Self-Assembly Hierarchical Silica Nanotubes with Vertically Aligned Silica Nanorods and Embedded Platinum Nanoparticles

We report a simple method for the fabrication of hierarchical silica-Pt nanotubes. In the system, initial Pt NPs can be obtained via the reduction of H₂PtCl₆ with trisodium citrate as reductant. The self-assembled SiO₂@Pt@SiO₂ spheres were stuck together and etched through the “surface-protected etching” strategy. Many vertically aligned silica branches in situ grew from the inlaid SiO₂@Pt@SiO₂ spheres, fabricating the hierarchical silica-Pt nanotubes automatically. TEM and SEM were conducted to monitor the morphological evolution. The effects of the PVP concentration and molar ratios of NH₄OH to TEOS have also been investigated with a series of contrast experiments. Furthermore, in this work, several potential applications of HSNs have been investigated, such as the synthesis of Pt-CeO₂ nanotubes and other single or double metal nanotubes. Besides, the hierarchical silica-Pt nanotubes exhibited a high thermal stability and excellent catalytic performance in the reaction of propane dehydrogenation, suggesting their potential application in various high-temperature reactions.