Enhanced stability for propene epoxidation with H2 and O2 over wormhole-like hierarchical TS-1 supported Au nanocatalyst

Abstract

Designing highly efficient Au/Ti-containing catalysts for propene epoxidation with H2 and O2 harbors tremendous scientific and industrial importance. In this work, novel hydrophobic hierarchical TS-1 (HTS-1) with wormhole-like mesopores (ca. 45 nm) and small crystal size (100 nm) is firstly synthesized by a two-step crystallization method using CTAB as template. Gratifyingly, the Au/HTS-1 catalyst shows simultaneously high PO formation rate of 150 gpoh−1kgCat−1 without any promoter additive, PO selectivity of 90% and impressive stability of 100 h, which are much better than traditional Au/TS-1 catalyst. Furthermore, the intrinsic reason for the enhanced performance is elucidated by multi-techniques such as N2 physisorption, HRTEM, TGA, FT-IR and 29Si NMR. Interestingly, it is found that the coke in 0.10 wt% Au/HTS-1 catalyst partly reside in mesopores, alleviating the deactivation of micropore blocking. Moreover, the enhanced mass transfer ability and higher hydrophobicity of Au/HTS-1 catalyst also lead to reduced coke weight and absence of aromatic coke.