Straightforward synthesis of beta zeolite encapsulated Pt nanoparticles for the transformation of 5-hydroxymethyl furfural into 2,5-furandicarboxylic acid

Encapsulating noble metal nanoparticles (NPs) within the zeolite framework enhances the stability and accessibility of active sites; however, direct synthesis remains a challenge because of the easy precipitation of noble metal species under strong alkali crystallization conditions. Herein, beta zeolite-encapsulated Pt NPs (Pt@Beta) were synthesized via a hydrothermal approach involving an unusual acid hydrolysis preaging step. The ligand—(3-mercaptopropyl)trimethoxysilane—and Pt precursor were cohydrolyzed and cocondensed with a silica source in an initially weak acidic environment to prevent colloidal precipitation by enhancing the interaction between the Pt and silica species. Thus, the resultant 0.2%Pt@Beta was highly active in the transformation of 5-hydroxymethylfurfural into 2,5-furandicarboxylic acid (FDCA) under atmospheric O₂ conditions by using water as the solvent while stably evincing a high yield (90%) associated with a large turnover number of 176. The excellent catalysis behavior is attributable to the enhanced stability that inhibits Pt leaching and strengthens the intermediates that accelerate the rate-determining step for the oxidation of 5-formyl-2-furan carboxylic acid into FDCA.