One-dimensional carbon-SnO₂ and SnO₂ nanostructures via single-spinneret electrospinning: Tunable morphology and the underlying mechanism

Carbon-SnO₂ hybrid nanofibers with tunable morphology were prepared from polyacrylonitrile (PAN) and tin compounds via single-spinneret electrospinning and subsequent carbonization. Different tin compounds, including tin acetate (Sn(CH₃COO)₂), tin chloride dihydrate (SnCl₂·2H₂O), tin sulfate (SnSO₄) and tin sulfide (SnS), were chosen as precursors of SnO₂ to tune the morphology of carbon-SnO₂ nanofibers. Morphology of the obtained nanofibers was studied using a field emission scanning electron microscope (FESEM) and a transmission electron microscope (TEM), and their structures were characterized by thermal gravimetric analysis (TGA) and X-ray diffraction (XRD). A carbon-SnO₂ core-shell morphology is formed during carbonization when Sn(CH₃COO)₂ and SnCl₂·2H ₂O are used as precursors of SnO₂, while uniform distribution of Sn compounds in a carbon matrix is observed with SnSO ₄ or SnS as the precursor. Our study demonstrates that the Kirkendall effect, which is responsible for the formation of the core-shell morphology during carbonization, is strongly dependent on melting points and decomposition behaviours of the precursors. SnO₂ nanofibers and nanotubes with a high aspect ratio were produced upon burning out carbon, and their morphology is dependent on that of the corresponding hybrid nanofibers. TEM studies show that the SnO₂ nanofibers/nanotubes are constituted of SnO₂ single crystals, yet the grain size and facet varies with the precursor. The Brunauer-Emmett-Teller (BET) study verifies that the nanofibers/nanotubes have a large surface area, which also varies with the precursors used.