Effect of applied voltage and fluoride ion content on the formation of zirconia nanotube arrays by anodic oxidation of zirconium

Anodised zirconium (Zr) foil at 20 V for 1 h in Na2SO4 with 0.5 wt.% NH4F resulted in 6 μm thick anodic oxide film with nanotubular structure. At 50 V the anodic layer is consisted of an irregular inner layer with the nanotubular structure only at the top of the layer. Nonetheless, the anodic oxides formed are crystalline and photocatalytic ability of the anodic oxide was assessed by photodegradation of methyl orange.

Research highlights
► We study formation of anodic zirconia on zirconium foil by anodisation in 1 M Na2SO4 with NH4F at 20 V and 50 V.
► The presence of fluorine ions has induced crystalline anodic oxide with nanotubular structure.
► The nanotubular arrays were self-organized and had proven to have good photocatalytic property.
► We stated the reason for the formation of crystalline nanotubular anodic oxide is stated.