Fabrication of Ta2O5 nanostructure films via electrochemical anodisation of tantalum

Abstract

In this work, we report the electrochemical formation of Ta2O5 films with different morphology via one-step anodisation of tantalum foil in aqueous electrolytes consisting of H2SO4 and fluoride ion and small additions of ethylene glycol or glycerol. The morphology and structure were characterised by field emission scanning electron microscopy (SEM), X-ray diffraction and energy dispersive X-ray spectroscopy. SEM results show that under optimised electrochemical conditions in electrolytes containing H2SO4 and fluoride ion, Ta2O5 nanotube layers can be grown up to thickness of 2 μm. The addition of ethylene glycol or glycerol to this aqueous electrolyte resulted in the formation of irregular porous or compact films on the surface of tantalum. The photocatalytic activity of films was evaluated by measuring the degradation of methylene blue under UV irradiation. Ta2O5 nanotubes exhibited higher photocatalytic activity than did the other samples. The reason of this enhanced photocatalytic property can be attributed to high specific surface areas and the nanotube structures of this sample.