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 γ-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 AlO 2 , SiO 2 , ZrO 2 -SiO 2 , and CeO 2 -SiO 2 on catalyst performance and stability. Cu-Ni catalysts supported on SiO 2 modified with citric acid (SiO 2-CA ) exhibited superior stability, while the one supported on Al 2 O 3 showed higher activity. The enhanced performance of the SiO 2-CA -supported catalyst is attributed to its moderate acidity (379.3 µmol/g cat ) and resistance to sintering. Stability tests reveal that although both CuNi/Al 2 O 3 and CuNi/SiO 2-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. • CuNi catalysts were evaluated on various supports for efficient LA hydrogenation. • CuNi/Al 2 O 3 shows high GVL selectivity (97 %) at 200 °C, enhancing GVL production. • CuNi/SiO 2-CA was active and easy to reactivate, maintaining its activity by 42 h TOS. • CuNi/Al 2 O 3 suffered a more drastic deactivation, losing its activity after 6 h TOS. • Dual-oxide supports did not deliver remarkable activity or selectivity.