Engineering gold impregnated uncalcined TS‑1 to boost catalytic formation of propylene oxide

Abstract

Design and fabrication of highly efficient Au-based catalysts using simple impregnation method have been long sought-after. Herein, we report an efficient strategy to impregnate Au species onto uncalcined TS-1 using a sulphur-containing gold precursor, i.e., sodium dithiosulfatoaurate, for propylene epoxidation with H2 and O2 to produce propylene oxide (PO). Such catalyst delivers superior activity than the referenced catalyst prepared by impregnation using (sodium) aurichloride precursor and the catalyst prepared by deposition-precipitant urea (DPU) method. The catalyst structure-performance relationship is established by using multiple microscopy and spectroscopy techniques. The sulphur species contained in the Au precursor can serve as protecting-ligands, thus facilitating the formation of highly dispersed Au species on uncalcined TS-1. This finding may also provide a way for the preparation of highly efficient impregnated Au-based catalysts for other reactions.