Alcohol-Assisted Salt-Spreading Synthesis of Single-Atom Zirconium Catalysts on Ultrathin 2D MWW Zeolite for Enhanced Biomass Valorization.

Abstract

The precise synthesis of single-atom Zr catalysts on ultrathin 2D MWW zeolites remains challenging due to inevitable Zr clustering, expensive precursors, and complex post-treatments. Here, an alcohol-assisted salt-spreading deposition (ASD) strategy is reported to immobilize atomically dispersed Zr sites on pre-synthesized single-layer MWW nanosheets (SL-MWW). Derive benefit from the abundant external silanol groups (SiOHext) on the external surface of ultrathin 2D-MWW, tetracoordinated Zr─O4 configurations are grafted via a facile ASD process without toxic organic solvents. Characterizations including HAADF-STEM and XAS confirm the atomic dispersion and unique tetracoordinated structure of the Zr site. The resulting Zr-SL(ASD) catalyst exhibits exceptional Lewis acidity and accessibility, achieving superior selectivity and high conversion in Meerwein-Ponndorf-Verley reduction and etherification (MPV-ETH) cascade reaction of α, β-unsaturated carbonyl compounds and transesterification to valorized biomass under mild conditions. Comparative studies reveal three possible interaction pathways between external silanol groups and Zr species that govern atomic dispersion. The ASD approach successfully eliminates expensive and toxic organometallic precursors or energy-intensive treatments, offering a green and scalable route to prepare single-atom Zr-MWW catalysts. This work provides new insights into designing efficient and sustainable zeolite-based catalysts for biomass valorization.