Salt-assisted deposition of SnO2 on α-MoO3 nanorods and fabrication of polycrystalline SnO2 nanotubes

Rutile-like tin dioxide (SnO2; tetragonal symmetry) is a strategic material for a wide range of important applications. Although numerous methods have been developed for preparations of SnO2 nanoparticles, nanowires, and nanorods, there has been no rational synthetic method reported to prepare this functional material into tubular nanostructures. In this article, we describe a facile template method for synthesis of free-standing polycrystalline SnO2 nanotubes in aqueous solution. With soluble alpha-MoO3 nanorod templates, polycrystalline SnO2 can be first deposited under normal atmospheric pressure (room temperature to 100 degreesC) or hydrothermal conditions (180 degreesC). In particular, salt additives such as Na2SO4 have been proven to be indispensable for the deposition of Sno(2) skins. Various preparative parameters have been examined in detail, and dissolution modes Of alpha-MoO3 have also been investigated to address the formation mechanism. The optical band gap determined for the nanotubes is 3.92 eV (for crystallites with an average size of similar to4 nm). This salt-assisted one-pot method promises large-scale production of polycrystalline SnO2 nanotubes with both structural engineering and crystallite size control.