Optimization of Routes for the Synthesis of Bismuth Nanotubes: Implications for Nanostructure Form and Selectivity

In this paper, we demonstrate a new route for synthesis of bismuth nanotubes (BiNTs) based on chemical reduction using sodium borohydride. A comparison and an optimization of different synthesis procedures including hydrothermal and solvothermal synthesis for the production of BiNTs are presented. The effects of parameters such as the bismuth precursor, temperature, and reagent mixing process on nanomaterial structure were evaluated. X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), and Raman spectroscopy were employed to characterize the products from the different reaction schemes. A postsynthesis sodium borohydride treatment improved both yield and nanotube structure for all syntheses studied. Different morphologies of the bismuth nanostructures were observed depending on the synthesis method selected.