Breaking the Activity‐Selectivity Trade‐off in Direct Levulinate Hydrodeoxygenation to Pentanoic Biofuels over La‐Modulated Ru‐Zeolite Catalysts

Disentangling the activity-selectivity trade-off in hydrodeoxygenation (HDO) of biomass-derived oxygenates has been a great challenge in biomass valorization and related tandem catalysis, by virtue of involving a series of reactions in parallel and in cascade. Herein, we demonstrate the importance of La modulation for Ru-zeolite combinations in the case of direct HDO of neat ethyl levulinate (EL) into ethyl pentanoate (EP). An unprecedented EP yield of 80% and an EP turnover rate (TOR) of 224 mol_EP·mol_Ru ^-1·h^-1, together with excellent stability, were obtained for the optimal Ru/2.8La-Y catalyst for the first time, compared to the current reported "performance ceiling" of EP yields of <40% and EP TORs of <120 mol_EP·mol_metal ^-1·h^-1 under similar conditions. Optimal La modulation could maximize the density of the active Brønsted acid sites and efficiently attenuate the acid strength, thus enhancing both activity and selectivity in the direct HDO of EL into EP while suppressing the further hydrolysis reactions that consume EP. This study provides an effective approach to regulate the acid properties of metal-zeolite bifunctional catalysts, in particular in mediation of compromise in acid density and acid strength factors, for breaking the activity-selectivity trade-off in biomass valorization and beyond.