Integrating Zeolite and Layered Double Hydroxide for Highly Selective Catalytic Production of -Valerolactone

The production of gamma-valerolactone (GVL) from biomass derivatives levulinic acid (LA) based on acid-base metallic catalysts offers a sustainable pathway to the synthesis of valuable chemicals and biofuels. However, the development of efficient metallic catalysts with tunable Lewis acid-base and Br & oslash;nsted acid sites remains a challenge. Herein, for the first time, we integrated zeolite and layered double hydroxide (LDH), in a core-shell structure, wherein zeolite and CoFe-LDH provided the Br & oslash;nsted acidic sites and Lewis acid sites, respectively. Meanwhile, oxygen vacancies (OVx) acting as Lewis bases were generated on the surface of LDH via Ga doping. An efficient cascade catalytic reaction from LA to GVL was successfully achieved over the designed Beta@LDH-OVx catalyst, affording a superior conversion of LA (>99.9%) and an impressive selectivity to GVL (89.18%). Importantly, the "memory effect" of LDH endowed the catalyst with excellent regeneration of metal active sites. Density functional theory calculations revealed that the introduced OVx facilitated the adsorption of carbonyl oxygen in LA and boosted the production of GVL through the synergistic effect of acid/base sites in the composite catalyst. This work presents a rational design route for the construction of multifunctional catalysts by coupling zeolites and LDHs for highly selective catalytic conversion of biomass.