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pubs.acs.org/doi/abs/10.1021/jp106690q

The synthesis of well-defined silica nanotubes and Pd nanoparticle-decorated silica nanotubes is reported. The synthesis of silica nanotubes involves (1) formation of a 1-D template of the core−corona threadlike micelles through self-assembly of poly(ethylene glycol)-block-poly(4-vinylpyridine) in water, (2) a directed surface sol−gel process of tetraethylorthosilicate (TEOS) on the template of the threadlike micelles, and (3) calcination to remove the template. Because of the inherently pendent catalyst sites of the poly(4-vinylpyridine) block on the threadlike micelles, the surface sol−gel process is directed onto the template, and therefore, formation of irregular silica aggregates is avoided. Following the proposed method, well-defined silica nanotubes with thicknesses ranging from 3 to 17 nm are produced by changing the weight ratio of TEOS/micelles. Also benefiting from the chelate poly(4-vinylpyridine) block, Pd nanoparticles are introduced into the cavum of silica nanotubes initially through coordination between the poly(4-vinylpyridine) block with the Pd precursor, followed by reduction with NaBH₄ aqueous solution.