Fabrication of high specific surface area TiO2 nanopowders by anodization of porous titanium

The specific surface area of TiO2 powders is an important factor affecting the performance. In this study, we present a simple and novel method to fabricate TiO2 nanopowders based on electrochemical anodization. TiO2 nanopowders with coral-like structure surface and maximum specific surface area of 280 m2/g were fabricated in an aqueous electrolyte containing 1 M Na2SO4 and 0.5 wt% NaF under applied potential of 10 V. Porous titanium as an anodic substrate enhances the reaction rate and promotes the shedding of nanotube fragments. The reaction yield of powders prepared at high-frequency 10 V is nearly 3.7 times higher than that prepared at constant potential 10 V. The specific surface area of the powder prepared at high-frequency-15 V is 61% higher than that prepared at constant potential 15 V.