Influence of NaOH on the formation and morphology of Bi2Te3 nanostructures in a solvothermal process: From hexagonal nanoplates to nanorings

AbstarctHexagonal bismuth telluride (Bi2Te3) nanoplates and nanorings were synthesized by a simple solvothermal process. The composition, morphology and size of the as-prepared products were investigated by X-ray diffraction and transmission electron microscopy in detail. The systemically experiments have been performed to investigate the effect of alkaline additive NaOH on composition and morphology of Bi2Te3 nanostructures. The results indicate that alkaline additive NaOH is not necessary for the formation of Bi2Te3 nanostructures in a solvothermal process. However, NaOH plays an important role in determining the morphology and size of Bi2Te3 nanostructures. When the experiment was carried out with NaOH concentration ranging from 5 to 7 M, hexagonal Bi2Te3 nanoplates with edge length of 140–280 nm were synthesized. When the experiment was carried out at higher NaOH concentration of 9–11 M, hexagonal Bi2Te3 nanorings were fabricated by dissolving the inner part of the hexagonal nanoplates with NaOH for the first time. A possible formation mechanism has been proposed based on the experimental results and analysis. This work may open a new rational route for the synthesis of hexagonal Bi2Te3 nanorings which may have some scientific and technological applications in various functional devices.

► Bi2Te3 nanoplates and nanorings were synthesized by a simple solvothermal process.
► NaOH is not necessary for Bi2Te3 nanostructure growth in a solvothermal process.
► Hexagonal Bi2Te3 nanoplates were achieved with NaOH concentrations of 5–7 M.
► Hexagonal Bi2Te3 nanorings were fabricated with NaOH concentrations of 9–11 M.
► Bi2Te3 nanorings were fabricated by dissolving the inner part of the nanoplates with NaOH.