Facile synthesis of a high-efficiency NiFe bimetallic catalyst without pre-reduction for the selective hydrogenation reaction of furfural

Abstract

A high-efficiency nickel–iron bimetallic catalyst (Ni₃Fe₁ alloy) was synthesized by a facile solvothermal reaction and directly used in furfural hydrogenation without pre-reduction. When the total metal acetate was 6 mmol (Ni : Fe = 4 : 2) with 2 mmol sodium acetate under reaction conditions of 1 MPa H₂ pressure at 130 °C for 1 h, the conversion for furfural and selectivity for furfuryl alcohol were both more than 98%. XRD, BET, H₂-TPD, SEM, HRTEM, EDS, ICP-MS and ex/in situ XPS were used to characterize the catalysts. Compared to the monometallic Ni catalyst, the introduction of Fe not only enhanced the hydrogen adsorption capacity of Ni but also forms NiFe₂O₄ on the surface of the catalyst to protect the internal crystals from further oxidation and maintain hydrogenation ability. Moreover, the introduction of Na increased the purity of the Ni₃Fe₁ crystal of the catalyst and reinforced the interaction between Ni and Fe, resulting in an improvement in hydrogenation performance. Based on density functional theory (DFT) calculations, the reaction mechanism was systematically investigated. The results of five recycling tests show excellent catalyst stability. The environmentally friendly synthetic process, high stability, catalytic efficiency and the ability to function without a pre-reduction step make the nickel–iron bimetallic catalyst an ideal, commercial candidate for the furfural hydrogenation reaction.