Promoted catalytic performance of Ni-SBA-15 catalysts by modifying with Fe and Cu for hydrogenation of levulinic acid to gamma-valerolactone

Abstract

A series of Ni-based SBA-15 catalysts were prepared via a wet impregnation method and tested for hydrogenation of levulinic acid (LA) to γ-valerolactone (GVL). A GVL yield of 56% was obtained over Ni-SBA-15 catalyst and the GVL yield increased to 64% as the addition of Fe. Compared with the results above, a better performance with 93% GVL yield was obtained over the Ni–Fe–Cu/SBA-15. Extensive catalysts characterization techniques including TPR, XRD, XPS and porosity analysis have been performed to study the nature of nickel-based catalysts. Porosity analysis and XRD showed that all the studied catalysts had a typical mesoporous texture. The TPR and XPS results indicated that there was a strong interaction among Ni, Fe and Cu species and the nickel species was relatively enriched on the surface of the catalysts, which could be accounting for the highest catalytic performance of the Ni–Fe–Cu–SBA-15 catalyst with GVL yield of 93%. In addition, the reaction parameters such as temperature, time, catalysts loading and H₂ pressure have been systematically optimized, giving a near quantitative yield of GVL over Ni–Fe–Cu/SBA-15 in the presence of the reaction temperature of 200 °C, time of 5 h, mass ratio of catalyst/reactant LA 0.3 and H₂ pressure of 3.0 MPa.