Electro-Assisted Synthesis of Sn-Beta Zeolite Leads to Record Tin Incorporation and Superior Lewis Acid Catalysis

Tin-incorporated zeolites represent a recognizable class of microporous materials widely used to handle biomass valorization and selective oxidation challenges. Sn-BEA is among the most catalytically valuable metallosilicates. However, in bottom-up synthesis, incorporation of the metal is hampered, narrowing the Lewis acid site density and, therefore, catalyst productivity. Here, we present a novel strategy for the hydrothermal preparation of Sn-BEA zeolite in hydroxide media employing our new Electro-Assisted Synthesis technique. Based on the controlled anodic release of Sn from a metal electrode in a crystallizing siliceous zeolite mixture, we can design tin-rich zeolites with record Si/Sn ratios as low as 14. The resulting Lewis acid characteristics are unparalleled for bottom-up Sn-BEA and the small crystals are beneficial in catalysis. One demonstration here in catalysis showed a 3-fold increased performance (per gram of zeolite) versus a classic fluoride-made material in triose sugar conversion. We hypothesize that both studied zeolites suffer from different types of mass transport limitations.