Propene epoxidation with H2 and O2 on Au/TS-1 catalyst: Cost-effective synthesis of small-sized mesoporous TS-1 and its unique performance

Abstract

Designing cost-effective titanium silicalite-1 (TS-1) with enhanced mass transfer ability is of prime scientific and industrial importance. In this work, a novel small-sized mesoporous TS-1 (STS-1) material is first synthesized in cheap TPABr system using steam-assisted crystallization method. Compared with cheap microporous TS-1 prepared by classical hydrothermal method (HTS-1) with particle size of 950 nm, STS-1 shows mesoporous character of 13 nm and reduced average particle size of 590 nm. Moreover, effect of TPABr concentration is systematically investigated, and both of insufficient and overmuch TPABr concentrations are unfavorable because of low crystallinity and exorbitant price, respectively. Importantly, the catalytic performance of cost-effective Au/STS-1 for direct propene epoxidation with H2 and O2 is much better than that of Au/HTS-1, and comparable to the performance of the expensive Au/TS-1. By multi-characterizations and activation energy analysis, the underlying mechanism for the enhanced performance is further discussed. This work sheds new light on the design and synthesis of highly effective and cost-efficient TS-1 catalysts.