Optimizing CuNi catalysts for long-term vapor phase hydrogenation of levulinic acid to γ-valerolactone: Influence of the support on activity and stability

The conversion of biomass-derived levulinic acid (LA) to gamma-valerolactone (GVL) is crucial for sustainable chemical and fuel production. This study evaluates the vapor phase hydrogenation of LA using Cu-Ni bimetallic catalysts supported on various metal oxides and their impact on the pathways of LA conversion. Specifically, we examine the influence of AlO2, SiO2, ZrO2-SiO2, and CeO2-SiO2 on catalyst performance and stability. Cu-Ni catalysts supported on SiO2 modified with citric acid (SiO2-CA) exhibited superior stability, while the one supported on Al2O3 showed higher activity. The enhanced performance of the SiO2-CA-supported catalyst is attributed to its moderate acidity (379.3 mu mol/gcat) and resistance to sintering. Stability tests reveal that although both CuNi/ Al2O3 and CuNi/SiO2-CA catalysts deactivate over time, the latter demonstrates slower deactivation and better reactivation potential, maintaining conversion close to 80 % for 42 h. The study highlights the role of support in optimizing catalytic performance for LA hydrogenation.