Preparation and crystalline phase of a TiO2 porous film by anodic oxidation

Anatase titanium dioxide is an active photocatalyst, but it is difficult to immobilize on the substrate. A crystalline TiO2 porous film was prepared directly on the surface of pure titanium by anodic oxidation in this work. Constant voltage and constant current anodic oxidation were adopted with sulphuric acid used as the electrolyte, pure titanium as the anode and copper as the cathode. The morphology and structure of the porous film on the substrate were analyzed with the aid of Field Emission Scanning Electron Microscopy (FESEM) and X-ray Diffraction (XRD). The effects of the parameters of anodic oxidation (such as voltage, the concentration of sulphuric acid, anodization time and current density) on the aperture and the crystalline phase of the TiO2 porous film were systematically investigated. The results indicate that the increase of current density facilitates the augment of the aperture and the generation of anatase and rutile. In addition, the forming mechanism of anatase and rutile TiO2 porous films was discussed.