Alkaline-Assisted Excessive Impregnation for Enhancing Au Nanoparticle Loading on the TS-1 Zeolite

Abstract

Direct epoxidation of propylene (C₃H₆) with hydrogen (H₂) and oxygen (O₂) over the Au/TS-1 catalyst is known as the “Holy Grail” reaction for propylene oxide (PO) synthesis. However, Au nanoparticle loading on TS-1 was limited by traditional deposition precipitation, impregnation and could not achieve ideal catalytic results. In this report, alkaline-assisted excessive impregnation helped to remove Cl^– from the Au impregnation precursor, improve the loading efficiency of Au nanoparticles and overcome the abnormal growth of nanograins. Better hydrophobicity, surface acidity and an oxygen-containing free radical environment helped Au/TS-1-AEI achieve much better C₃H₆ conversion (8.0%), PO selectivity (96.7%) and stability (>100 h).