A vapor-solid strategy to silica sheathed metal nanostructures and microstructures via reactions of metal chlorides with silicon

A facile vapor-solid strategy has been developed to prepare silica-sheathed metal micro/nanostructures with controllable shapes. As examples, silica-sheathed nickel nanowires (diameter ∼50 nm), microcubes (edge length 1-3 μm), nanocubes (edge length ∼200 nm) with an epitaxial tail (diameter <100 nm), and 1D assembly structures of nanoparticles (particle diameter <100 nm) as well as silica-sheathed cobalt and copper micro/ nanostructures are synthesized. The possible reaction and growth mechanisms of Ni/SiO ₂ structures are discussed. The method is expected to be applied to a wider range of metals.