Preparation of Ni-Al2O3 Catalysts Derived from Hydrotalcite and Its Catalytic Performance for Hydrogenation of Levulinic Acid

A series of Ni-Al2O3 catalysts with different Ni/Al molar ratios was prepared using NiAl-NO3-LDH as precursors and characterized by means of N-2-physical adsorption, ICP.OES, TG/DTG, XRD, XPS, H-2-TPR/TPD and NH3-TPD techniques. The catalytic performance of these catalysts for liquid phase hydro. genation of levulinic acid was valuated. The results demonstrated that with the increasing of Ni/Al molar ratio, isolated gamma-AlOOH species evolved dissociative Ni(OH)(2) which existed in the hydrotalcite.like laminate struc. ture, the interaction between metal.support in catalyst become weaker, the dispersion of Ni species decreased, surface acidic sites increased first and then decreased. When Ni/Al molar ratio is 3, the catalyst had the most abundant acidic and hydrogenation sites and exhibited the high performance for the hydrogenation of levulinic acid to gamma-valerolactone. 92.7% yield of gamma-valerolactone was obtained under the condition of 160 degrees C, 4 MPa H-2 pressure.