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

Direct epoxidation of propylene (CH) with hydrogen (H) and oxygen (O) 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 CH conversion (8.0%), PO selectivity (96.7%) and stability (>100 h).