Formation of Anodic Oxide Nanotubes in H2O2 - Fluoride Ethylene Glycol Electrolyte as Template for Electrodeposition of α-Fe2O3

Anodic oxidation of titanium (Ti), zirconium (Zr) and niobium (Nb) foils in fluoride ethylene glycol (EG) added to it 1 ml H2O2 as oxidant was done to produce oxide film with ordered porous or nanotubular structure at 40 V. Whilst arrays of aligned, self-ordered nanotubes were successfully formed on the surface of Ti and Zr, anodic Nb2O5 was found to consist of less ordered, nanoporous structure. In this electrolyte, long nanotubes were formed on both Ti (2 mu m) and Zr (3 mu m) after 30 min of anodic process but the surface of the nanotubes suffered from dissolution at certain parts of the sample. The surface quality is important as the oxide surface is to be used as a template for subsequent deposition of nanoparticles. Anodisation of Ti in excess H2O2 (5 ml) fluoride EG was found beneficial in ensuring homogenous surface dissolution forming flat surface oxide suitable as template. Onto this TiO2 template, alpha-Fe2O3 were electrodeposited at -3 V from chloride solution.