Understanding of anodization of zinc in an electrolyte containing fluoride ions

Anodization of a Zn foil was investigated in aqueous acidic and neutral electrolytes. It was found that nanowire-like structures can be prepared when it is anodized in an electrolyte containing F− ions under appropriate conditions. In particular, abundant F− ions were detected in the samples with a spiked morphology, which was revealed as ZnF2. Different pathways for the formation and dissolution of ZnO were suggested to explain the mechanism for the formation of ZnF2 nanowires. Dissolution of ZnO at a low potential is mainly attributed to chemical dissolution by H+ or OH−, whereas electrochemical dissolution by anions in the electrolytes accounts for the formation of nanowires at a high potential. XRD data and XPS measurements confirm that the anodically prepared nanowire-like structure consists of ZnF2.