Cooperative Surface Passivation and Hierarchical Structuring of Zeolite Beta Catalysts

Angew Chem Int Ed Engl. 2022 Oct 10;61(41):e202210434. doi: 10.1002/anie.202210434. Epub 2022 Aug 29.

Abstract

We report a method to prepare core-shell zeolite beta (*BEA) with an aluminous core and an epitaxial Si-rich shell. This method capitalizes on the inherent defects in *BEA crystals to simultaneously passivate acid sites on external surfaces and increase intracrystalline mesoporosity through facile post-hydrothermal synthesis modification in alkaline media. This process creates more hydrophobic materials by reducing silanol defects and enriching the shell in silica via a combination of dealumination and the relocation of silica from the core to the shell during intracrystalline mesopore formation. The catalytic consequences of *BEA core-shells relative to conventional analogues were tested using the biomass conversion of levulinic acid and n-butanol to n-butyl levulinate as a benchmark reaction. Our findings reveal that siliceous shells and intracrystalline mesopores synergistically enhance the performance of *BEA catalysts.

Keywords: Biomass Conversion; Core-Shell; Mesoporosity; Surface Passivation; Zeolite.