activates C = O rather than furan rings. Moreover, DFT calculations show that the Cu3Co1 (111) crystal surface with the lowest d-band center and the strongest synergistic interaction between Cu and Co exhibits the highest adsorption energies of H2 and FAL, the lowest adsorption energies of H* and FOL, and the lowest energy barriers of FAL to alkoxy intermediate that is conducive to form FOL. Herein, as a favorable contender for efficient hydrogenation of FAL to FOL, the Cu3Co1/MgAlOx gives a 99.9% yield to FOL and presents excellent cycling stability.