In situ XPS study of template-free electrodeposition of antimony nanowires from an ionic liquid.

Antimony nanowires have been synthesized by template-free electrodeposition at room temperature from the ionic liquid (IL) 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ([Py1,4]TFSI) containing 0.5 mol/L SbCl3. The nanowires are shown to have a diameter of ~ 50 nm and a length of ~ 10 µm. Sb nanowires can only be obtained by a two-step electrochemical process, requiring first a cyclic voltammetry step followed by the electrodeposition step. In situ XPS is employed to investigate the speciation formed during the electrochemical reduction process. The results reveal that the XPS core level peaks of the IL and of SbCl3 components shift their binding energies towards higher values accordingly with the applied negative cell voltage. Additional peaks at lower binding energies than those of Sb3+/IL at the OCP can be attributed to the adsorption of reduced Sb species. The formed species together with the IL solvation layers play an important role in the formation of Sb nanowires. [ABSTRACT FROM AUTHOR]