A reliable protocol for fast and facile constructing multi-hollow silicalite‑1 and encapsulating metal nanoparticles within the hierarchical zeolite

Abstract A facial and cost-effective protocol preparing multi-hollow silicalite-1 (S-1) zeolite was proposed. That is, treating the parent zeolite with tetrapropylammonium hydroxide (TPAOH) solution at low temperature for a period prior to recrystallization. In this protocol, the geometric structure of the product could be highly controlled from hollow to sponge-like multi-hollow configuration, by modulating the period. It was demonstrated that the key role of this step performed before the recrystallization is to create some deep gullies on the parent zeolite that are necessary for constructing the desired multi-hollow structure. This strategy was also succeeded for fast confining single- or bi-metal nanoparticles in much high dispersion within the multi-hollow S-1 without any protective agent addition. It was proved that this protocol is very effective for dispersing Pt within the sponge-like S-1, even for preparing the Pt@S-1 composite with the Pt content as high as 1.67 wt.%. As a specialty of the protocol, it is that, the protocol always gives desired open mesopores to the product material. The Pt@S-1 and PtSn@S-1 exhibited much higher activity for CO oxidation and propane dehydrogenation than the corresponding conventional catalysts.