Development of stacked porous tantalum oxide layers by anodization

•Thin porous nanolayers were successfully achieved by an electrochemical process.•Ta2O5 nanolayers obtained by anodization using HF-free electrolyte.•Electrolyte concentration and the applied potential greatly affect anodic oxide morphology.•F-doped Ta2O5 anodic layer revealed an amorphous structure.•These staked porous layers are suitable for photocatalysts and electronic industry.