Ni-Al-Ti Hydrotalcite Based Catalyst for the Selective Hydrogenation of Biomass-Derived Levulinic Acid to γ-Valerolactone

Ni-Al-Ti mixed oxide derived from Ni-Al-Ti hydrotalcite precursor is identified as an efficient catalyst for the hydrogenation of levulinic acid (LA) to gamma-valerolactone (GVL). This catalyst showed high active surface Ni sites due to a higher synergy in the mixed oxide formed from the hydrotalcite precursor. These results are further supported by X-ray diffraction analysis (XRD), electron spin resonance spectroscopy (ESR) and scanning electron microscopy (SEM) results. The higher activity of Ni-Al-Ti compared to Ni-Al, Ni-Ti catalysts was attributed to a high ratio of Lewis to Bronsted acid sites (LAS/BAS) observed from pyridine adsorption - DRIFTS results along with high surface Ni sites on the catalyst surface measured from CO-chemisorption studies. This contributed to the enhanced selectivity of the desired product, GVL over Ni-Al-Ti catalyst as compared to its individual counter parts, Ni-Ti and Ni-Al catalysts.