Solar photocatalysts based on titanium dioxide nanotubes for hydrogen evolution from aqueous solutions of ethanol

Titanium foil was anodized to grow titanium dioxide nanotubes (TiO ₂ NT) by using an original technique. A solution of ethylene glycol and ammonium fluoride with a concentration of 0.5 wt% was employed as electrolyte, corrosion-resistant steel was chosen as the cathode material. Anodic oxidation was carried out potentiostatically at a voltage of 60 V at ambient temperature for 90 min. Modification of as prepared TiO ₂ NT were modified by calcination in air at 350°C for 4 h. Platinization of TiO ₂ NT was carried out by chemical reduction of platinum from H ₂PtCl ₆ solution by NaBH ₄ solution. Photocatalyst characterization was performed by using XRD, BET, SEM, XPS techniques. It was found that the calcination of as-prepared TiO ₂ NT leads to 6-fold increase of the photocatalytic activity under UV-irradiation. The enhanced activity of TiO ₂ NT is associated with the developed specific surface area and unique morphology of TiO ₂ NT. This results in high rate of separation of photogenerated excited electrons and holes. Due to high separation rate the catalytic activity increases substantially.