Synergistic Catalysis over Silanol Nests-Anchored Sn-In FAU Zeolite for Efficient Cascade Conversion of Levulinic Acid to γ-Valerolactone.

The upgrading of biomass feedstocks represents a promising strategy to reduce excessive reliance on fossil fuels and counteract the persistent increase in atmospheric carbon dioxide concentrations. The one-pot catalytic conversion of biomass-derived compounds into γ-valerolactone constitutes a pivotal advancement toward the efficient valorization of lignocellulosic biomass. Nevertheless, achieving high-efficiency conversion under scalable reaction conditions remains a significant scientific challenge. In this study, we report a rational design of bimetallic Sn-In catalysts confined within FAU zeolites, leveraging the anchoring effect of silanol nests. A systematic evaluation of catalytic performance across various metal ratios, coupled with comprehensive characterization analyses, revealed a synergistic catalytic mechanism: Sn selectively activates the substrate's carbonyl group, whereas In species effectively fine-tune the acid-base properties of the catalyst and realize the regulation of the intermediate reaction path. Under the optimized reaction conditions, levulinic acid conversion exceeded 99.9%, with a γ-valerolactone yield of 87.89 ± 0.86%. This study advances fundamental understanding of zeolite-based materials in green catalytic conversion of biomass-derived feedstocks and provides useful insights into the structure-activity correlations for bimetallic zeolite catalysts.