Preparation of tin dioxide nanotubes via electrosynthesis in a template

A gold electrode modified with a porous polycarbonate membrane was immersed in an aqueous tin chloride solution. Electrochemistry was employed to control the local pH within the pores and drive a precipitation reaction. Removal of the gold and dissolution of the polymer yielded 1-dimensional polycrystalline tin oxide particles, the crystallinity of the material was enhanced by annealing at 650 degrees C in ambient. Scanning electron microscopy indicated that the diameter of the as-prepared 1-dimensional tin oxide nanoparticles matched the diameter of the pores in the membrane, 100 nm, and the length, between 0.4 and 1.4 mu m, was dependent on the charge passed. High resolution transmission electron microscopy indicates that the particles were hollow, with a wall thickness of approximately 10 nm. The formation of nanotubes results from continuous side-wall precipitation along a reaction front.