Effect of the surface configuration on the oxidation of bismuth nanowire

Incorporating nanoprocessing into the metal oxidation, it was a facile way to synthesize functional oxide with desired nanostructure. In this work, δ-Bi2O3 nanowires were successfully fabricated by the oxidation of electroplated Bi nanowires at 350 °C. δ-Bi2O3 is the high-temperature phase of Bi2O3 and only stable at 723–823 °C. Partially oxidized nanowires showed core-shell structure composed of metallic Bi and δ-Bi2O3. To investigate the mechanism of oxidation reaction, the Bi/Bi2O3 interface was characterized by high resolution transmission electron microscopy (HRTEM). HRTEM images showed rapid growth of oxide layer on (21¯0) plane of rhombohedral Bi metal. The coherency between (102¯) of metallic Bi and (1 0 0) of cubic Bi2O3 was observed. A schematic model was also used to describe the oxidation process. The coherency Bi and Bi2O3 and the stabilization of high-temperature (fluorite structure) Bi2O3 were also discussed based on this model.