Highly efficient Ni–Mn/SiO2 catalyst for the selective hydrogenation of biomass-derived levulinic acid to γ-valerolactone under mild conditions

Abstract

Hydrogenation of levulinic acid (LA) to γ-valerolactone (GVL) is a key reaction in the conversion of biomass to renewable fuels and value-added chemicals. Developing low-cost, highly efficient and reusable non-noble metal-based heterogeneous catalysts is vital but challenging. Herein, non-noble Ni–Mn/SiO₂ catalysts with a low Ni loading (2.0 wt%) were designed for the selective hydrogenation of LA to GVL. The results showed that the optimal Ni–Mn/SiO₂ (Ni/Mn = 2) catalyst with well-dispersed and small-sized metal nanoparticles (2.21 nm) and moderate acid sites exhibited excellent activity and selectivity and achieved a 100% yield of GVL in a 1,4-dioxane solvent under mild reaction conditions (e.g., 0.8 mol% Ni, 140 °C and 2.0 MPa H₂) for 5.5 h and a 100% GVL yield at 180 °C for 2 h with a turnover frequency (TOF) of 190.2 h⁻¹, which is better than most non-noble metal catalysts reported. Furthermore, the catalyst exhibited excellent reusability and could be recycled at least five times with only slight activity loss. This work provides new insights for the rational design of highly efficient and stable non-noble metal catalysts for the conversion of LA to GVL.